T he J ournalofthe A erospace M edicine
Transcription
T he J ournalofthe A erospace M edicine
T h e J o u r n a l o f t h e A u s t r a l a s i a n S o c i e t y o f A e r o s p a c e M e d i c i n e Vo l ume 6 Num ber 1 Decem ber 2011 2 | JASAM Vol 6 No 1, December 2011 Editorial. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Original Articles What’s wrong with the Age 65 Rule? – The evolution of the Age 60 Rule Jeff Stephenson OAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Colour perception standards in aviation: Some implications of the AAT decisions regarding colour perception and aviation Arthur Pape et al . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Knowledge from the Aviation Industry Adapted for the Management of Victorian Trauma Patients Melinda Truesdale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 The Advantages of a DAME Database Dave Baldwin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Implantable Cardiac Devices in the Military Aviation Environment Paul Kay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Reprint Frequent users of the Royal Flying Doctor Service primary clinic and aeromedical services in remote New South Wales: a quality study David L Garne et al . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2010 DINNER PRESENTATION How to earn a Golden Caterpillar AVM Eric Stephenson AO OBE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2012 International Congress of Aviation and Space Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2010 Annual Scientific Meeting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2011 Annual Scientific Meeting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Honorary Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 ASAM Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 2011 Membership List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Information for Authors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 JASAM (ISSN 1449 – 3764) is the official journal of the Australasian Society of Aerospace Medicine. © Copyright ASAM 2006 Website: www.asam.org.au Address: PO Box 4022, BALWYN, VIC, 3103, AUSTRALIA JASAM Vol 6 No 1, December 2011 | 3 EDITORIAL The value of annual scientific meetings Annual scientific meetings (ASM) have been a long standing and integral feature of the Society’s history over the past six decades. As well as providing a forum for the essential legal requirements for annual general meetings which are necessary for all incorporated organisations, the ASM have provided vital opportunities for formal and informal discussion and exchange of information on aerospace skills, knowledge and experience. Our society has a fortunate culture of warmth, support and camaraderie and this results in a large percentage of members who regularly attend the ASM. Over the past decade, there has been an increasing demand for evidence based medicine, as well as increasingly requirements for, and now mandated, continuing professional development, in a now highly evolved information technology environment where computer literacy has now become an essential skill for professionals. Our Society has adapted to these changes and this is particularly noticeable at the ASM with the increase in the quality of the presentations. Active involvement in presentations has been enhanced by the use of wireless remote responders to select answers posed by presenters, and the Society is greatly appreciative to CASA for the provision of this technology. The introduction of a theme for the ASM over a decade ago has resulted in selection speakers to complement the expertise of the John Lane Trust and Patterson Trust orators. This has provided a benefit of both broadening the content and depth of current knowledge in clinical areas resulting in review and revision of the aerospace implications for the wider aerospace community, and mirrors the process adopted by CASA over recent years in updating the DAME Handbook. Selection of a topic for the ASM has focused the energy of organising committees as well as revealing their creative ingenuity in developing appropriate themes to encapsulate the topic: the 2005 ASM on fatigue management was held on the Gold Coast with the theme ‘Asleep in the sun’; mental health was the topic in Launceston in 2006 ‘ A flight of ideas’; Avian influenza and infectious disease was the topic in Busselton in 2007 ‘There is something in the air’; the 2008 ASM held in Darwin on commercial space flight had the theme ‘Frontiers of aerospace medicine’; while cardiac arrhythmias were discussed in Canberra in 2010 with the appropriate theme “The heart of the nation’. The most difficult challenge was selection of a theme for the 2011 ASM to cover the topics of ophthalmology and endocrinology. Dr Gordon Cable is acknowledged for his inspirational idea for the theme ‘Keeping your eye on the ball’! One of the consequences of these changes is that feedback following the ASMs has been very positive and frequently accompanied by the comments ‘Best one ever’. This is rewarding to the organisers as well as the committee as it means that the ASMs are meeting the needs of our members who pursue excellence and currency in aerospace medicine. With the emphasis of evidence based medicine, there may be a tendency to dismiss and devalue the opinions and experiences of individual practitioners, often disparagingly called ‘eminence based medicine’. Those who only value observational data are advised to read the article challenging evidence based medicine detailing where a systematic literature review failed to reveal any published evidence that parachutes work1. But there remains an important role for individual experience and opinion. It is through experience that orthodoxy may be challenged or hypotheses can be developed. There is a richness and diversity of individual experience in aerospace medicine and this should continue to be encouraged at ASMs. 4 | JASAM Vol 6 No 1, December 2011 In this edition of the journal, four articles are published from presentations at our ASMs that relate to this concept. Our reviewers were divided on the controversial article on colour vision in aviation by Arthur Pape, known for his successful challenge on aviation colour vision policy to the Administrative Appeals Tribunal2 over two decades ago. In his article, Pape again challenges the reader and proposes that the presence of colour is neither sufficient nor necessary for appropriate information processing. He argues his case well and provides supportive examples. However, readers are invited to challenge the rejection of the third assumption detailed in the article. A clue is in the ICAO colour perception standard: “The applicant shall be required to demonstrate the ability to perceive readily those colours the perception of which is necessary for the safe performance of duties.” Melinda Truesdale’s article on “Knowledge from the Aviation Industry Adapted for the Management of Victorian Trauma Patients” discusses how the highly successful crew resource management (CRM) developed in the aviation industry to combat a number of accidents in which poor teamwork in the cockpit had been identified as a significant contributing factor, can be successfully migrated to the hospital emergency department. She provides an overview of training of hospital staff in what she terms ‘Crisis Resource Management’. In another different paradigm of the practice of aerospace medicine, Dave Baldwin discusses the use of a database he uses for the conduct of aviation medical examinations as he travels to aircrew as a flying aviation medical examiner, as an alternative to aircrew attending his clinic. Finally, our esteemed and highly respected honorary member, AVM (Ret) Dr Eric Stephenson AO OBE publishes the after dinner talk he presented at the 2010 ASM at the Australian War Memorial under the Lancaster bomber ‘G for George’ on how he gained his ‘Golden Caterpillar’. This was an inspiring personal experience of his combat experience from World War 2 and was appropriately rewarded by a standing ovation. May our members continue to share their aerospace experiences at future ASMs. Warren Harrex References 1.Smith GCS, Pell JP. Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. BMJ. 2003 December 20; 327(7429): 1459–1461. 2.Administrative Appeals Tribunal: Re: ARTHUR MARINUS PAPE and SECRETARY, DEPARTMENT OF AVIATION. No. V87/494 AAT No. 3821 Air Navigation ORIGINAL ARTICLE What’s wrong with the Age 65 Rule? – The evolution of the Age 60 Rule Jeff Stephenson OAM MBBS MAvMed DipAeroRet Abstract For nearly 50 years in the USA, the Age 60 Rule mandated the compulsory retirement of commercial aviation pilots upon reaching the age of 60 years. This age-based retirement rule was recently amended to age 65 years. The reasons behind these rules are discussed. A discussion of ageing and its effect on the pilot is included. Alternatives to an age-based system are provided with reference to the literature on ageing and pilot performance. Acknowledging the role that older pilots have in the aviation environment, some guidelines are suggested to accommodate their needs and to make the aviation environment safer. Introduction The Age 60 Rule was implemented by the Federal Aviation Administration (FAA) in 1959. Simply stated it did not permit U.S. based pilots or co-pilots engaged in commercial passenger transport (Part 121 of the FAA regulations), to continue flying after their 60th birthday1. This controversial rule was implemented by the FAA in 1959 and its validity had been hotly debated and challenged ever since. On 13 December 2007, after nearly half a century, the Age 60 Rule was altered with the signing of a Bill called the “Fair Treatment for Experienced Pilots Act”. When President Bush signed this Bill he effectively changed the Age 60 Rule to the Age 65 Rule. The reasons for the implementation of the age 60 rule – controversies and debate The reasons provided for the implementation of the Age 60 Rule range from the pseudo-scientific, albeit with scant objective evidence, through to the conspiratorial. Amongst the reasons provided were the difficulties that older pilots were encountering in transitioning to new turbo-jet aircraft and the involvement of a 59 year old pilot in a crash of a new-model aircraft. In addition, there was an increase in the number and percentage of older pilots and also an increased prevalence of heart disease amongst older individuals. The principle concerns articulated were related to the risk of sudden pilot incapacitation, degraded performance and subtle performance decrements due to ageing2. Amongst other theories explaining the origin of the Age 60 Rule are those claiming that the rule was instituted to allow airlines to retire more expensive senior captains and promote the less expensive first officers. In addition, the airlines were able to age-retire their pilots at age 60 years, which was in keeping with the 1950’s approach to employee management. Obviously, for some junior pilots this was seen as a good thing – permitting them to get into the “left seat” earlier. The main protagonists around this time were the founder and CEO of American Airlines, C.R. Smith and Gen. E. R. Quesada the first appointed administrator of the newly created FAA. Amongst the 10,100 web sites found on a Google search of “Age 60 Rule” are many that allude to the conspired “smokey back room deals” and “Age-60 Fraud” that is alleged to have occurred9. Author details Dr Jeff Stephenson OAM MBBS MAvMed DipAeroRet, Senior Medical Advisor, 3EHS, RAAF Richmond, NSW 2755 Correspondence [email protected] Other approaches to implementing an age 60 rule The Joint Aviation Authorities (JAA – a 42 member aviation regulatory body consisting of member countries from the European Civil Aviation Conference (ECAC) also prohibits a pilot who has attained the age of 60 years from engaging in commercial air transport operations. The JAA is slightly more liberal than the FAA and will allow an exception to the rule for a pilot between the ages of 60 to 65 to pilot an aircraft, where he or she is the only pilot crew member who is over 60 years1. The International Civil Aviation Organisation (ICAO – an international organisation with 190 contracted states) also limits the age for a pilot and co-pilot to 60 years. However, many of the member states have notified ICAO of their intention to not comply with the rule – with some countries raising the limit, several lowering the limit and some doing away with it altogether5. Australia, Canada and New Zealand have strong anti-discrimination laws which prohibit discrimination on age grounds and thus these countries do not implement an Age 60 Rule at all. Evolution and studies relating to the implementation of the age 60 rule Principle reasons for implementing an age rule The major considerations for implementing an “Age Rule” relate to an ageing pilot: 1. having subtle and undetected cognitive decline and decreased psychomotor skills; 2.being at increased risk of sudden incapacitation; and, 3.that medical screening may fail to detect which pilots are at risk for adverse events6. Pilot incapacitation When the Age 60 Rule was first implemented, pilot incapacitation was cited as one of the major concerns. Proponents of retaining the Age 60 Rule placed emphasis on pilot incapacitation as a cause of diminished flight safety. However, when compared to human-factors causes, pilot incapacitation has been shown to be an uncommon cause of aircraft accidents7-9. Whilst in-flight discomfort is not an infrequent occurrence, (most commonly due to gastrointestinal disorders), only a small proportion of such in-flight physiological events were deemed to be a threat to flight safety6,10. To gain some perspective on the relative risk of pilot incapacitation, various authors have calculated the accident rate per number of flying hours where pilot incapacitation was considered a causative factor11. One author has derived a figure of approximately one pilot incapacitation associated accident for every 1010 flying hours (1 in 10-10) – which is many orders of magnitude less than the accepted accident rate from airframe failure (1 in 10-5)11. Ageing Whilst it is almost universally accepted that age-related changes will affect a pilot’s skills, it should be emphasised that ageing is a non-linear process. Ageing will occur at different times for different body systems, and proceed at different rates amongst individuals within a population12. The process of ageing is progressive and continuous1. Studies have shown that the ageing process results in a general decrease in working memory (fluid memory) capacity and central processing speed13. There have been multiple studies documenting age-related physiological declines in vision, hearing and perceptual motor skills14-16. Cognitive performance also exhibits a decline with age18, however time-sharing tasks may not be affected18. It is generally believed that aviation expertise (crystallised memory) decreases JASAM Vol 6 No 1, December 2011 | 5 What’s wrong with the Age 65 Rule? the effects of age–related decline in memory tasks19, although the results in some studies do not support this view14. Studies on attention and concentration have shown similar mixed results with some studies showing age-related decline18, and others showing the attention performance of older pilots being equal to that of younger pilots20. by the same authors which showed a clear decline in pilot performance with age, although the authors stressed that age only explained 22% or less of the observed performance variation on different flight tasks28. Another paper from 1989 reported that older pilots exhibited greater deviation from a prescribed flight path when compared to their younger colleagues29. Sleep An area of particular concern when considering the implementation of an age rule is the evidence obtained from sleep studies. These studies have documented that older pilots will experience greater sleep loss in long haul operations, with the increased loss being proportional to increased age15. If an age rule is not implemented for pilots, due consideration should be given to the fact that sleep loss has been implicated as a human factor in accidents and incidents21. Hearing Hearing is another important physiological parameter that has been shown to have an age related decline. The process of presbycusis can be exacerbated by noise induced hearing loss (NIHL) and there is data suggesting that some older pilots may not hear higher frequency alarms in the cockpit22. Vision Figure 1: A portion of the CogScreen-AE showing a symbol digit coding task. With all the CogScreen-AE subtests, a practice session precedes the test itself. The CogScreen-Aeromedical Edition (CogScreen-AE) is a computer-administered and scored cognitive-screening instrument designed to rapidly assess deficits or changes in attention, immediate – and short-term memory, visual perceptual functions, sequencing functions, logical problem solving, calculation skills, reaction time, simultaneous information processing abilities and executive functions. Source: Westerman R, Darby D, Maruff P, Collie A. Computer-assisted cognitive function testing of pilots – ADF Health April 2001 Vol. 2 No. 1. http://www.defence.gov.au/health/infocentre/journals/ADFHJ_apr01/ ADFHealthApr01_2_1_29-36.pdf It is estimated that at least 80 per cent of all information acquired by pilots is derived through the sense of vision. Pilots gather visual information both from their instruments within the cockpit and from looking through the windscreen canopy23. Excellent corrected visual acuity is required for approach and landing, and for spotting other aircraft24. Good corrected near visual acuity is required for reading aircraft instruments and maps. Most neonates are hypermetropic and the magnitude of this increases to a peak at about eight years of age, when the refraction becomes relatively myopic until about 40 years of age23. With middle age there is increasing hypermetropia due to the loss of accommodative power. Finally, after the age of about 75 years the crystalline lens becomes sclerotic, with a higher refractive index and a tendency back towards myopia.23. The progression through this typical pattern is variable and unable to be accurately predicted24. Ageing of the eye leads to sclerosis of the crystalline lens, which leads to gradual loss of accommodative power. This effect usually becomes marked during the fifth decade, resulting in the need to wear corrective spectacles for near vision. In addition to the loss of accommodative power, the ageing eye is slower to accommodate with older pilots requiring up to ten times as long to accommodate when compared to younger pilots16. Whilst some studies show age-related differences in simulator perfomance28,29, others do not10,14,30. There are several limitations to interpreting simulator analysis studies of pilot performance. Firstly, most of the studies have been cross-sectional studies, with the exception of the Yesavage et al. study which was a longitudinal study conducted on 100 pilots over three years28. A further limitation of studies is that there are few subjects aged over 60 years-old with current airline flight time (as they have been retired prior to 13 Dec 2007 due to the Age 60 Rule). This has dictated that most simulator studies are performed on small-aircraft flight simulators – airframes that general aviation (GA) pilots over 60 years retain currency on. Cognitive skills Flight performance Ageing is accompanied by a general decline in cognitive function, although it is rarely manifest before the age of 70 years14. Fortunately, airline pilots have been shown to demonstrate superior task performance when compared to age-matched non-pilots26. However, within the broad area of cognitive functions analysed there was significant variation, with perceptual-motor skills and memory tasks being the most affected14. The evidence supporting the implementation of an Age 60 Rule is not strong when flight performance is analysed independently. Several studies confirm there is a decline in accidents as pilots’ age (and experience) increases31,45. This decline continues to around the age of 65 years when it begins to increase again31; thus demonstrating a “U-shaped” relationship between accident rates and pilot age. The total number of accidents involved in air carrier accidents is small and this gives any study on Age versus Flight Performance (as measured by accident rates) less power. Simulator performance An area that has been used to assess pilot capacity is the flight simulator environment. There have been concerns expressed that simulator results may be invalid as insufficient workload can be generated to test whether an impaired pilot could perform time-sharing tasks at adequate speed1. A study by Taylor et al demonstrated that the CogScreen – Aeromedical Edition (CogScreenAE) – a cognitive battery of tests to assess pilots in simulated flight – was a valid method of investigation27. This study followed on from an earlier paper 6 | JASAM Vol 6 No 1, December 2011 A study by Kay et al. demonstrated a gradual decline in accident rates for pilots with a Class II or III licence until the early 60’s followed by a slight increase from age 65 to 69 years31. Similarly, another study conducted on GA pilots demonstrated that older pilots were at decreased risk for accidents and violations when compared to younger pilots32. Other studies do not support any relationship between pilot age and accident rates33. What’s wrong with the Age 65 Rule? operating in a two pilot environment can be considered for a continuation of flight status by use of the 1% rule. It may be more appropriate to adopt a functional approach for the aging pilot, rather than adopt a broad ruling of compulsory age retirement. The concept of functional age – should it replace implementation of an age rule? Figure 2: The Sioux City Crash – where age and pilot experience proved beneficial Photo: Source unknown. Prior to 2000, Japan permitted pilots up to age 63 years to fly air-carriers. A study of the over 60-years pilots in Japan found a zero accident rate over a three year study interval. As a consequence of this finding, the pilot age limit was raised to 65 years for Japanese pilots34. It has been proposed that “functional age” (the equivalent chronological age that a pilot performs to), rather than biological age should be used to assess the ability of a pilot to continue to fly40,41,42, although some authors do not believe this is a viable alternative14. Sophisticated neuropsychological tests, such as the CogScreen-AE have been validated as demonstrating age-related performance decrements27,43. Further refinement of this type of testing may be a method to ascertain a pilot’s flight safety, however it will be an expensive process to fully validate such a system. The corollary of the adoption of a functional assessment of a pilot’s safety is that some pilots aged less than 60 years will be deemed unsafe to pilot aircraft. How implementing an Age 60 Rule leads to “medical” wastage DeHart, Stephenson and Kramer examined the aircrew selection program for RAAF applicants between 1969 and 197335. The term medical wastage was used to describe that group of unsuccessful applicants who were rejected for medical reasons, and this terminology was previously used by Bennet and O’Connor when they examined civil aircrew in Great Britain36. Historically there is usually a high supply of pilots satisfying demand from the commercial and military recruiting environment. However, there are times when the number of applicants decreases, thus lessening the supply. Several studies and papers describe this fluctuation and comment that a consequence is a need to review, and to sometimes relax standards35,37. An analogous situation occurs at the end of a pilot’s flying career. The enforced age-retirement at age 60 of healthy and experienced pilots is another example of medical wastage and some claim it wastes the skills of thousands of capable pilots38. Aeromedical decision making (ADM) and the implementation of an age rule The principles of ADM The aviation clinician makes aeromedical decisions on a regular basis. The basic principles of ADM involve an acknowledgment that each case is decided on its merits, a consideration of whether the medical condition has implications for flying safety and whether the aviation environment will have an effect on the condition or its treatment39. The implementation of an age rule for retirement ignores the concept of ADM and replaces it with a compulsory retirement rule. ADM for retirement age versus an Age Rule ADM should examine the risk of a sudden incapacitation (such as occurs for example with severe disabling chest pain), the risk and effect of loss of function (for example a visual field defect in a stroke) and whether the condition predisposes to an adverse interaction with the physiological stressors of flight (for example the increased risk of sleep deprivation in an older pilot conducting long haul operations). ADM is essentially risk management. Aerospace medicine has traditionally been conservative and risk averse39, however this must be tempered with the potential loss of experienced trained pilots. If the principles of risk management are utilised a pilot with an identified medical problem, Figure 3: US Airways flight 1549 crash-landed into the Hudson River on 16 Jan 2009. The captain of the aircraft, Chesley B. ”Sully” Sullenberger was aged 57 years and had 40 years flight experience. Lauded by many as an example where the pilot’s experience was able to prevent a catastrophic outcome. All of the 146 passengers and five crewmembers aboard the plane survived the water landing. Photo: Brendan McDermid/Reuters http://www.time.com/time/ photogallery/0,29307,1872172_1826294,00.html Accessed 18 Jan 2010. Alternatives to retaining the Age 60 Rule The Aerospace Medical Association in a Position paper from 2004 proposed several alternatives to the Age 60 Rule1. These included: 1.Abandoning the Age 60 Rule and relying on six-monthly medical and performance (simulator and actual flight) testing; 2.Replacing the Age 60 Rule with other unspecified tests; or 3.Increasing the Age 60 Rule to Age 65, and examining the results of such a change in longitudinal studies. On 13th December 2007 the Age 60 Rule was replaced by option three, and a Bill was signed effectively changing the Age 60 Rule to the Age 65 Rule43. The concept of “age-proofing” for older pilots With the implementation of an Age 65 Rule there would appear to be a number of relevant safety issues that should be addressed or recognised. By recognising the limitations that older pilots have, airline regulators may further promote safety in older pilots by adopting strategies such as those I propose JASAM Vol 6 No 1, December 2011 | 7 What’s wrong with the Age 65 Rule? below. I have termed this concept “age proofing” the cockpit. Disclaimer 1.It has been documented that cockpit alarms at higher frequencies may be inaudible to older pilots22. Aircraft design engineers should ensure that audible alarms are of lower frequencies. The views, opinions, and/or findings in this report are those of the author and should not be construed as an official policy of the Royal Australian Air Force or the Australian Defence Force. 2.Older pilots will inevitably be required to convert onto newer airliners from time to time. The failure rate for conversion to new aircraft increases with increasing age45. This fact should be borne in mind by flight trainers and by examining instructors. The implementation of an Age 65 Rule will lead to an older pilot cohort. Subsequently consideration should be given to additional training time for older pilots on conversion courses. References 1. Aerospace Medical Association, Aviation Safety Committee, Civil Aviation Safety Subcommittee. The age 60 rule. Aviat Space Environ Med 2004; 75:708-715. http:// docserver.ingentaconnect.com/deliver/connect/asma/00956562/v75n8/s12.html?ex pires=1204935536&id=42814302&titleid=8218&accname=Guest+User&checksu m=AF84F34DDAC45F352DE7A6F83A8139E2 Accessed 2 Mar 2008. 3.The modern “glass cockpit” has increasing amounts of automation contained within it. Pilots are known to experience problems with automation, and it has been implicated as a factor in aviation accidents20. Automation is also a key component of Crew Resource Management (CRM) training20. The older pilot will have less experience with electronic automation and additional training with this technology should be given to the older pilot. 2.Airline Pilots Association (ALPA) (1959b). Special report: APLA supplementary brief submitted to FAA on pilot age limitation question. The Airline Pilot, 28: December 1959, 16-20. 4.Currency of flying time is associated with a lower risk of pilot accident46. Older pilots should be discouraged from taking lengthy breaks from flying duty (such as long service leave) between the ages of 60 to 65 years. It would be more appropriate to take this leave earlier than 60 years or immediately pre-retirement. 5.Curdt-Christiansen CM. The case for an international upper age limit for airline pilots. Aviat Space Environ Med 2002; 73:309. 5. Consideration should be given to giving older pilots additional medical and neuropsychiatric testing at more frequent intervals. Certainly, in some countries, the frequency of medical examination for certain areas such as vision and the resting ECG increases in frequency with the increase in pilot age47. Neuropsychiatric testing however is not routinely done and would need to be developed and validated. The cost of these additional and more frequent medical examinations would be significantly less than the cost of training a new pilot. However, a problem arises as the US “Fair Treatment for Experienced Pilots Act”, made law in December 2007, states that a pilot shall not be subject to different medical standards, or more frequent medical examinations on account of age43. This would appear to be a flaw in the US regulations as it does not allow for a more flexible approach to medical or neuropsychiatric testing. The future of age rule implementation The recent change from an Age 60 Rule to an Age 65 Rule will effectively cease the Age 60 debate that has existed for the last 49 years. Within the next five years, though, the Age 65 Rule will be analysed, criticised and legally challenged. At this stage the use of a functional assessment has not been fully investigated or trialled. If a functional assessment was proven to be a valid method of assessing an aging pilot, then the Age Rule may be discarded. This is unlikely to occur in the foreseeable future. Conclusion Many countries have already discarded the Age 60 Rule. Recent legislative changes in the USA have led to the passing of the era of the controversial Age 60 Rule in that country. Intensive investigation by multiple authors, over many years, has failed to reach consensus on the most appropriate age for a pilot to be retired form flight duty (if indeed one exists). There is evidence confirming the association between increasing pilot age and a decline in psychomotor function. On balance, the expertise and experience that a pilot has gained during an aviation career would not appear to fully offset this age-related decline. The majority of the evidence does suggest that most pilots will function satisfactorily until the age of 65 years. The key debate for the future will be whether to keep the Age 65 Rule and continue age-enforced retirement or to adopt a functional approach. 8 | JASAM Vol 6 No 1, December 2011 3.“Age 60 Rule” Google search. http://www.google.com.au/search?hl=en&q=%22A ge+60+Rule%22&meta= Accessed 8 Mar 2008. 4.Joint Aviation Authorities, The European Joint Aviation Authorities Membership http://www.jaa.nl/introduction/introduction.html Accessed 8 Mar 2008. 6.Wilkening R. The age 60 rule: age discrimination in commercial aviation. Aviat Space Environ Med 2002 Mar;73(3):194-202. http://chemport.cas.org/cgi-bin/ sdcgi?APP=ftslink&action=reflink&origin=catchword&version=1.0&coi=1:STN:28 0:DC%2BD387ns1WitQ%3D%3D&md5=21e284188fb6e43302c6332fce43d9ac Accessed 12 Mar 2008. 7.Simmons M, Valk PJL, Krol JR, et al. Consequences of raising the maximum age limit for airline pilots. Proceedings of the Third ICAO Global Flight Safety and Human Factors Symposium; 1996; Auckland. Human Factors Digest No. 13; CIRC 266AN/158:248-55. 8.Larcher JG, Veronneau SJH, DeJohn CA. In-flight medical incapacitation research. Aviat Space Environ Med 2001; 72:306. 9.Froom P, Benbassat J, Gross M, et al. Air accidents, pilot experience, and diseaserelated in-flight sudden incapacitation. Aviat Space Environ Med 1988; 59:27881. http://www.ncbi.nlm.nih.gov/pubmed/3355485?dopt=Abstract Accessed 8 Mar 2008. 10.James, M., & Green, R. Airline pilot incapacitation survey. Aviat Space Environ Med, 62, 1068-1072. http://chemport.cas.org/cgi-bin/sdcgi?APP=ftslink&action=reflink &origin=catchword&version=1.0&coi=1:STN:280:By2D2svptl0%3D&md5=150fb 2f88b176acc6d1a24544dde9eb1 Accessed 12 Mar 2008. 11.Chapman, P. The consequences of in-flight incapacitation in civil aviation. Aviat Space Environ Med, 55, 497-500. http://chemport.cas.org/cgi-bin/sdcgi?APP=ft slink&action=reflink&origin=catchword&version=1.0&coi=1:STN:280:BiuB2sbovV A%3D&md5=f1b9bea88b965937c53d03829a2b4510 Accessed 12 Mar 2008. 12.Griffiths R. University of Otago, Masters in Aviation Medicine 2008. AVMX711 Aviation Physiology Module One Tutorial 4 Mar 2008; Aging and Performance. 13.Salthouse TA. Influence of experience on age differences in cognitive functioning. 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Int J Aviat Psychol 1991; 1:23143. http://lysander.ingentaconnect.com/vl=2518408/cl=15/nw=1/rpsv/cgi-bin/ linker?ini=dragonhat&ref=asma_asem_1755_b43-1755___v75n8 Accessed 11 Mar 2008. JASAM Vol 6 No 1, December 2011 | 9 ORIGINAL ARTICLE Colour perception standards in aviation: Some implications of the AAT decisions regarding colour perception and aviation Arthur Pape, MBBS (Melb), Boris Crassini, BA (Hons), PhD Abstract The International Civil Aviation Organisation (ICAO) colour perception standard may be analysed as a form of argument; that is, it may be considered as a conclusion drawn logically from three assumptions. These assumptions are (i) that colour is used extensively as a feature of information-presentation systems in aviation; (ii) that normal colour vision is necessary for safe information processing from such systems, and consequently, safe performance of the duties of aviation, and (iii) that defective colour vision results in unsafe information processing from such displays, and consequently, unsafe performance of duties in aviation. For the application of the ICAO colour perception standard to be evidenced-based, the truth or falsity of each of these assumptions needs to be evaluated using appropriate empirical tests. An informal demonstration of an empirical test of the second assumption is presented showing that the presence of colour is neither sufficient nor necessary for appropriate information processing from one informationpresentation system. The limitations of the kind of evidence provided by the demonstration are noted, and a proposal for the collection of more appropriate empirical evidence is proposed. This proposal is possible because of two landmark decisions made some 20 years ago by the Administrative Appeals Tribunal (AAT) in Melbourne, Australia, in relation to the aviation colour perception standard. Because of these decisions, pilots with defective colour perception were able to gain extensive flying experience commanding modern, sophisticated aircraft. That is, a group of pilots with defective colour perception now exists having similar flying experience to the flying experience of pilots with normal colour perception. These two groups of pilots provide a pool of possible participants for a more-appropriate empirical test of the assumption underlying the colour perception standard than had been possible before the AAT decisions. A proposal for such an empirical test is outlined. What is assumed in proposing an aviation colour perception standard? Assumption 1: There is extensive use of colour-coded information in the aviation environment. Assumption 2: The ”safe performance of duties” in the aviation environment requires ”the ability to perceive readily those colours the perception of which is necessary for the safe performance of duties.” Assumption 3: Without ”the ability to perceive readily those colours the perception of which is necessary for the safe performance of duties”, these duties will be performed unsafely. The value of undertaking such a formal logical analysis of the ICAO colour perception standard is that the analysis makes the assumptions underpinning the colour standard explicit, and thereby allows the truth or falsity of the assumptions to be tested. Such tests of the truth or falsity of the assumptions are needed to determine whether the argument based on these assumptions, in this case, the colour perception standard, is true or false. That is, such evaluations of the three assumptions provide an appropriate evidence basis for the colour perception standard. Let us consider in turn each of the three assumptions identified above. There can be little doubt that there is extensive use of colour in systems used to present information in the aviation environment. This use of colour occurs inside modern aircraft where, for example, there is extensive use of coloured displays to present information to pilots. The use of colour also occurs in the aviation environment external to the aircraft, where, for example, there is extensive use of colour in runway and taxiway lighting at airports, and in devices such as PAPI used to help pilots maintain correct glide slope while on approach to landing. Figure 1 shows examples of this use of colour both inside the cockpit of a modern aircraft, and in the environment external to aircraft. More formal support for the truth of this assumption is provided by recent analyses of the aviation environment by Barbur, Rodriquez-Carmona, Evans, and Milburn (2009a, b)2 in which they attempted to provide a classification of the role played by colour in this environment. The International Civil Aviation Organisation (ICAO) colour perception standard for those wishing to apply for a pilot’s licence is set out in the July 2001 Annex 1 to the Convention on International Civil Aviation1, and reads in part: “The applicant shall be required to demonstrate the ability to perceive readily those colours the perception of which is necessary for the safe performance of duties.” The ICAO colour perception standard can be analysed formally as a form of logical argument. In common language, the word ’argument’ refers to a situation where there is some opposition or contradiction in two or more points of view. However, in more formal logical analysis, the word ’argument’ refers to a situation where a conclusion is drawn from one or more assumptions or premises. Analysed formally as an argument, the ICAO colour standard is based on three assumptions, as follows: Author details Dr Arthur Pape, MBBS (Melb) Dr Boris Crassini, BA (Hons) University of Queensland; PhD University of Queensland; Honorary Professor of Psychology, Deakin University. Correspondence [email protected] 10 | JASAM Vol 6 No 1, December 2011 Figure 1. The left panel shows the Pilot Flying Display (PFD) of the Airbus A330. (With permission, QANTAS Training Material) The right panel shows a typical runway lighting system with approach lighting. (www.intertecnica.de) While there is little doubt about the truth of the first of the three assumptions identified above, the same cannot be said about the second and third assumptions. The second assumption underpinning the colour perception standard is that the ”safe performance of duties” in the aviation environment requires ”the ability to perceive readily those colours the perception of which is necessary for the safe performance of duties.” The use of the word ”necessary” makes a strong claim about the role of colour in processing information in the aviation environment. This strong claim is that the use of Colour perception standards in aviation colours in information displays, and the ability of pilots to ”perceive readily” (to quote the ICAO statement) these colours, is a prerequisite or requirement for appropriate information processing, and therefore safe ”performance of duties”. The second assumption, and its strong claim, is problematic. The truth or falsity of this second assumption is an empirical matter, and the kind of empirical evidence used to support the truth of the second assumption has been questioned in the course of the Administrative Appeals Tribunal (AAT) considerations of the colour perception standard in aviation. The basis of this questioning is discussed in more detail below. The third assumption underpinning the ICAO colour perception standard is that without ”the ability to perceive readily those colours the perception of which is necessary for the safe performance of duties”, these duties will be performed unsafely. Implicit in this third assumption is the ’fact’ that there are individuals who do not ”perceive [colours] readily”. It is more than 200 years since the publication of the first scientific paper on defective colour vision by the English chemist John Dalton (see Dalton, 1798)3, in which he described his own misperceptions of colour. Since then, scientific knowledge of human colour perception, both normal and defective, has increased greatly. The procedures available to measure colour perception have also improved, becoming more sophisticated, and enabling more detailed specification of the nature of defective colour perception. In summary, there is little if any doubt defective colour perception is a condition that is readily demonstrated and measured, and is well understood. However, the fact of the occurrence of defective colour perception has no implication about the truth or falsity of the assumption that those with defective colour perception will perform duties in the aviation environment in an unsafe manner. As was the case with the second assumption, the truth or falsity of the third assumption is an empirical question. Furthermore, as was the case with the second assumption, the kind of empirical evidence used to support the truth of the third assumption has been questioned. Before outlining the problems identified during AAT consideration of the colour perception standard in aviation, some discussion of the role of colour in information-presentation systems is warranted. Is colour sufficient or necessary for appropriate information processing of displays in the aviation environment? The mere use of colour in the aviation environment exemplified in Figure 1 has no implications for the truth or falsity of the second and third assumptions identified above. For example, if this use of colour is only for aesthetic reasons, then the question of the role of colour as an information code does not arise; colour is for ’looks’, not for ’information’. However, if colour is present to serve a functional role, not merely an aesthetic role, this raises the question of the nature of the functional role of colour as an information code. Typically in cockpit displays of the type shown in Figure 1, colour is one of several visual information codes (e.g., a verbal code, a spatial code, an achromatic luminance/brightness code) used simultaneously. In such displays, the question of the role of colour as an information code, which is at the heart of the second and third assumptions, becomes a more-complex question. Despite this complexity, the empirical test that is proposed later in the paper will allow appropriate evaluation of the interactions between colour and the other visual information codes present in multi-coded information displays. Before discussing the proposed empirical test of the second and third assumptions, we present an informal demonstration involving the Electronic Central Aircraft Management (ECAM) display in an Airbus A330 aircraft shown in Figure 2. As its name suggests, the ECAM display is designed to provide Airbus A330 pilots with information ”necessary for the safe performance of their duties” in relation to emergencies that may arise in a flight. During an emergency, the display presents automatically, on a need-to-know basis, information about the emergency, the diagnosis of the problem, and the actions that crew need to undertake to deal with the problem. As is clear from Figure 2, colour is used extensively in the ECAM display, and is used, in part, as follows: White colour : Used to show titles on the ECAM display. Green colour: Used to show normal conditions. Amber colour:Used to show abnormal conditions requiring some attention, but no immediate action. Red colour:Used to show abnormal conditions of a serious nature and requiring immediate action. Blue colour: Used to show actions to be undertaken by aircraft crew. Figure 2. The ECAM display from an Airbus A330 aircraft showing the extensive use of colour in the display. (With permission, QANTAS Training Material) The question of interest is whether the colours used in the presentation of these different types of information in the ECAM display are required for the information to be processed correctly. There are two ways of considering this question of interest. The first is to ask whether colour alone is sufficient for the information presented in a coloured display to be processed correctly. Put simply, is it the case that seeing the colour is enough to see the information? The second way of considering this question of interest is to ask whether colour is necessary for the information presented in a coloured display to be processed. Put simply, is it the case that not seeing the colour means that the information is not seen? Figure 3. A version of the lower section of the ECAM display from an Airbus A330 aircraft with the colour retained, but text replaced by # marks. (Devised by Author 2) Figure 3 shows a version of the lower section of the ECAM display shown in Figure 2 in which the colours used in the original display have been retained, but the text has been replaced by # marks. Inspection of Figure 3 shows that the presence of colour alone is not sufficient for meaningful information to be processed. Without the text, the series of coloured hash marks is meaningless. Figure 4 shows a different version of the lower section of the ECAM display JASAM Vol 6 No 1, December 2011 | 11 Colour perception standards in aviation shown in Figure 2 in which the colours used in the original display have been removed, but the text has been retained. Inspection of Figure 4 shows that the presence of colour is not necessary for meaningful information to be processed. The colourless display in Figure 4 clearly shows that the emergency is a fire in engine number 1, and shows also the actions to be undertaken by the crew. hearings, can now, in theory at least, be gathered. The two cases were: Re: ARTHUR MARINUS PAPE And: SECRETARY, DEPARTMENT OF AVIATION (DOA)4 and, Re: HUGH JONATHAN DENISON And: CIVIL AVIATION AUTHORITY (CAA)5. Before commenting specifically on each of the cases, it is instructive to make two general comments about the AAT appeals overall: The first comment is to do with the scope and thoroughness of the AAT process. The two cases, taken together, took up more than 38 days of hearings. Some 25 witnesses were called to give evidence, including airline pilots, air traffic controllers, and expert witnesses from the fields of aviation medicine, optometry, and psychology. In summary, the AAT hearings represented a wide-ranging and thorough consideration of the evidence of relevance to the question of whether there should be a colour perception standard in aviation. Figure 4. A version of the lower section of the ECAM display from an Airbus A330 aircraft with the text retained, but the colours removed. (Devised by Author 2) Taken together, Figures 3 and 4 are compelling demonstrations that colour is neither sufficient nor necessary for meaningful information to be processed from the Airbus A330 ECAM display. Despite the compelling nature of this informal demonstration, we stress that the ’evidence’ it provides is not an appropriate basis for the evaluation of the second assumption underpinning the colour perception standard. Before discussing more appropriate evidence, we want to point out that the Airbus is equipped with an array of devices designed to draw the crew’s attention to the ECAM display. For example, during a condition requiring attention but no immediate action (i.e., a caution condition), a loud single auditory signal is presented, as is a visual display, separated from the ECAM, consisting of the words ’MASTER CAUTION’ in black text on an amber background light. During a serious condition requiring some immediate action, a loud continuous auditory signal is presented, as is a different visual display, separated from the ECAM, consisting of the words ’MASTER WARNING’ in black text on a red background. In summary, in an actual situation of serious equipment malfunction or of imminent danger (e.g., impending stall or dangerous proximity to terrain) information is presented to the crew using multiple sensory modalities, and from spatially-separated sources. What are the implications of multiple sources of information of the type described in the previous paragraph? Whether individuals in the aviation environment are presented with a single source of information, or with multiple sources of information, the question of whether they make proper use of such information so that they engage in ”safe performance of duties” is an empirical question; that is a question that must be answered using appropriate evidence. This is the case whether these individuals have normal colour perception or defective colour perception. But what is the most appropriate evidence that should be collected to answer the question, and how should this evidence be collected? These issues are discussed in the remainder of the paper. AAT decisions in relation to the aviation colour perception standard The informal demonstration in Figures 3 and 4 that colour is neither sufficient nor necessary for appropriate information to be processed from the Airbus A330 ECAM does not provide the kind of evidence allowing proper assessment of the ICAO colour perception standard. Before outlining what such evidence should be, ideally, it is necessary to discuss a more formal and rigorous examination of the ICAO colour perception standard that was carried out by the AAT in Melbourne, Australia some 20 years ago in relation to two separate cases. It is because of the AAT decisions in relation to these cases that moreappropriate evidence, which was not possible to gather at the time of the 12 | JASAM Vol 6 No 1, December 2011 The second comment is to do with two aspects of the evidence provided by the appellants that, on the basis of the AAT’s report, seemed to influence its decisions. (i)The first aspect was the critique of the nature of the empirical evidence used by the Department of Aviation (DOA) and the Civil Aviation Authority (CAA) to support the application of a colour perception standard (e.g., Cole & MacDonald, 19886; MacDonald & Cole, 19887). The essence of this critique was that the empirical evidence had very little to do with measuring the safe performance of the duties involved in flying aircraft, and a lot to do with measuring colour perception performance. Put simply, the empirical evidence put forward to support the application of a colour perception standard in aviation was basically empirical evidence for defective colour perception, and not empirical evidence for defective, or unsafe, aviation. Although the empirical evidence involved many experiments and many different experimental conditions, these experimental conditions could generally be characterised as variations of standard tests of colour perception. And since the participants in this empirical research had all been screened into ’normal’ and ’defective’ groups on the basis of their performance on tests of colour perception, it was inevitable that the participants so grouped would perform differently on the alternative versions of colour vision tests that formed the experimental conditions. (ii)The second aspect was to do with the theoretical approach that underpinned the empirical research used to support the application of a colour perception standard in aviation. This theoretical approach assumed that the information provided to humans by their senses was impoverished and ambiguous. Additional processing was needed before accurate information about the world could be perceived. An alternative theoretical approach to perceptualmotor tasks like flying a plane has been proposed, and was described to the AAT. This alternative approach was set out by James Gibson8 in his 1979 monograph, The ecological approach to visual perception. This alternative approach places more emphasis on the richness of the environmental information available to those engaged in tasks like flying a plane. The first case to be discussed is Pape and the DOA. This case was significant because it was the first time an aviation colour vision standard had been successfully challenged anywhere in the world. The appellant, an author of this paper, a deuteranope, and the holder of a commercial pilot licence and command instrument rating, sought to have removed the limitation placed on his private pilot licence by the DOA that precluded him from piloting aircraft at night. The AAT upheld the appeal, and ruled that the appellant be permitted to exercise the private licence at night with certain extra conditions, namely the carriage of standby radio apparatus and an increase in IFR approach minima. These extra conditions were later removed in the decision given in the second appeal. The second case to be discussed, Denison and the CAA became, by mutual agreement between the parties, a consideration of wider scope than that of Pape and the DOA. It Colour perception standards in aviation involved a wide-ranging investigation of the aviation colour perception standard, and included all types of defective colour perception. The use of colour in larger commercial aircraft, including the use of Electronic Flight Instrumentation System (EFIS) cockpit display equipment was considered, as was the use of colour in the external aviation environment. It is a matter of record that at the close of the hearing phase of Denison and the CAA, all parties agreed that all the evidence available at that point in time had been subjected to exhaustive discussion and scrutiny. The decision of the AAT was to uphold Denison’s appeal, and in setting out the bases of this decision, the AAT made clear its view that defective colour perception did not pose a significant threat to the safe performance of the duties involved in flying aircraft. Consequences of the AAT decisions for an appropriate empirical test of the assumptions underpinning the ICAO colour perception standard A consequence of the AAT decision in the case of Denison and the CAA was that pilots with defective colour perception were able to increase their flying experiences beyond the previously restricted range of such experiences imposed by the aviation colour vision standard. Indeed, pilots with defective colour vision were now able to embark on careers in aviation involving flying modern, large and sophisticated aircraft equivalent to the career paths available to pilots with normal colour perception. Table 1 summarises the flying experiences of two such pilots. Inspection of Table 1 shows that these two pilots have each more than 8000 hours flying experience in a range of sophisticated aircraft. Both have served in command of such aircraft. In addition to the information provided in Table 1 it is instructive to note that the regular flight simulator check and training reports that all pilots operating aircraft at this level of sophistication are required to undertake have been, for these pilots, completed at a very high standard. There have been no questions raised regarding the ”safe performance of duties” of these pilots. 80% 60% 40% 20% 0% Predicted results if argument underpinning colour perception standard is ’false’ 100% Performance on flight simulator Performance on flight simulator Predicted results if argument underpinning colour perception standard is ’true’ 100% Groups Pilots with normal colour perception Pilots with defective colour perception 80% 60% 40% 20% 0% Groups Figure 5. Predicted results of an ideal empirical test of the argument underpinning the colour perception standard. The panel on the left shows the predicted results on the flight simulator if the argument is ’true’; that is, pilots with defective colour perception will perform worse than will pilots with normal colour perception. The panel on the right shows the predicted results on the flight simulator if the argument is ’false’; that is, pilots with defective colour perception will perform the same as will pilots with normal colour perception. A further consequence of the AAT decision is the possibility of the carrying out of empirical research that could provide evidence allowing more-appropriate evaluation of the need for the aviation colour perception standard than had been possible before the AAT decisions. Paradoxically, this includes the evaluation of the AAT itself. This statement should not be seen as a criticism of the AAT, nor of the evidence it considered. Rather, this statement reflects the limitations of the empirical evidence that was available before the AAT decision. This empirical evidence was problematic in two ways. The first problem was that the evidence was not collected from participants who were pilots who differed only in their colour perception abilities. Instead the evidence was typically collected from participants who were not pilots and were selected to take part because they either had normal of defective colour perception. The second problem was that the evidence was not based on measuring the quality of ”performance of duties” involved in piloting aircraft. Instead, as noted earlier, the empirical evidence was based on comparison of performance on quasi-tests of colour perception. The ideal empirical test of the assumptions underpinning the ICAO colour perception standard involves removal of both the problems identified above. An ideal evaluation of the assumptions underpinning the ICAO colour perception standard, and possible results of such an evaluation The ideal empirical evaluation of the assumptions underpinning the ICAO colour perception standard would firstly involve as participants samples of pilots who were representative of the population of pilots to which any empirical results could be properly generalised. These samples of pilots would be matched on some set of variables, but would differ in their colour perception abilities. This difference is the critical variable of interest. It is beyond the scope of this paper to provide details of the variables (e.g., health status, age, etc.) on which the samples of pilots in the proposed research would be matched, except to say that central to this list of matching variables must be the variable of amount and quality of flying experience. Until the AAT decisions, there was little if any opportunity for pilots with defective colour perception to progress in their aviation careers and flying experiences in ways that paralleled the career progress of pilots with normal colour perception. Pilots with defective colour perception were limited in the size and complexity of aircraft they could command, and the conditions under which such command could be exercised. However, with the growth of a cohort of pilots of which the two shown in Table 1 are examples, the possibility now exists for obtaining an appropriate sample of pilots with defective colour perception that match the range of flying experiences achieved by pilots with normal colour perception. In addition to being based on participants that allow proper generalisation of results to the population of pilots, the ideal empirical evaluation of the assumptions underpinning the ICAO colour perception standard must be based on experimental tasks that allow proper generalisation of results to the ”safe performance of duties” in aviation. Part of the critique of the empirical evidence used to support colour perception standards discussed earlier was that this evidence involved experimental tasks that had very little, if anything, to do with the actual task of piloting aircraft. The obvious reply to this critique would be to replace these artificial tasks with experimental conditions that involved the actual piloting of aircraft. Such a proposal is manifestly impractical and inappropriate on numerous grounds. Collecting data during the actual piloting of aircraft would not only be extremely expensive, it would involve exposure of participants to such danger that human research ethics committees would be loath to approve such data collection. What is needed is a task that approximates, as closely as possible, the ”performance JASAM Vol 6 No 1, December 2011 | 13 Colour perception standards in aviation of duties” actually involved in flying aircraft, and does so relatively inexpensively, and without danger to participants. Such a task is available, of course. It is the task of flying an aircraft simulator. This is considered to be so close to what is involved in actually flying aircraft that pilots who fly modern sophisticated aircraft such as the Airbus A330 are required to demonstrate their continuing proficiency and ”safe performance of duties” in aviation by undergoing regular flightsimulator-based assessments. The ideal evaluation of the ICAO colour perception we propose would involve exposing appropriate samples of pilots to a range of experimental tests in a flight simulator. As we said earlier, it is beyond the scope of this paper to provide details of such flight simulator tests and the dependent variables that could be measured. However, we do point out that flight simulators are ideal tools for experimental data collection because flight simulators can be used to expose participants to identical experimental conditions. More importantly, these experimental conditions can involve unremarkable flying situations, and also emergencies of different types forcing participants to use all their abilities, including their colour perception abilities, for the ”safe performance of duties”. The two panels of Figure 5 show the hypothetical and highly simplified results of the ideal evaluation of the assumptions underpinning the ICAO colour perception standard we propose. The results are highly simplified in that the range of possible measures of ”safe performance of duties” in the flight simulator is collapsed into a single measure which we have termed ’Performance on flight simulator’. The panel on the left of Figure 5 shows the predicted results on the flight simulator task if the assumptions underpinning the ICAO colour perception standard are true. Participant pilots with defective colour perception will perform worse than will participant pilots with normal colour perception. The panel on the right of Figure 5 shows the predicted results on the flight simulator task if these assumptions are false. Participant pilots with defective colour perception will perform the same as will pilots with normal colour perception. The pattern of predicted results if the underpinning assumptions are true or false, that is, if the colour perception standard is relevant to ”safe performance of duties” in aviation, are clearly different, enabling a clear evaluation of the need for such a standard. Table 1. Summary of the flying experience of two pilots with defective colour perception who have been able to obtain this experience as an outcome of the AAT decisions relating to the aviation colour perception standard. Pilot 1 Age: 42 Colour perception defect: Protanope References 1. ICAO International Standards and Recommended Practices. Annex 1 to the Convention on International Civil Aviation – Personnel Licensing. 9th ed. July 2001. 2. DOT/FAA/AM-09/11 Office of Aerospace Medicine Washington, DC 20591 “Minimum Color Vision Requirements for Professional Flight Crew, Part III Recommendations for New Color Vision Standards” 3.Memoirs of the Literary and Philosophical Society of Manchester (1798). Dalton, J “Extraordinary Facts relating to the Vision of Colours”. 4.Administrative Appeals Tribunal: Re: ARTHUR MARINUS PAPE and SECRETARY, DEPARTMENT OF AVIATION No. V87/494 AAT No. 3821 Air Navigation (Search at http://www.austlii.edu.au/au/cases/cth/aat/) 5.Administrative Appeals Tribunal: Re: HUGH JONATHAN DENISON and CIVIL AVIATION AUTHORITY No. V89/70 AAT No. 5034 Air Navigation (Search at http://www.austlii. edu.au/au/cases/cth/aat/) 6.Cole, B. L., & MacDonald, W. A. (1988). Defective colour vision can impede information acquisition from redundantly colour-coded video displays. Ophthalmic and Physiological Optics, 8, 198-210. 7.MacDonald, W. A., & Cole, B. L. (1988). Evaluating the role of colour in a flight information cockpit display. Ergonomics, 31, 13-37. 32 8.Gibson, J. J. (1979). The ecological approach to visual perception. Houghton Mifflin, Boston. Deuteranope 8800 hours Flying experience Airbus A320/321 (aircraft flown): Embraer 170 Dash 8 100/200/300 CASA-212 PA-31-350; PA-44 C404, 310/320 Aero Commander 500S Cresco 750 Beechcraft Duke C310/320 Baron Travelair PA44; PA31 Metro 3/23 Saab 340 Boeing 737-300/800 14 | JASAM Vol 6 No 1, December 2011 To make clear the assumptions that underpin the ICAO colour perception standard we set out an analysis of the standard as a logical argument, and identified three assumptions. We discussed problems with the empirical evidence used to support the application of the colour perception standard identified during the AAT consideration of the standard almost 20 years ago. Since these AAT decisions regarding the standard there has emerged a cohort of pilots with defective colour perception yet with extensive experience flying modern, large, and sophisticated aircraft. We argued that these pilots represent a potential pool of participants for a definitive test of the aviation colour vision standard. We proposed that such a definitive test should involve comparison of the ”performance of duties” (to quote the ICAO colour standard) on an appropriate set of flight simulator tasks of two groups of pilots matched on all relevant variables, and differing on the variable of colour perception abilities. We appreciate that carrying out the evaluation we propose would be a complex and expensive undertaking. However, we feel that the effort is warranted because the results of the kind of evaluation we propose would provide the strongest possible basis for the need for and continued application of the colour perception standard, or its removal. Pilot 2 Total hours flown: 8500 hours Flying experience 2005-2007 (recent flight crew status): Command Embraer 170 2007-present First Officer Airbus A320 (preparing for command training) Concluding comments 2006-present Command Boeing 737-800 ORIGINAL ARTICLE Knowledge from the Aviation Industry Adapted for the Management of Victorian Trauma Patients. Melinda Truesdale, MBBS FACEM Grad. Dip. Health Services Management Abstract An assumption underscoring good trauma systems is that the survival from serious injury is enhanced by early recognition of a patient’s risk of early mortality and morbidity. Hence trauma systems attempt to best match the facility’s resources with the patients’ needs. In Victoria, the primary response to a trauma scene is by skilled paramedics. If a patient is within one hour of one of the two adult Trauma Centres the patient will be transferred there, bypassing other Emergency Departments. Otherwise, the patient will be taken to the nearest regional centre, assessed and if major trauma criteria are met, the patient then will be transferred to a Trauma Centre using aero-medical retrieval services. At the receiving Trauma Centre, Trauma Team activation traditionally has been based on physiological criteria, specific high risk injuries and mechanism of injury. Many centres are now looking to a tiered response to trauma to enable them to differentiate between the severely injured patients who have a higher likelihood of an increased mortality than those with a lower mortality. Optimal care of the traumatically injured patient relies on a rapid and prioritized approach to identifying physiological and anatomical derangements that need urgent intervention. ‘Team Training’ originated from principles of Crew Resource Management in the Aviation Industry. At The Royal Melbourne Hospital, Emergency Services regularly run multidisciplinary simulation exercises. This paper will outline the Victorian Trauma System including patient transportation decisions, the criteria of major trauma, the Trauma Team activation and the ‘Team Training’ scenarios. Introduction Trauma is the leading cause of death in the under 40 year old age group. Major trauma is responsible for the loss of more economically productive years of life than heart disease and cancer combined. A review of the Victorian trauma system was undertaken during the late 1990s and a number of deficiencies in the care of trauma patients were identified. The “RoTES Report”1 recommended the development of an integrated system of trauma care, designed to achieve optimal outcomes for trauma patients. In essence, to deliver ‘the right patient to the right hospital in the shortest time’ and ‘to match a facilities resources with a patient’s medical needs so that optimal and cost effective care is achieved.’ Author details A.Prof Melinda Truesdale, MBBS FACEM Grad. Dip. Health Services Management Director Emergency Services, The Royal Melbourne Hospital Senior VMO Emergency Physician, The Royal Women’s Hospital Clinical Associate Professor, University of Melbourne and Monash University Correspondence [email protected] Acknowledgements The author wishes to acknowledge Dr. Jonathan Papson, (Emergency Physician, The Royal Melbourne Hospital) and Ms. Kellie Gumm, (Trauma Programme Manager, The Royal Melbourne Hospital) for supplying some data used in this presentation. An assumption underscoring good trauma systems is that the survival from serious injury is enhanced by early recognition of a patient’s risk of early mortality and morbidity. As a result of the RoTES Report,1 the Victorian State Trauma System evolved. This meant the designation of two state adult trauma centres, (The Royal Melbourne Hospital (RMH) and The Alfred Hospital) or in the case of paediatric patients, The Royal Children’s Hospital. If a patient meets specific pre-hospital trauma criteria it is deemed that the patient needs the expertise of a trauma centre. Therefore, if the patient is within 30 minutes (and often the more liberal time-frame of 1 hour is taken), such a patient will be taken by the ambulance service to the nearest trauma centre and will bypass other hospital emergency departments. The pre-hospital major trauma criteria are summarised as: Glascow Coma Score less than 14; respiratory rate <10 or > 29 per minute; systolic blood pressure < 90 mmHg; Revised Trauma Score less than 11; penetrating injury, mechanism of injury; pregnancy > 20 weeks with evidence of ruptured membranes or foetal distress. (Pregnancies are preferentially taken to RMH due to its co-location with The Royal Women’s Hospital). The trauma patient is then met by the assembled personnel. It was also acknowedged in the “RoTES Report”1 that teams have to form and function efficiently and effectively rapidly. Nearly every time a team involves new members & a new situation each time. ‘Team Training’ was developed to enhance the team function and enable high fidelity education for staff at RMH. Trauma Systems at The Royal Melbourne Hospital Trauma triage seeks to identify and provide rapid treatment of the most severely injured patients and ultimately decrease the time to definitive care and increase the survival rate. Over triage has little impact on the patient, however, it adds significant strain to hospital resources and the state-wide system by decreasing efficiency and effectiveness. It has the potential to devalue the trauma system as a whole due to the “cry wolf syndrome” and unnecessary trauma team activations divert resources away from other hospital activities which could potentially compromise patient care. Many hospitals, which provide trauma care, have developed two-tiered trauma team activation models. These differentiate between the severely injured patients who have a higher likelihood of an increased mortality than those who are less severely injured and therefore usually have a lower morbidity and mortality. The Royal Melbourne Hospital (RMH) assesses 56,000 emergency presentations per year of which nearly two thirds are Australasian Triage System categories one, two, and three.2 There is an even 50:50 split between the two adult trauma centres with respect to the trauma load. With respect to the RMH 2009 financial year, there were 2973 trauma admissions of which 799 were major trauma cases. That averages 66 cases per month or two cases a day. At RMH, Trauma Team activation criteria were developed based on physiological criteria, specific high risk injuries & mechanism of injury.3 It is a two tiered system of ‘Trauma Call’ and ‘Trauma Alert.’ The ‘Trauma Call’ is for the more severely injured patients; involves the full team with a surgeon being immediately being available. The Royal Melbourne Hospital’s Trauma Team consists of a team leader who is either an emergency consultant or senior registrar; a registered nurse (RN) scribe, two senior RNs; airway doctor – (anesthetic registrar or anesthetist); an airway RN; two procedure doctors (includes the surgical registrar); a procedure RN; emergency department assistant (orderly); a radiographer; and, if the patient is pregnant, an obstetrician and neonatal specialist. The ‘Trauma Alert’ is for the less severely injured patients. These patients are JASAM Vol 6 No 1, December 2011 | 15 Knowledge from the Aviation Industry managed primarily by the emergency department team and surgical registrar in consultation with speciality units as needed. Thus the assembled team for an alert is the team leader (emergency consultant or senior registrar), surgical registrar, procedural doctor and RN and a scribe nurse. Surgeons are notified by phone and can attend the department in a short time, should the need arise. In order to improve this environment and potentially refine the criteria, RMH undertook a review and reflection of more than 42,000 ambulance cases in 2008. The guidelines at RMH were modified slightly to reflect these findings. The current ‘Trauma Call’ and ‘Alert’ guidelines are summarised in Tables 1 and 2. Trauma Team Simulation at The Royal Melbourne Hospital The aviation industry learned early on that adverse outcomes occur when teams don’t work well and pioneered the use of simulation for the training of their air and cabin crew with a focus on Crew Resource Management (CRM). Crew Resource Management training was first introduced in the late 1970s as a means to combating an increased number of accidents in which poor teamwork in the cockpit had been identified as a significant contributing factor. Since then, CRM training has expanded beyond the cockpit, for example, to cabin crews, maintenance crews, health care teams, nuclear power teams, and offshore oil teams. Not only has CRM expanded across communities, it has also evolved and benefited from input from multiple disciplines and over the years. In both the aviation and medical environment, teams have to form and function rapidly. This requires team organisation and role clarity. Historically, doctors and nurses train separately but work together. In-situ simulation training began at RMH in 2005. There is medium to high fidelity simulation in former trauma rooms using real equipment. Each course runs for a half day and has between eight and ten participants. It is multidisciplinary: consultants, registrars & nurses (ED, anaesthetics and trauma service). The session begins with a discussion which is titled “Crisis Resource Management”. The aviation context from ‘cockpit’ to ‘crew’ resource management is noted. Coined in 2001 by Gaba,4 the key points with respect to Crisis Resource Management were described as being: the need to know your environment; take a leadership role; anticipate and plan; communicate effectively; call for help early enough; allocate attention wisely and to distribute the workload. The session then moves to discuss the theory of teams, team structure and the role of a team leader and team member. Role clarity is key so that each person identifies him/herself and knows his/her role. Specific cards describing roles are given to the participants to clarify responsibilities. Communication is a focus and it includes discussion about graded assertiveness5. The emphasis for the team leader includes: identification of him/herself as the leader, and introduction and role definitions for other members. Leadership is perceived as an essential component in trauma management.5, 6. No differences were found in the outcome of trauma patients treated by non-surgeon versus surgeon trauma team leaders. Indeed a more collaborative approach to resuscitative trauma management with involvement of non-surgeons as trauma team leaders has been observed.6, 7 The team leader needs to identify and utilise resources; assign group members to particular tasks; let the team members know what is expected; decide what should be done and how; use authority and maintain standards. The leader needs to be able to listen, review and adapt; maintain situational awareness; maintain noise levels and identify and endeavour to solve any team problems. 16 | JASAM Vol 6 No 1, December 2011 Following this initial theory, the group is taken to the simulation area, a former fully equipped trauma room, which is set up with a mannequin and voice over. The group is introduced to the mannequin and its capabilities (such as the ability to take blood pressure, to intubate, to hear breath sounds). The vital signs are able to be set by the session demonstrators and appear on the monitor. The monitor readings in turn can be superimposed on videorecordings which are subsequently used in the debriefing. For the scenario, a case is given to the initial team members present and the ‘patient’ arrives. Other participants wait in an isolated room until called in as needed. The exercise is undertaken in real time, (such as putting in an intravenous line takes a finite time for a particular person). Investigations, (pathology and radiology) need the required request slips to be written and calls to relevant personnel are made using a dedicated phone line. The exercise is videorecorded and the monitor readings are captured on the video simultaneously. The average exercise lasts around 20 minutes and concludes at a logical point in the patient’s care, (such as going in to the CT scanner, to theatre or death of the patient). The group is then taken back to the seminar room for an assisted debrief of the team performance. The facilitator plays pertinent sections of the video back for review and there is group discussion about positive and negative aspects of the patient’s care and the team’s functioning and dynamics. Since team training began at RMH, the participants have been surveyed at the conclusion of each course. The focus of these surveys is on three aspects: the response to environment; the response to the debriefing and other responses. These responses are summarized in Table 3. The advantages of simulation include: routine procedures can be repeated intensively; participants use actual clinical devices; the same scenario can be used on different groups to compare performance; errors can be allowed to occur and be corrected by the participants; simulation can be frozen then restarted to demonstrate alternate techniques; recording and replay can occur without the issue of patient confidentiality. The advantages of in-situ training include learning in one’s own environment which enhances fidelity; the absence of the need to travel to a separate venue; use of clinical devices that will be used in actual cases; a reduction in costs by using date-expired consumables; and the opportunity to test/trial actual systems/new systems); as well as having minimizing the impact of budget costs. Recommendations from the RMH team training experience include: keep the training in the home location (in this case the emergency department); keep it simple; keep it fresh with new case scenarios; keep it multidisciplinary so all members of the team get to work together; keep records of who has partaken and which scenarios were used, and, keep at it! Conclusions The major trauma patient should be taken to the most appropriate hospital in the shortest time. A suitable coordinated & experienced team response should follow. Team training which takes its origins and teaching format from the aviation industry is a powerful learning experience.8, 9. The experience at RMH is consistent with that elsewhere in that participants give strong positive feedback and agree that it enhances their knowledge, teamwork and experience. There is a strong perception from participants that team training in practice has a positive impact on patient care and outcomes. Knowledge from the Aviation Industry References: Table 1: Trauma Call Guidelines: 1.Department of Human Services Victoria: Review of Trauma and Emergency Services – Victoria, 1999 (RoTES Report). Final report of the Ministerial Taskforce on Trauma and Emergency Services and the Department Working party on Emergency and Trauma Services. Respiratory rate < 12 or ≥ 24/min O2 Saturation < 90% Vital Signs Blood Pressure < 90mmHg 2.Australasian College for Emergency Medicine: Australasian Triage Scale. http:// www.acem.org.au/media/policies_and_guidelines/P06_Aust_Triage_Scale_-_ Nov_2000.pdf. Pulse Rate >120 beats/min GCS <9 Penetrating injuries All penetrating injuries to the neck Multiple Patients When 3 or more trauma patients are expected Pregnancy Pregnant patient ≥ 20 weeks gestation with ruptured membranes, PV bleeding, fetal heart rate < 100 bpm Table 2: Trauma Alert Guidelines GCS 9 – 13 4.Gaba DM et al: Simulation-Based Training in Anesthesia Crisis Resource Management (ACRM): a decade of experience Simulation Gaming (2001) June 32 : 2 175-193. 5.Cummings GE, Mayes DC: A Comparative Study of Designated Trauma Team Leaders on Trauma Patient Survival and Emergency Department Length-of-Stay CJEM. 2007 Mar;9 (2):105-10. 6.Hjortdahl M et al : Leadership is the Essential Non-technical Skill in the Trauma Team – Results of a Qualitative Study Scand J Trauma Resusc Emerg Med. 2009 Sep;26;17(1):48. Prolonged loss of consciousness Limb amputation 7.Ahmed JM, Tallon JM, Petrie DA : Trauma Management Outcomes Associated with Nonsurgeon versus Surgeon on Trauma Team Leaders Ann Emerg Med. 2007 Jul;50(1):7-12, 12.e1. Epub 2006 Nov 15. Suspected spinal injury Specific Injuries 3.ATLS. Advanced Trauma Life Support: Program for Doctors. 7th ed. Chicago: American College of Surgeons; 2008. Burns> 20% &/or airway burns Serious crush injuries Major compound fracture or open dislocation Fracture of 2 bones of the tibia, femur, humerus Suspected fractured pelvis Pregnancy Pregnant woman > 20 weeks sustaining trauma Blunt Injuries Obvious severe blunt injury to head &/or torso Penetrating Injuries Penetrating injuries to head &/or torso Inter-hospital Transfers All major trauma transfers to RMH 8.Holzman RS et al: Does team training improve team performance? A meta-analysis. Human Factors: The Journal of the Human Factors and Ergonomics Society (2008) Dec;50 : 903-933. 9.Toff NJ: Human factors in anaesthesia: lessons from aviation Br. J. Anaesth. (2010) 105(1): 21-25. Table 3: Summarised Responses of Participant to Crisis Resource Management training. Response to Environment My responses were realistic The camera didn’t interfere with my performance It was easy to treat the mannequin as a human I felt comfortable in the simulation environment Debriefing Session The session enhanced my knowledge The session added to the learning experience The session clarified important teamwork issues The session clarified important issues with scenario Other Responses The course will help the team function better The course will help me act more safely The course would benefit me as a doctor or nurse The course helps to put teamwork knowledge into practice Agree %* Strongly Agree 58 43 48 59 %* 22 46 17 18 50 42 44 38 48 50 58 55 40 50 23 44 60 40 77 55 *The percentages recorded are only those agree or strongly agree and thus will not add up to 100% JASAM Vol 6 No 1, December 2011 | 17 ORIGINAL ARTICLE THE ADVANTAGES OF A DAME DATABASE Dave Baldwin, BSc, Dip Obs/Gynae, MB, ChB., Dip Avmed, FRNZCGP Abstract Dr Dave Baldwin is a longstanding DAME/AME in New Zealand. He has up to 1800 pilots registered with the Bulls Flying Doctor Service, and has developed a Personal Pilot Medical Database which provides a simple and effective query builder to allow the review of pilot demographics and disease profiles of the pilots registered with his service. A database of this kind has many advantages for DAMEs and for pilots and is a great resource for aviation medicine research. The database The database is based on Borland Delphi™, a relatively simple software package that can be set up to store demographic data, disease information, and flight details for each pilot. It is cheap to set up, and doesn’t need expensive licences and upgrades like larger practice management programs. Figure 1 shows the initial screen. Background Dr Dave Baldwin is a longstanding DAME/AME in New Zealand. His core training is General Practice and Family Medicine, and he practices in the small town of Bulls, located in the lower half of the North Island of New Zealand and situated next door to RNZAF Base Ohakea. He works half time as one of five doctors at the Bulls Medical Centre, a semi-rural General Practice where the workload includes routine family medicine, screening and preventative health, minor surgery (such as vasectomies), and some accident and emergency work. Bulls Medical Centre has been fully computerized for many years, using the MedTech™ practice-management package. In addition to information related to appointments and finances, Medtech™ can easily provide a clinician with data that describes the practice’s patient demographics, disease prevalence, and an overview of screening and health promotion programmes. In addition to working in general practice, Dr Baldwin works half time in aviation medicine. Bulls Flying Doctor Service is based at Palmerston North Airport, and is located in a purpose-built aviation medicine centre which has consulting rooms and classroom facilities (for teaching Massey University Students in aviation medicine, and for various conferences), as well as an administration area and hangar space for its two aircraft: a Cessna XP2 HAWK and a helicopter. These aircraft have been equipped to accommodate all the specialist medical equipment required for an aviation medicine examination. The Bulls Flying Doctor Service performs aviation medical examinations for approximately 1700 pilots, 30% of which have their medical examinations performed at the Palmerston North Airport Aviation Medical Centre. In addition, the Bulls Flying Doctor Service provides a fly-in aviation medicine service to the remaining 70% of pilots on its register. These pilots have their aviation medicals performed at outreach clinics located at regional and rural airports spread across two thirds of New Zealand. These outreach clinics are visited on a regular monthly schedule. Figure 1 For each pilot, the database records the ARN or CAA number, basic demographic data (gender and date of birth), basic aviation data (type of flying, class of licence), and disease codes. The bottom of the screen displays realtime summary statistics: total number pilots, average age, gender mix, total flight hours, and average flight time over the last six months. The disease codes used in the database have been generated by the author. They are intended to identify clients with specific conditions, in order for the clinician to get the casenotes and read through the relevant clinical entries. As such, the disease codes used in this database are not as specific as those used by other clinical management software packages. For example, Figure 2 shows “dyslipidaemia” is segregated into “treated” and “non treated” groups. However, the disease codes are flexible – the DAME can easily add, delete, or modify disease categories as they wish. One drawback to this flexibility in disease coding is that there may be difficulty sharing or comparing datasets between different aviation medical practitioners. The database has very simple but effective sort and search functions. Sorting is done by clicking the heading buttons for each column. Figure 3 shows the data sorted by ascending date of birth. The outreach clinics give the Bulls Flying Doctor Service the opportunity to “live the dream” – get out of the surgery, do mountain flying, and practice aviation medicine in one of the of the most beautiful places in the world. Unfortunately, in contrast to the fully computerised practice at the Bulls Medical Centre, the Bulls Flying Doctor Service had no way to track client demographics or disease prevalence. However, Dr Baldwin has now developed a DAMEspecific database that provides the Bulls Flying Doctor Service with the benefits he sees in his general practice. Author details Dr Dave Baldwin, BSc, Dip Obs/Gynae, MB, ChB., Dip Avmed, FRNZCGP, Bulls Flying Doctor Service Correspondence [email protected] Figure 2 18 | JASAM Vol 6 No 1, December 2011 The Advantages of a Dame Database in New Zealand, spread across approximately two-thirds of the country. As a result, the database that he has created could provide significant insight into the demographic profile and health of New Zealand’s pilots. He intends to undertake a structured review of the clinical and demographic data he has collected in order to better understand the health of his pilots. He would be interested in undertaking collaborative research with other aviation medicine specialists who would be interested in determining the extent to which the dataset he has collected could further our appreciation and understanding of the health of pilots in general, and clinical aviation medicine more broadly. Figure 3 Searching for relevant demographic or disease information is easily performed by entering the search term in the window at the top of each column and clicking the search icon as in Figure 4. Figure 4 The Advantages of Pilot Databases. The author considers that using a database to capture relevant demographic and clinical information for his pilots brings significant advantages, not only to his clinical practice, but also to the service he is able to provide his pilots as well as the potential to create a dataset for aviation medicine research. Advantages for the DAME. The database provides the DAME with evidence-based insight into their aviation medicine practice, enabling the DAME to obtain an accurate profile of their pilot population: the age distribution, gender mix, and the proportion of pilots who fly fixed- or rotary-wing aircraft. The database also allows the DAME to determine the prevalence of particular diseases in their pilot population, and provides them with an understanding of how many of their pilots have hypertension requiring medication, how many have asthma, and how many require spectacles. Furthermore, the author’s experience is that his clinical history and examination has become more meticulous since the introduction of the database, due in part to his understanding that the quality of the results he gets out of the database are only as good as the quality of the data he feeds into it. For example, he would record that a pilot has flown 10560 hours (rather than “about 10 000 hours”), and he now records the method of fixation for a pilot who reports a fracture in the previous 12 months. Figure 5 Advantages for the pilot. Rather than simply performing routine medical examination for pilots to gain medical certification to continue flying, the Bulls Flying Doctor Service provides a “service” to the pilots. The database allows the DAME to provide pilots with ongoing medical advice tailored to their particular demographic or clinical profile. The database makes it easy for a DAME to identify pilots with a particular medical condition, and send them copies of the latest treatment guidelines relevant to their condition. Advantages for aviation medicine research Although New Zealand’s population is relatively small – only 4.3 million people – its disease demographics are representative of many other western countries. The author’s aviation medicine practice covers approximately 18% of all pilots JASAM Vol 6 No 1, December 2011 | 19 ORIGINAL ARTICLE Implantable Cardiac Devices in the Military Aviation Environment Paul Kay, BEng(Hons), PhD, M.IEEE, M.IE Aust Abstract Implantable cardiovascular devices (pacemakers and implantable cardioverter defibrillators) are electronic devices that are implanted in the human body in order to ensure correct operation of the patient’s heart. Malfunction of these devices seriously endangers the patient’s life. In general, electronic devices can malfunction in the presence of radio frequency signals. The engineering endeavour to minimise this problem falls within the discipline known as Electromagnetic Compatibility (EMC). This paper provides an overview of the approach to achieving electromagnetic compatibility with general electronic equipment, then looks at the special case of implantable cardiovascular devices and contrasts the general civilian electromagnetic environment with the military aviation electromagnetic environment. The limits for protection of humans from over exposure to radio frequency energy are compared to the limits for protection of equipment from malfunction due to radio frequency energy. The analysis concludes with the finding that implantable cardiovascular devices in the military aviation electromagnetic environment are at a higher risk of interference than when they are in the general civilian environment. Historical Background: Frogs, Dogs and Electrocardiograms In 1791, Luigi Galvani published his discovery that metallic contact between muscle and the crural nerve in a frog’s leg caused twitching of the muscle; the experiment was replicated by Volta soon afterwards. The ensuing 50 years brought refinements in the generation of electricity and recording of muscle movement as other researchers entered the emerging field of electrophysiology. A laboratory setup of the period is shown in Figure 1. In 1842, Metteucci was able to demonstrate that electrical current was associated with human heartbeat. Measurement of the heartbeat was possible from 1872, when Gabriel Lippmann invented the capillary electrometer; experimenters Sanderson and Page used the apparatus to record two phases of the heartbeat soon afterwards2. Introduction: what is EMC? The International Electrotechnical Committee definition of EMC is “the ability of equipment to function satisfactorily in its electromagnetic environment without introducing intolerable disturbances to anything in that environment.” Note that the definition encompasses the physical properties of the equipment in question as well as the electromagnetic characteristics of the equipment’s operating environment. The environment is defined as the totality of electromagnetic phenomena existing at a given location1. When a piece of electronics can perform its intended function in its intended environment without causing an interference problem, we say that electromagnetic compatibility has been achieved. A familiar example of an electromagnetic interference is the buzzing that is sometimes heard on a desk telephone when a mobile telephone is close by. The buzzing arises because the mobile telephone is transmitting a powerful pulsed signal to the phone tower, and those signals are “picked up” by the desk telephone’s wires (the electromagnetic field induces a voltage between the wires). This unwanted voltage makes its way to the desk telephone’s speaker and an unwanted buzzing occurs, even before the mobile phone rings, because of transmissions that occur when the call is being set up. In the case of a desk telephone, the buzzing is nothing more than a minor annoyance and the interference may be considered to be acceptable – after all, the consequences are minor, and the problem is easily cured by moving the mobile telephone further away from the desk telephone. Figure 1: Galvani’s frog experiment Technological developments over the following hundred years significantly refined our ability to measure electrical activity in the heart. Two streams of research grew: measurement and characterisation of electrical activity in the heart, and electrical stimulation of the heart. The capillary electrometer was supplanted by the electrocardiogram, when Einthoven adapted a galvanometer to the purpose in 1912. The original galvanometer invented by Deprez and d’Arsonval could not measure the very small voltages associated with heart activity; Einthoven’s modifications yielded a very sensitive galvanometer that could respond very quickly to the electrical activity of the heart. An early production version of Einthoven’s apparatus is shown in Figure 2. The patient has both hands and one foot in salt water baths to make electrical contact with the apparatus. The deflections of the moving coil meter must have been very small, evidenced by the viewfinder and magnification apparatus to the right of the detection stage (above the control panel at the centre). The final major technological leap for measurement of the electrical activity in the heart came around 1953 when Dirk Durrer (professor of cardiology at the University of Amsterdam) collaborated with physicist L. H. van der Tweel to apply van der Tweel’s oscilloscope to extracellular cardiograms2. Author details Dr Paul Kay, BEng(Hons), PhD, M.IEEE, M.IE Aust Electromagnetic Test Flight Aerospace Operational Support Group, Development and Test Wing RAAF Base Edinburgh, SA 5111 Correspondence [email protected] Figure 2: Einthoven’s Galvanometer 20 | JASAM Vol 6 No 1, December 2011 Implantable Cardiac Devices Modern ECG machines are digital refinements of the oscilloscope; digital signal processing technology is employed to improve the quality and expand the content of the information gleaned from waveforms present at the ECG’s interface to the patient. Modern software makes the equipment easier to operate and the results are easier to record, store and interpret. However, the measurement philosophy and system architecture of the modern ECG is strikingly close to van der Tweel’s oscilloscope. among them was the idea of an implantable pacemaker. Wilson Greatbach, an electrical engineer, worked with Dr. William Chardack, a surgeon, and implanted a pacemaker in an animal in 1958. An unsuccessful attempt at implanting a similar device in a human patient was made by Dr. Ake Senning in Sweden in the same year, but the device failed after three hours. In 1960, the first really successful implant was performed, and a further 9 patients received pacemakers that year, some of whom lived long and active lives4. Those early devices required a risky surgical procedure in order to attach the electrode to the heart, and mortality was near 10%. Improvements in lead design and insertion methodology pioneered by Dr. Seymour Furman gave rise to a procedure that could be performed under local anaesthetic, without the need for a thoracotomy. Further improvements were produced in 1964, when Barouh Berkovits reported a “demand” pacemaker, which sensed heartbeat in the patient and produced pulses only when necessary. This was a significant improvement over the initial pacemaker designs, which produced pulses irrespective of the patient’s needs4. Figure 3: Modern ECG system Meantime, the first steps towards therapeutic electrical stimulation of the heart were taking place, and two further streams emerged: impulse stimulations, designed to stop fibrillation, and measured low level pacing signals, designed to address heart block. In 1899, Prevost and Batelli stopped ventricular fibrillation in a dog by direct electrostimulation of the exposed heart. In 1947, Beck successfully used the technique in a human patient, and in 1957, the external defibrillator was developed by William Kouwenhoven, an electrical engineer at the Johns Hopkins University in Maryland. This device applied alternating current (AC) externally, using electrodes on the patient’s chest. Cardiologist Paul Zoll applied the external AC defibrillation apparatus to a human patient in 1952. While there was some success with the treatment, the externally applied electrodes caused burns on the patient’s skin. Lown and Neuman improved on that system with their direct current (DC) defibrillator in 1962; this system was more reliable and safer for the patient than the original AC system3. Electrical technology until the 1950s was almost exclusively valve (vacuum tube) based. Miniaturisation was restricted to devices that used very small valves (so-called “peanut valves”, that were approximately the size of a peanut rather than the typical egg sized devices), but such devices were still physically large by today’s standards. Also, power consumption was too high for longterm battery operation, due to the need for a heating circuit in each valve. While it was possible to construct a device as small as a cigarette packet, it was not possible to provide a long life battery small enough to fit inside it. In the mid 1950s at the University of Minnesota, Earl Bakken (co-founder of Medtronic) produced an external pacemaker that used myocardial leads; this device was located outside the body, so the leads had to penetrate the skin to reach the heart, increasing the risk of infection4. Also, the device operated from the AC mains, so was of no use during a power failure. Its main applications were with patients recovering from open heart surgery. With development of the semiconductor transistor in the mid 1950s, the way was opened to many new miniature and low power applications of electronics; Today, implantable cardiovascular devices exist to provide a regular electrical pacing signal to the heart in the event of Sinoatrial node failure (pacemakers) or to apply a defibrillation impulse to the heart in an attempt to stop ventricular fibrillation (cardioverters). In this paper, these devices are referred to collectively as implantable cardiovascular devices (ICDs). Modern ICDs have a range of monitoring and communication functions that allow medical practitioners to interrogate the device from outside the body, to access data relating to the status of the device and the performance of the patient’s heart. Transistors are still used, but not in the discrete form of the late 1950s original transistors; today, millions of transistors reside on a single wafer of silicon, yielding high processing and storage capability with very low power requirements. Electrical Background – Current and Voltage For the purposes of understanding the electrical terms that are used when discussing ICDs, the following terms and analogies may be helpful: Current – this is the movement of charge through a conductor in a circuit. In a hydraulic analogy this may be compared to water flowing along a pipe, a large current may be thought of as a large volume of water issuing from a pipe. Voltage – this is the force that drives a current in an electric circuit; its source can be an assemblage of electric charges (such as inside a battery) or the influence of an alternating current (an external radio wave or electrodynamic field – the effect that allows a radio wave to convert to an electrical signal at an antenna). To continue the hydraulic analogy water may be thought of as flowing through a pipe because a reservoir being at a higher point (electrostatic field) or because of a pump (electrodynamic field). Resistance – this is the property of a material that opposes the flow of current. A substance or component with high resistance will not allow a very large current to flow. In the analogy, a high resistance may be considered to be a small diameter pipe in series with larger diameter pipes connected to a high water tank or pump – even though there is good pressure and good flow for most of the system, the restriction causes a reduction in flow. The key things to remember are that current flows in (or more accurately, on) a conductor and that voltage exists between two points in a circuit. Resistance is a property of materials that opposes current flow – substances with high resistance are insulators (e.g. wood, plastic) and substances with low resistance are conductors (e.g. copper, aluminium). In the case of an external defibrillator, a conductive gel is applied between the skin and the pads to decrease the resistance of dry skin. When considering EMC, it is also necessary to remember some important JASAM Vol 6 No 1, December 2011 | 21 Implantable Cardiac Devices implications of Maxwell’s Equations: • A time varying electromagnetic field (“radio wave”) induces a time varying voltage in a conductor immersed in that field, which then drives a time varying current in this circuit; • A time varying current in a conductor induces a time varying electromagnetic field in the space around it; • A constant current in a conductor produces a static magnetic field near the conductor. Finally, as an aid to understanding mechanisms for radio interference, it is helpful to have an insight into how some radio receivers work. When electronic devices are disrupted by radio signals, the mechanism if often similar to AM radio reception. A radio transmission, such as AM broadcast, consists of a carrier wave that has been modified by superposition of an audio programme. The carrier wave for AM broadcast is around 1000 kHz; numbers such as 729 kHz and 891 kHz will be familiar to some readers. The audio bandwidth (loosely interpreted as “fidelity”) for AM radio is restricted approximately to the range 200 – 4000 Hz. So, the 1000 kHz carrier wave is modified, or modulated, by the much lower frequency audio signal, to form a composite radio signal that has desirable long range propagation properties and embodies the desired audio information. In the radio receiver, it is necessary to capture the radio signal by means of a suitable antenna, then extract the audio components from the radio signal. The latter process is called demodulation, and is achieved with a diode or other non-linear element. The mathematics of a nonlinear operator on the combined radio signal show how the signal is separated into radio and audio frequency components. The interested reader can consult Kawamura et al5 for a summary of the mathematics. Once the composite signal has been broken into its discrete frequency components and products by the non linear element, the audio component is filtered, amplified and relayed to a speaker for conversion into acoustic signals. processing occurring in the leads – they are just bits of wire, albeit very special wire), but they act as antennas and pick up unwanted signals if exposed to an electromagnetic field. The interference arises when wanted signals (i.e. heart impulses) on the leads are combined with unwanted signals (e.g. mobile phone signals) in the ICD, and the ICD has insufficient ability to discriminate between the two. There are two types of leads used with ICDs. Originally, unipolar leads were used exclusively, but in more recent times, these have been almost entirely supplanted by bipolar leads. Bipolar leads are preferred because they make the ICD far less susceptible to interference than unipolar leads. The principle of operation of bipolar input leads is shown in Figure 4. The wanted heart signal is developed between the two parts of the input leads, and is presented to the input of the device as the potential difference between the two leads. An external disturbance, represented by the lightning bolt in the figure, induces more or less the same disturbance on both input leads. At the input to the ICD, a “difference amplifier” (the triangular symbol in the diagram) can be used to subtract the voltage on one lead from the voltage on the other. This has the desirable effect of almost completely cancelling any disturbance that is present on both leads, and leaving only the signals that are the difference between the two leads. The figure also shows a filter, which is a frequency-selective device that allows some frequencies through whilst rejecting other frequencies. It is common for ICDs to incorporate filters that are tuned to reject mobile telephones, while allowing the lower frequency signals associated with the heart to pass through. Implantable Cardiovascular Devices – Physical Arrangement and Radio Frequency properties Implantable cardiovascular devices are embedded in the human body, typically in the upper area of the chest, close to the surface of the skin. The device body houses the battery and processing components, and conductive leads penetrate to the appropriate regions of the heart. The leads, usually around 300mm long, typically perform two functions: • to monitor the electrical activity of the heart in order to detect pulse rate problems (sensing pacemakers) or ventricular fibrillation (cardioverters), and • to deliver the electrical stimulations that are produced inside the device to the conductive pathways on the heart. ICDs operate by monitoring the very small voltages that are associated with heart muscles. Typical sensitivities (that is, detection levels) for ICDs are approximately 0.2 – 3 mV6; the electrical signals that are associated with the heart are comparatively small, so sensitive electronic circuitry is required to detect them. Recall that Einthoven went to considerable trouble to produce a moving coil meter (galvanometer) capable of responding to heart signals. One challenge faced by ICD designers is making the device sensitive to signals produced in the heart, but insensitive to other signals that may exist in the environment. The leads attached to an ICD are the dominant pathway for interference to enter the ICD. No disruptive interference can occur within the leads themselves, because they are electrically passive (that is, there is no amplification or 22 | JASAM Vol 6 No 1, December 2011 Figure 4: Bipolar lead ICD input stage While bipolar leads and difference amplifiers make for a more robust system, it is still possible for strong interfering signals to swamp the system and disrupt operation. If the incoming signals are strong enough to drive the difference amplifier into non-linear operation (analogous to turning a stereo up so loud that it distorts), then the interference cancelling effect is lost, and the amplifier will demodulate radio frequency signals. While the human heart rate broadly lies in the range 0 – 200 beats per minute, which corresponds to something less than 3 beats per second (3 Hz), the ICD’s operating frequency range is determined by the fastest and slowest rise times in the waveforms of the heart. Most ICDs try to process signals in the range 10 Hz to several kHz; higher frequencies can be filtered out without loss of heart signal information. Unfortunately, constructing lightweight, inexpensive filters that perform well across very wide bandwidths (from around 10 kHz to 40 GHz) is very difficult. For that reason, some ICDs incorporate filters that are targeted to the most common, highest risk threats, for example, mobile telephone handsets. Implantable Cardiac Devices Interference Mechanisms Electronic equipment experiences interference when wanted signals are distorted or otherwise corrupted by external electrical influences. Electronic equipment, including ICDs, employs diodes and many other non linear elements to achieve functions that are not associated with radio reception. The interference problem arises when the following criteria are met: 1.the physical nature of the device and any leads attached to it provides an antenna-like function that captures RF signals; 2.sufficiently strong signals reach non linear elements, or overdrive linear elements so that their response is non linear, inside the equipment, and 3.the unwanted demodulated signal in the equipment becomes confused with wanted signals, leading to incorrect operation of the equipment. Criterion (1) is satisfied under most conditions, for most equipment, most of the time. We live in a world where radio frequency signals are ever-present, and any conductive surface (wires, pipes, brackets, plates, etc.) interacts with those fields and has radiofrequency currents flowing on it. Recall that a car radio antenna can be replaced by a wire coat hanger with satisfactory results. Criterion (2) can be satisfied when powerful enough radio transmitters are in close enough proximity to the equipment. The intensity of radio frequency fields can be described by their electric field strength, expressed in Volts per metre (V/m). Table 1 lists some transmitter types, their power and the field strength at various ranges from the transmitter. Note that small transmitters at close range produce higher field strengths than powerful transmitters at long range. To provide some context for Table 1, consumer devices are sometimes designed to tolerate 3 V/m field strength, industrial control systems are designed for around 10 V/m, and safety critical and military equipment is expected to withstand 200 V/m. The author has seen some electronic systems malfunction at less than 3 V/m in laboratory tests. Criterion (2) cannot be satisfied in equipment that does not contain non linear components – so, simple electrical equipment containing ONLY motors, light globes and heating elements are inherently immune to radio frequency disturbances. Table 1: Field Strengths and Distances Transmitter Mobile phone handset VHF aircraft radio 4WD HF (“flying doctor”) radio Peak Power Range Field Strength 0.3 m 25 V/m 1m 7.5 V/m 3m 2.5 V/m 100 m 0.08 V/m 1m 27 V/m 3m 9 V/m 100 m 0.3 V/m 1m 55 V/m 3m 18 V/m 100 m 0.5 V/m 2W 25 W 100 W Finally, interference requires that criterion (3) is satisfied as well. Even if the item’s wiring and structure lends itself to reception of a particular radio transmission, and if the field strength is sufficiently strong to bring about unintentional demodulation in the victim equipment, there may not necessarily be any observable effects. An example of this scenario is a car fuel gauge, exposed to a GSM mobile phone signal (which has a 217 Hz pulse repetition frequency). The property indicated by the gauge (fuel remaining in the tank) varies quite slowly, and the circuits between the sensor and the indicator are designed with this in mind. So slow is the response of the circuit that it may take a minute or more for a gauge to indicate full after the tank has been filled from empty. If such a circuit was exposed to a radio frequency field that induced unwanted impulses of around 200 Hz in it, it is highly likely that there would be no observable malfunction of the indicator. This is because the circuit is incapable of responding to such a fast set of impulses (which, if they represented real inputs from the sensor, would represent the tank being alternately filled and emptied 200 times per second). However, the same set of disturbances in a computer speaker system generally leads to a buzzing sound. In this case, the 200 Hz impulses are within the audio bandwidth that the speakers are designed to reproduce (20 Hz – 16 kHz); the amplifier in the speakers cannot discriminate between wanted and unwanted pulses. Finally, in the case of an ICD, 200 Hz impulses can appear as extra heart beats, possibly causing the ICD to mistake the interference for ventricular tachycardia, leading to an uncommanded defibrillation pulse. RF Immunity of ICDs To reduce the likelihood of EMC problems with ICDs, the US-based Association for Advancement of Medical Instrumentation (AAMI) produced technical standard AAMI PC69, “Active implantable medical devices – Electromagnetic compatibility – EMC test protocols for implantable cardiac pacemakers and implantable cardioverter defibrillators”. This document provides detailed and specific EMC test methods, field strength limits and ICD performance acceptability criteria. These requirements exist in order to specify minimum EMC robustness for ICDs, and to ensure consistency of results between different test facilities. AAMI PC69 was introduced as a draft in 1975, reviewed substantially in 2000, and the subject of further revision in 20078. Technical standards are usually produced by teams of qualified and experienced volunteers operating within the organisational confines of standards production bodies. The AAMI is such a body, and has more than 100 technical committees and working groups that produce or contribute to technical standards for hospital sterilisation, dialysis equipment and general medical electrical equipment (by cooperation with the global International Electrotechnical Committee). At the time of publication of the 2007 version of AAMI PC69, the AAMI Cardiac Rhythm EMC Taskforce of 12 members comprised: Medtronic (4), US FDA (2), Medical Practitioners (3), and Others (3) The evolution of PC69 from 1975 to 2007 is shown in Figure 5. The original version of the standard primarily aimed to protect pacemakers from powerful ship radar systems that operated near 450 MHz. If these radars were energised in harbour, considerable interference issues were observed in the community9. The ensuing 25 years brought new threats in the form of smaller transmitters that could be brought very close to the body, and the year 2000 amendments significantly refined the method and extended the frequency range for measurement. JASAM Vol 6 No 1, December 2011 | 23 Implantable Cardiac Devices Human Exposure to RF Energy The preceding discussions about radio reception and interference highlight the role of non linear elements as accidental demodulators of unwanted signals in victim equipment. Non linear elements respond to the peak of the radio frequency waveform. Figure 5: Evolution of AAMI PC69 1975 – 2007 In 2007, the frequency range for testing was extended again, this time down to DC (0 Hz). This is an unusual requirement among EMC standards, and exists to ensure that the ICD will not inadvertently go into maintenance mode (“magnet mode”). In a clinical environment, a practitioner can use a special probe placed over the ICD to non-invasively interrogate the ICD or upload new pacing programmes. This probe head includes an inductive loop antenna to facilitate data communication with the ICD, and a permanent magnet, whose presence is sensed by the ICD. On detection of a static magnetic field, the ICD changes from normal operation to a maintenance mode that presupposes the presence of the data probe. Unfortunately, the magnetic field produced by a DC current in a wire cannot be distinguished from the magnetic field produced by a permanent magnet, so there is a risk that such ICDs could enter maintenance mode if they are too close to a wire carrying a DC current. In order to protect humans from deleterious health effects due to overexposure to radio frequency energy, government regulators around the world have established regulatory regimes with the intention of limiting exposure. With a few exceptions associated with very high field strength exposure, the main health concern for human exposure is heating of tissue. The amount of heat that is absorbed by tissue corresponds to the average amplitude of the radio frequency source. Figure 6 shows the reference levels for occupational (RF aware workers) and general public RF electric field exposure. Note that the peak levels are very much larger than the time averaged levels. The peak restrictions exist in order to protect against electro-acoustic effects in the human ear, where pops and clicks can be heard in the presence of very powerful pulsed sources, to protect against electrostimulation and to protect against RF shock and burns. The 2007 amendments to PC69 did not extend the frequency range of test above 3000 MHz. The standard justifies the omission based on the following points8: • Radiated fields above 3000 MHz are mostly directed beams that do not cause high intensity public exposure; • Patient and public exposure to such beams is typically low level side-lobes of the antennas; • Devices with a metallic enclosure are expected to provide adequate shielding above 3000 MHz (that is, if a device can meet the lower frequency requirements, it probably has good enough shielding to be robust at higher frequencies as well); • Overlying body tissues have greater shielding effectiveness at higher frequencies. However, recent changes in consumer technology, particularly 5800 MHz cordless telephones and computer networks, are not addressed by the standard in its present form. These systems spread their energy in all directions, and are not directed beams. AAMI PC69:2007 notes that these kinds of emitters will be considered in a future edition of the standard. Figure 6: ARPANSA (Australian Radiation Protection and Nuclear Safety Agency) Standard RPS3 reference levels for RF exposure7. Two very different waveforms can have the same average level, and generate the same heating effect on tissue - a short duration pulse of high peak amplitude produces the same amount of heat as a much lower continuous wave signal. This is important when considering interference to ICDs. The ICD responds to the peak of the interfering wave, because of the response of non linear elements inside it. In contrast, the human body suffers from over exposure mostly due to heating effects, which are related to the average level of the RF signal. It follows that the general protection measures for human exposure are not sufficient to guarantee interference free operation of an ICD – a fact borne out by the numerous RF precautions recommended to practitioners and patients by the ICD manufacturers. To reduce the likelihood of interference to ICDs, device manufacturers provide guidance on how to avoid exposure to radio frequency energy. A list of warnings is shown in Table 2, with some supporting explanation by the author. 24 | JASAM Vol 6 No 1, December 2011 Implantable Cardiac Devices Table 2: RF exposure warnings for ICD patients Electrical reset can be caused by exposure to strong electromagnetic fields (programmed settings may be lost). In this case, the external field couples into the control portions of the device, mimicking a reset command that may be used in a clinical setting, or setting up a fault condition that causes the device to restart. Do not loiter near EAS (Electronic Article Surveillance) systems in shops. This refers to the anti-theft systems that are typically comprised of two loops, one either side of the exit door. The loops transmit a burst of signal intended to illicit a response from the transponder affixed to merchandise. The burst/impulse nature of the transmission could couple to the ICD leads and be mistaken for irregular heartbeats, because of the burst nature of the transmission and the close proximity of the loops to the patient. Do not carry mobile phones in chest pockets and use the ear furthest from the implant when talking. While mobile phones are low powered transmitters, their proximity to the body makes them a significant risk to ICD malfunction (refer to field strengths in Table 1). The table shows that increasing the separation between a transmitter and the victim significantly reduces the field strength at the victim. HF (short wave) diathermy may damage or reset the device. The intent of diathermy systems is to raise the temperature of tissue, using 13.56 MHz or 27.12 MHz RF energy. The coupling to the tissue is usually via an inductive loop antenna that directs the energy in the desired direction. If this intense field was inadvertently directed to the ICD, strong coupling to the leads or the device itself could occur. Damage of semiconductor devices, including ICDs, can occur in cases of extreme overload. Avoid high voltage power lines. There are several reasons for this. First, the lines radiate at the power frequency (50 Hz, or 60 Hz in the US and some other countries). Further, various loads on the supply network bring about harmonic currents which can also radiate, typically up to 350 Hz, but sometimes as high as 2 kHz. Finally, power networks have many switching transients (“one-off” spikes) that could resemble irregular heartbeat if they coupled to the leads. Do not use Magnetic Resonance Imaging (MRI) on ICD patients. The energy levels in this treatment are very high and cannot be selectively directed to one part of the body, so malfunction of the ICD during an MRI process is likely. RF Ablation – keep external defibrillator on standby This process brings high levels of RF energy directly into the heart, in close proximity to the IDC leads. The risk of interference is such that alternate ablation treatments should be considered for ICD patients. Ultrasound – patients should advise the physician before undergoing any treatment. The same comments as HF diathermy apply. Avoid communications equipment. This guidance aims to keep the separation high. Welders and chainsaws are not recommended. Chainsaws, brush cutters and other small petrol engines produce considerable impulsive spark noise from the ignition system. The physical location of the motor is quite close to the torso in normal use and the impulsive spikes could couple into the ICD’s leads. Maintain separation between implantable and electric fences, automotive ignition systems (30 cm) and remote control model transmitters (15 cm). Electric fences produce high voltage impulses at approximately 1 cycle per second, often using a transformer that is much like a car ignition coil. The high voltages, coupled with a large radiating structure (fence) give rise to high peak intensity fields, even though the average intensity is very low. The peaks could appear to the ICD as irregular heartbeats. Modern automotive ignition systems are reasonably well suppressed when in good condition and interference is less likely. However, in both cases, a shock can be received by touching live wires and this could have serious implications for an ICD patient. Remote control transmitters are low powered devices and by keeping a modest separation the field strength is expected to remain below the interference threshold of the ICD. The guidance does not distinguish between the various different types of remote control transmitter now available, but the most powerful types are comparable to a mobile phone handset. JASAM Vol 6 No 1, December 2011 | 25 Implantable Cardiac Devices The Military RF Environment While the assumptions in AAMI PC69 may provide adequate protection in the general community, the RF profile of a military environment is quite different, in terms of the frequencies of transmitters, their proximity to humans, and the peak power. In the military environment, there are numerous radio systems that do not exist in the civilian community. It is possible to meet the maximum RF exposure levels for humans whilst in close proximity to radar transmitters, because the average energy is comparatively lower than the peak due to the very short radar pulse transmission time. To protect electronics from malfunction due to EMC problems, safety-critical military equipment is tested to a very high level (200 V/m) across the range 10 kHz – 40 GHz10. A pictorial representation of the differences between general electronics EMC requirements, PC69 requirements, and high reliability military electronics requirements is shown in Figure 7. The approximate frequency bands of various common transmitters are also shown, but there is no indication of the relative powers of these transmitters in the figure. at very close spacing (1.3cm). This setup captures the inductive coupling effect of a mobile phone close to the body, but is not directly comparable to the free space field strengths of other standards. Conclusion An introduction to interference mechanisms has been provided. Considerable engineering effort is expended in producing ICDs that are robust in the face of various radio frequency disturbances, but the challenge is great. Many of the preferred interference mitigation measures are not practical for a device that must be implanted in the body. Further, there is a need to balance the susceptibility of the ICD to interference against the correct therapeutic sensitivity setting: it has been shown that ICDs are more susceptible to interference at their most sensitive setting6, but that must be a secondary consideration to therapeutic efficacy when choosing a level. The central change in terms of human safety from radiofrequency disturbances when an ICD is introduced to the body is that the patient’s life is now susceptible to peaks of radiofrequency energy, because that is the susceptibility of the electronic circuit that sustains their heart function. Human exposure to radiofrequency energy in the general community is low compared to the military environment, but even so, ICD patients must take numerous precautions to avoid exposing the device to various disturbances, particularly impulsive ones (mobile phones, spark ignition, commutator electric motors). Acknowledgment The author acknowledges the support of the Aerospace Systems Engineering Squadron and the Institute of Aviation Medicine of the Royal Australian Air Force’s Aerospace Operational Support Group. References 1.IEC 61000-1-1 (ed. 1.0) “Electromagnetic compatibility (EMC) Part 1: General Section 1: Application and interpretation of fundamental definitions and terms”, IEC Apr. 1992. 2.Rosen MR, Janse MJ. “Electrophysiology: from Galvani’s frog to the implantable defibrillator”, Dialogues in Cardiovascular Medicine, Vol. 11, No. 2, 2006. Figure 7: RF environments, sources and EMC test levels Inspection of Figure 7 shows that the RF immunity test levels for general consumer and industrial electronics are quite low, at 10 V/m or less. Further, they are restricted to a comparatively small frequency range, 80 MHz to 2000 MHz, although this requirement is often supplemented by a complementary test in the range 150 kHz to 80 MHz. The pink horizontal line is the peak test level in MIL STD 461F for safety critical military electronics, 200 V/m. This is a very demanding test to perform and requires a complex laboratory setup. The orange arrow in the figure shows the shortfall between the MIL STD 461F test level and the maximum peak exposure allowed for humans. Equipment that has been tested to 200 V/m must be provided with supplementary shielding in order to tolerate the peak human exposure environments. In contrast, the immunity requirements for electronic equipment located inside the cabin of a passenger aircraft is approximately 5 V/m in the range 100 – 8000 MHz11. The test levels for PC69 are not shown on the graph because the test methodology of that document does not provide a field strength level that is directly comparable to other EMC standards. The PC69 methodology uses a setup that emulates the effect of a hand-held emitter at a distance of 15cm, and an optional characterisation in the standard emulates mobile phone devices 26 | JASAM Vol 6 No 1, December 2011 3.“Defibrillator and cardioverter – Early defibrillators”, Medical Discoveries, retrieved from www.discoveriesinmedicine.com/Com-En/Defibrillator_and_Cardioverter.html on 21st Jan 2011. 4.Greatbach W, Holmes CF. “History of Implantable Devices”, Engineering in Medicine and Biology Magazine, IEEE, Vol. 10, Issue 3, Sept. 1991, pp 38-41, 99. 5.Kawamura Y, Futatsumori S, Hikage T, Nojima T, Koike B, Fujimoto H, Toyoshima T. “A Novel Method of Mitigating EMI on Implantable Medical Devices: Experimental Validation for UHF RFID reader/writers”, IEEE Symposium on Electromagnetic Compatibility, Austin, Texas, 2009, pp 197 – 202 6. Hille S, Eichorn KF, Gonschorek K-H. “Interference Voltage and Interference Threshold in Pacemakers with Unipolar and Bipolar Electrodes”, IEEE Symposium on Electromagnetic Compatibility, Austin, Texas, 2009, pp 147 – 152 7.Radiation Protection Standard Maximum Exposure to Radiofrequency Fields – 3 kHz to 300 GHz, Radiation Protection Series No. 3, Australian Radiation Protection and Nuclear Safety Agency, Commonwealth of Australia, 8th May 2003 8.Active implantable medical devices – Electromagnetic compatibility – EMC test protocols for implantable cardiac pacemakers and implantable cardioverter defibrillators, American National Standards Institute, Arlington, VA, 12th April 2007 9.Kay P, Garrett R. “EMC Standards Development in Australia”, IE Aust EMC Society of Australia Symposium on Electromagnetic Compatibility, Melbourne, Australia, Sept. 2010. 10. Department of Defense interface standard requirements for the control of electromagnetic interference characteristics of subsystems and equipment, MIL STD 461F, US Dept. of Defense, 10th Dec. 2007 Reprint R U R A L of AN D R EM O T E Royal H EA L T H Frequent users the Flying Doctor Service primary clinic and aeromedical services remote Wales: a quality study equentin users of the New RoyalSouth Flying Doctor Service primary clinic and David Lservices Garne, MBChB, MIPH(Hons), A Perkins, BA(Hons), PhD, Frances T Boreland BA(Biol)(Hons), eromedical in DCH, remote NewDavid South Wales: a quality study MPH(Hons) and David M Lyle MB BS, PhD, FAFPHM Abstract David L Garne, David A Perkins, Frances T Boreland and David Lyle ThereMare several different models of general practice in Australia, and one interesting variant is the Royal Flying Doctor Service of Australia (RFDS), a Objective: To examine patterns of the Royal Flying Doctor Service of here are several different modelsactivity of ABSTRACT community-based not-for-profit organisation. The South Eastern Section is one of general practice in (RFDS) Australia, Australia in far and western New South Wales and to determine whether four operational sections of the RFDS Australia-wide, and the Broken Hill base is this Objective: To examine activity patterns of the Royal Flying Doctor Service 1of Australia one interesting variant the Royal frequent use ofis RFDS services, (RFDS) particularly emergency evacuations, is a useful corporate headquarters. It employs a core clinical workforce consisting in far western New South Wales and tosection’s determine whether frequent use of RFDS Doctor Service of Australia indicator of patients(RFDS), who may benefit fromparticularly care planning and review. practitioners flight who nurses, as well as child and family nurses, services, emergency evacuations, isofageneral useful indicator of and patients may munity-based not-for-profit organisawomen’s health practitioners and mental health workers.2 They run primary care benefitWe from care planning and review. Design,Section setting isand conducted a retrospective audit of The South Eastern oneparticipants: of clinics, conduct remoteaudit telephone consultations, respond to medical emergencies Design, anddatabase. participants: conducted a retrospective of the RFDS South the RFDS Eastern Section’s Brokensetting Hill patient PatientsWe with a perational sections of South the RFDS AusEastern Section’s Broken Hill patient database.and Patients with a residential address in theSection works cooperatively with manage aeromedical evacuations. The residential address in the study area who had accessed at least one RFDS medical wide, and the Broken base isISSN: this The Medical Journal of Hill Australia study area who had accessed at least one RFDS medical service between July 2000 and 1 state-based health services and1the local community-controlled Aboriginal Health n’s corporate headquarters. It service between 1 July 30 June 2005 were included in the study. 025-729X 7/21 December 2009 1912000 11/ and 30 June 2005 were included in the study. Service to provide a wide range of primary health care and specialist services to ys a core clinical workforce consist2 602-604 Main outcome measures: Number Main outcome measures: Number of evacuations, consultations andsettlements remote in far western New South Wales and of evacuations, clinic consultations and remoteclinic communities and smaller f general practitioners and flight ©The Medicalremote Journalconsultations; of Australia 2009 consultations; usagenumber by frequent evacuees; number of primary diagnoses recorded clinic usage by frequentclinic evacuees; of primary associated cross-border regions in Queensland and South Australia. , as well as child and family nurses, www.mja.com.au for evacuees; frequent evacuees; frequent diagnoses for frequent number ofnumber frequentofusers who users who might benefit from multidisciplinary n’s health practitioners and mental Rural and remote health recorded care or specialist shared care. The question of how the RFDS might evaluate the quality of its clinical care has might benefit from multidisciplinary care or specialist shared care. workers.2 They run primary care Results: Between July 2000 and June 2005, thebeen number of residents requiring the subject of a review by the evacuation South Eastern Section. , conduct remote telephone consulResults: Between July 2000orand Juneconsultations 2005, the number of by residents remote declined 26% and 19%, respectively, and the number of , respond to medical emergencies Onethe method examining quality is toofstudy requiring evacuation or remote consultations declined by declined 26% andby19%, residents accessing clinics 6%. (Over samefor period, the population the frequent attenders at a clinic anage aeromedical evacuations. The or service. This approach has been applied study area fell by about 24%.) Of theby786%. patients who were identified as frequent users of in both general practice and respectively, and the number of residents accessing clinics declined n works cooperatively with state- the evacuation service ( 3 evacuations/year), 34 emergency department settings.3-7 We hypothesised that such patients may had three or more primary diagnoses (Over same period, the population of the study area fell by about 24%.) Of health services andthethe local commurecorded; 15 were infrequent or non-users of the clinics ( 3 attendances/year); 53 may and may benefit from a care have conditions that were not well managed the 78 patients who were identified as frequent users of the evacuation service ontrolled Aboriginal Health Service have benefited from multidisciplinary care, and 41 from specialist shared care. planning or review process. Our aim was to determine whether frequent use 3 evacuations/year), 34 had three or more primary diagnoses recorded; 15 vide a wide (≥ range of primary health Conclusions: Simple, practical clinical review systems can help healthevacuations, care organisations in as a flag to identify patients of services, particularly could serve infrequent or non-users of the clinics (≥ 3 attendances/year); 53 may nd specialist were services to remote com- rural and remote communities to achieve better outcomes by identifying patients who whose care should be reviewed. have benefited from multidisciplinary care, and 41 from specialist es and smaller settlements in far may benefit from planned care.shared care. n New South Wales and associated We report on the usage patterns of RFDS services in remote NSW, the Conclusions: Simple, practical clinical review systems can help health care MJA 2009; 602–604 border regions in Queensland and characteristics of patients who are191: frequent users of clinic and aeromedical Australia. organisations in rural and remote communities to achieve better outcomes by services, and the implications for delivery of quality clinical care. may benefit from planned care. question ofidentifying how thepatients RFDSwho might consisted of residents of remote communi1 Geographic region of the study te the quality of2009; its clinical care has ties in far western NSW served by the MJA 191: 602–604 1 Geographic region of the study population (shaded), population (shaded), showing he subject of a review by the South Broken Hill RFDS base, who had accessed showing relevant local government relevant local government areasareas n Section. at least one RFDS medical service (evacumethod for examining quality is to ation to a hospital, clinic consultation or frequent attenders at a clinic or remote consultation) between 1 July 2000 Unincorporated Far West e. This approachAuthor has beendetails applied in and 30 June 2005. The area served by the Bourke general practice and emergency David L Garne, MBChB, DCH, MIPH(Hons), Broken Hill RFDS base includes all of the 3-7 ment settings. We hypothesised Central Darling Shire, all of the UnincorpoDirector of Clinical Medicine Stream,1 and Senior uch patients may have conditions that rated Far West region, and parts of the Medical Officer (Education and Research)2 r not well managed and may benefit Bourke, Cobar 3 and Wentworth shires (Box ve David A Perkins, BA(Hons), PhD, Director Ri a care planning or review process. 1). We excluded residents of the city of g n Frances Twhether Boreland,freBA(Biol)(Hons), MPH(Hons), rli im was to determine Broken Hill and visitors to the region Da Officer,evacuPrimary Health Care Research, Broken Hill use of services,Research particularly Cobar because the RFDS is not responsible for Evaluation Development Program3 could serve as a flag and to identify providing their primary health care. The David be M Lyle, MB BS, PhD, resident FAFPHM, population Head1 ts whose care should reviewed. Central Darling of the study area was report on the1 D usage patterns epartment of RuralofHealth, University of Sydney, Hill, NSW. determined from the Broken 2001 and 2006 censervices in remote NSW,Flying the charac2 Royal Doctor Service Australia susesof(Box 2).8,9 (South Eastern Section), cs of patients whoBroken are frequent users Hill, NSW. Data extracted from the patient database ic and aeromedical services, and theHealth Research, Department of Rural Health, Wentworth 3 Centre for Remote were the patient’s unique identifier, age, sex, ations for delivery of quality clinical University of Sydney, Broken Hill, NSW. postcode of residence, date of consultation, service type (evacuation, clinic consultation Correspondence or remote consultation) and diagnosis HODS (International Classification of Primary Care [email protected] nducted a retrospective audit of the [ICPC] code for diagnoses made in the clinic South Eastern Section’ s Brokenwith Hill permission or remote consultation setting, and InternaReproduced t database. The study population tional Classification of Diseases, 10th reviGame DL et al. Frequent users of the Royal Flying Doctor Service METHODS primary clinic and aeromedical services in remote New South Wales: MJA • Volume 191 Number 11/12 • 7/21 December 2009 We conducted a retrospective audit of the RFDS South Eastern Section’s a quality study. MJA 2009; 191:602-604. ©Copyright 2009. The Broken Hill patient database. The study population consisted of residents of Medical Journal of Australia – reproduced with permission. remote communities in far western NSW served by the Broken Hill RFDS base, who had accessed at least one RFDS medical service (evacuation to a hospital, clinic consultation or remote consultation) between 1 July 2000 and 30 June JASAM Vol 6 No 1, December 2011 | 27 Frequent users of the Royal Flying Doctor Service clinics attended by a frequent evacuee was 34. 2005. The area served by the Broken Hill RFDS base includes all of the Central Darling Shire, all of the Unincorporated Far West region, and parts of the Bourke, Cobar and Wentworth shires (Box 1). We excluded residents of the city of Broken Hill and visitors to the region because the RFDS is not responsible for providing their primary health care. The resident population of the study area was determined from the 2001 and 2006 censuses (Box 2).8,9 Almost half the patients who were evacuated three or more times (34/78) were identified as having three or more primary diagnoses, and the majority of these were identified as having conditions that could benefit from multidisciplinary primary care (53/78), specialist shared care (41/78), or both (Box 5). Some patients with two or more primary diagnoses required multidisciplinary care for one condition and shared care for another. 2 Population data for the study area,* by local government area Local government area 2001 2006 Change (%) census data census data Central Darling (all) 2385 1937 - 18.8 Unincorporated Far West (all) 1607 1122 - 30.2 Bourke (part) 622 389 - 37.5 Cobar (part) 97 63 - 35.1 Wentworth (part) 621 552 - 11.1 Total 5332 4063 - 23.8 The top five clinic diagnostic categories (ICPC system) for the 23 patients who attended 13 or more clinics and were evacu•ated three or more times were circulatory (13), endocrine, metabolic/nutritional (9), psychological (5), respiratory (5) and diges•tive (4). The top five evacuation diagnostic categories (ICD-10 system) for this group were circulatory (12), genitourinary (4), res•piratory (4), neoplasms (3), and mental/behavioural, injury and nervous (2 each, in equal fifth place). DISCUSSION In spite of a fall in the population served during the period of the study, demand for the RFDS remained strong, albeit with an unexplained dip in evacuations in 2004–05. * Population within New South Wales served by the Broken Hill base of the Royal Flying Doctor Service South Eastern Section. Data extracted from the patient database were the patient’s unique identifier, age, sex, postcode of residence, date of consultation, service type (evacuation, clinic consultation or remote consultation) and diagnosis (International Classification of Primary Care [ICPC] code for diagnoses made in the clinic or remote consultation setting, and International Classification of Diseases, 10th revision [ICD-10] code for diagnoses of patients evacuated to a hospital). The decline in clinic attendances was largely caused by a reduction in attendances per patient rather than a substantial reduction in the number of patients seen. The majority of patients who were frequently evacuated had chronic health conditions and might benefit from living closer to secondary or tertiary health care. However, by choice or circumstance, they are living in isolated settings. Given the relative lack of specialist and subspecialist services in rural and remote Australia,10,11 the RFDS is an important provider of primary health care to the local population. Other factors such as lower income levels, poorer socioeconomic conditions, a higher proportion of Indigenous people and the fact that men in rural communities are less likely than their metropolitan counterparts to use preventive health services compound these issues.12 The frequency of evacuations for a patient in each 12-month period (July to June) was grouped as once (one evacuation), twice (two evacuations) or frequent (three or more evacuations). The frequency of patients accessing the clinic service in each 12-month period (July to June) was classified as low usage (1–3 consultations), medium usage (4–12 consultations) or high usage (13 or more consultations). RESULTS Between 2001 and 2006, the estimated resident population decreased by 24% (Box 2). The number of residents requiring evacuation or remote consultations between July 2000 and June 2005 declined by 26% and 19%, respectively, whereas the number of residents accessing clinics remained relatively stable, declining by only 6% (Box 3). Most patients requiring frequent evacuation had two or more primary diagnoses and conditions that would normally require multidisciplinary or specialist shared care, and some required both. This suggests that those who require frequent evacuation may have unmet health needs, poorly managed chronic diseases of the sort usually managed in general practice, or comorbid conditions that may benefit from shared care between generalist and specialist providers or multidisciplinary teams. Data on frequent users of the evacuation service and the number of times they presented for clinic consultations are shown in Box 4. Of the 78 patients who required frequent evacuation, four did not attend clinics at all, a further 11 attended 1–3 times, and almost a third (23/78) attended 13 or more clinics during the year. No patient was recorded as a frequent user of evacuation services in more than one 12-month cycle. The maximum number of evacuations required by a patient was seven, and the maximum number of Almost a fifth of patients requiring frequent evacuation were infrequent users or non-users of the clinics. The Royal Australian College of General Practitioners has suggested that one way to target patients requiring preventive health care is to proactively identify high-risk individuals who may be infrequent users of primary health care,12 and one of the Australian coordinated care trials showed that the greatest benefit was experienced by patients who were not previously linked with services.13 3 Usage pattern of services, by service type, July 2000 to June 2005* Service type 2000–01 2001–02 2002–03 2003–04 2004–05 Change between 2001 and 2005 (%) Evacuations 268 (354) 274 (345) 268 (336) 252 (340) 198 (256) –26.1 (–27.7) Clinic consultations 2787 (10829) 2756 (10526) 2724 (9943) 2654 (8830) 2612 (8903) –6.3 (–17.8) Remote consultations 1782 (3430) 1668 (3252) 1663 (3252) 1557 (2993) 1446 (2564) –18.9 (–25.3) 3217 (14613) 3201 (14123) 3166 (13531) 3107 (12 163) 3012 (11 723) –6.4 (–19.8) Total † † † † † * Figures represent number of patients (number of encounters). †Some patients accessed more than one service type during the designated period. 28 | JASAM Vol 6 No 1, December 2011 Frequent users of the Royal Flying Doctor Service If infrequent clinic users with poorly managed conditions are to receive the best quality care, the RFDS service model currently operating in far western NSW will need to be modified. Best-practice, comprehensive and continuous care implies that the RFDS should adopt care pathways and protocols that include multidisciplinary assessments by doctors, allied health staff and, where appropriate, medical specialists.14 These assessments, supported by case conferences (if necessary), should lead to agreed care plans and multidisciplinary or shared care with clear responsibilities for implementing, monitoring and initiating timely reviews. The evacuation of a patient should act as a trigger for a multidisciplinary assessment, which may lead to a care plan or shared care arrangement. The RFDS should also regularly review evacuations and patients with high clinic attendance to see if the most appropriate service is being provided to those patients, taking account of the difficulties imposed by location and personal circumstances. RFDS patients may need to travel to regional centres or capital cities to access medical specialists, and waiting times for non-urgent appointments may be a problem. Travelling to attend a specialist appointment may incur costs such as lost earnings and may disrupt family or community responsibilities. Problems of distance and low population density mean the RFDS will have to continue using a combination of approaches, including face-to-face consultations, phone calls and videoconferencing, to enable primary and secondary consultations, care planning and shared care for its patients in remote areas. The RFDS has already had to redefine its traditional role as a provider of bush clinics and emergency evacuations to encompass comprehensive primary health care based on a multidisciplinary workforce, strong partnerships with other providers and a strong population health perspective. 4 Clinic attendance pattern among frequent users of the evacuation service, July 2000 to June 2005* Clinic 2000–01 2001–02 2002–03 2003–04 2004–05 attendances Total 0 0 0 1 2 1 4 1–3 4 1 3 0 3 11 4–12 11 6 5 11 7 40 >13 6 4 4 5 4 23 Total 21 11 13 18 15 78 *Figures represent number of patients requiring frequent evacuation (>3 evacuations per year). 5 Number of primary diagnoses recorded for frequent users of the evacuation service, by number of clinic attendances, and potential need for multidisciplinary care or specialist shared care, July 2000 to June 2005* Clinic attendances Three Needs or more multiprimary disciplinary diagnoses care One primary diagnosis Two primary diagnoses 0 2 1 1 1 1–3 3 5 3 4–12 10 16 >13 5 Total 20 Needs specialist shared care CONCLUSION People living in remote communities generally have less access to health care and make less use of services. Further development of practical and manageable assessment, care planning, and multidisciplinary and specialist shared care delivery systems will help the RFDS to achieve better outcomes for patients. The frequency of service use, particularly emergency evacuation, is a simple tool for identifying patients who may benefit from assessment and review. ACKNOWLEDGEMENTS We would like to acknowledge the contributions of Gary Oldman (RFDS Broken Hill), who assisted with providing patient data, and Robert Williams (RFDS National Office), who reviewed an earlier draft. The University of Sydney’s Department of Rural Health at Broken Hill is funded by the Australian Government Department of Health and Ageing. COMPETING INTERESTS None identified. REFERENCES 1.Royal Flying Doctor Service of Australia. Our divisions. http:/www.flyingdoctor.org. au/About-Us/Organisation-Structure/(accessed Apr 2009). 2.Royal Flying Doctor Service of Australia. South Eastern Section. Our services. http:/ www.flyingdoctor.org.au/Health-Services/(accessed Apr 2009). 3.Smits FT, Brouwer HJ, van Weert HC, et al. Predictability of persistent frequent attendance: a historic 3year cohort study. Br J Gen Pract 2009; 59: 114-119. 4.Neal RD, Heywood PL, Morley S, et al. Frequency of patients’ consulting in general practice and workload generated by frequent attenders: comparisons between practices. Br J Gen Pract 1998; 48: 895-898. 5.Vedsted P, Christensen MB. Frequent attenders in general practice care: a literature review with special reference to methodological considerations. Public Health 2005; 119: 118-137. 6.Brandon WR, Chambers R. Reducing emergency department visits among highusing patients. J Fam Pract 2003; 52: 637-640. 7.Hansagi H, Olsson M, Sjöberg S, et al. Frequent use of the hospital emergency department is indicative of high use of other health care services. Ann Emerg Med 2001; 37: 561-567. 8.Australian Bureau of Statistics. Census of population and housing. Canberra: ABS, 2001. 9 Australian Bureau of Statistics. Census of population and housing. Canberra: ABS, 2006. 10.Australian Institute of Health and Welfare. Rural, regional and remote health: indicators of health system performance. Canberra: AIHW, 2008. (AIHW Cat. No. PHE 103; Rural Health Series No 10.) 11. Australian Government Productivity Commission. Australia’s health workforce. Research report. Melbourne: Productivity Commission, 2005. http://www.pc.gov. au/projects/study/healthworkforce/docs/finalreport (accessed Jul 2009). 12.Royal Australian College of General Practitioners. Guidelines for preventive activities in general practice. 7th ed. Melbourne: RACGP, 2009. 13.Battersby MW. Health reform through coordinated care: SA HealthPlus. BMJ 2005; 330: 662-665. 3 14.Wagner EH, Austin BT, Von Korff M. Organizing care for patients with chronic illness. Milbank Q 1996; 74: 511-544. 7† 6† (Received 17 Apr 2009, accepted 27 Aug 2009) 14 27 † 16† 2 16 18† 16† 24 34 53 41† † *Figures represent number of patients requiring frequent evacuation (>3 evacuations per year). †Some patients with more than one major diagnosis require both multidisciplinary care and shared care. JASAM Vol 6 No 1, December 2011 | 29 2010 DINNER PRESENTATION How to earn a golden caterpillar AVM Eric Stephenson AO OBE As presented by AVM Eric Stephenson at the 2010 Gala Dinner held at Australian War Memorial, Canberra. It is very special to be having dinner alongside the venerable ‘G for George’ Lancaster bomber that was never shot down in all its 89 missions over enemy territory. It was mainly crewed by Australians and was brought here to be displayed in Aircraft Hall. I happened to be driving along Northbourne Avenue so of course, I followed the large trailer with its load of Lancaster into the War Memorial when Canberra Times photographers were waiting to record the event. (Photo 8). The crew of ‘G for George’ which changed from night to night never had to bail out using their Irvin chutes so none of them qualified to join the Caterpillar Club when flying in ‘G for George’. The Irvin Parachute Company, originally in the USA, was established in England in 1920 by Les Irvin and he also started the Caterpillar Club for people who had jumped from a disabled aircraft and whose life was saved by an Irvin parachute. He gave a small gold pin in the shape of a caterpillar to every member and if the member jumped from a burning aircraft his pin has red eyes. (Photo 9) There are no meetings or membership fees and there are now about 4000 members of all nationalities. Over the years there have been about 100,000 people whose lives were saved by Irvin parachutes. Caterpillar refers to the little creature that spins the silk threads from which the original parachutes were made and the fact that the caterpillar or silkworm lets itself down to earth by a silken thread. This gave rise to the club motto: “Life depends on a silken thread” is the club’s motto. No, of course, parachutes are made of nylon. night of Thursday December 16 1943, the night we have just seen and heard when a total of 54 Lancasters were lost, 29 of them on the way home or trying to land in the appalling weather conditions at their home bases (photo 2). The weather hadn’t been too bad when we left our base at RAF Spilsby in Lincolnshire that afternoon. Spilsby was a rather dreary base of Nissen huts and duck boards like the majority of bases in Lincolnshire in the 1940s. Lancasters had a crew of seven – pilot, navigator, bomb-aimer, flight engineer, wireless operator, mid-upper gunner and rear gunner. I was the navigator. (Photo 3) After breakfast on Thursday December 16th we went as usual to the crew room to see whether operations were on that night. They were. Briefing was after lunch so the seven of us attended the General Briefing under close security, discovered Berlin was again the target and were now forbidden to use a telephone for off base calls and forbidden to go our own quarters. We attended specialist briefings for individual crew members and, as navigator, I collected a large bag of instruments and maps. Then we returned to our crew room to don flying gear. This consisted of long, warm underwear, battle dress, Mae West flotation jacket, parachute harness and, of course, a parachute. The two gunners also collected special heated suits which they could plug into the fuselage of the aircraft to access the electricity supply that was generated by the four engines. The gunners could not move about the aircraft like the rest of the crew and it must be remembered that at an operational height of 20,000 feet or more the temperature could be -20°C or less. While we were preparing for our mission our bombs were being load into our aircraft. (Photo 4) We also collected ”flying rations” as we would be airborne for six hours or more. We were then ready to be driven to dispersals for take-off at about 4:30 p.m. When we arrived at our aircraft (P for Peter) all seven of us climbed up the small ladder into the rear of the fuselage, the two gunners going into their turrets and the remaining five of us climbed over the main spar which went from wing tip to wing tip and which contained all the aviation fuel for the mission. The pilot, flight engineer and bomb aimer went to the nose of the aircraft and the wireless operator and I went to our workstations on the port side of the fuselage. There was a curtain around our area to screen us from the rest of the aircraft because we had to work with lights. When we were told by the control tower, ”Start engines” the noise from four Merlin engines was deafening and the only way for crew members to communicate was by intercom. Photo 1 – AC2 aircrew cadet Scarborough March 1942 I became eligible to join the Caterpillar Club on the Photo 2 – The author March 1943 Photo 3 – Lancaster bomber crew 30 | JASAM Vol 6 No 1, December 2011 How to earn a golden caterpillar I pulled back the curtain screening me from the rest of the cabin and saw the pilot, Ralph Allen, and the engineer getting ready to go down the stairs into the bomb aimer’s area to bail out. Ralph saw me and beckoned me furiously to follow them. His intercom had been shattered I later learned. I grabbed my parachute, clipped it onto the harness and then realised the wireless operator, sitting next to me was still attending his radio. I thumped him on the shoulder, pointed to my ‘chute and yelled ”Bail Out” in his ear. By this time, our Lancaster was in a spiral dive and it was difficult to move, let alone walk about, but I managed to get to the aircraft nose, leapt down the stairs and dived headfirst through the escape hatch into the cold night air. This was NOT the way we had been told to do it but then we had never actually practised the procedure. Photo 4 – Lancaster bomb load with 4000 lb ’cookie’ Once airborne, aircraft from about 35 bases in Lincolnshire flew across the North Sea to rendezvous at a point near the Dutch coast and then set course for Berlin. Our aircraft had a special mission on this trip. We had an infrared camera installed to take photos of the total damage done to Berlin industries and to do this, we were located in the last wave in the bomber stream with instructions to fly straight and level for 29 seconds after dropping our bombs. Photo 5 – Lancaster loaded bomb bay When we reached the target area, we could see huge areas of fire. Target markets dropped by RAF Pathfinder Force showed the bomb aimer where to drop our 4000 pound ”Cookie” and smaller bombs (photo 5). He did this and called “Bombs gone” over the intercom. While we were flying straight and level to take our photographs, an electronic device called ”Fishpond” started beeping indicating there was an aircraft beneath us. Then all hell broke loose! Photo 6 – The author May 1945 My instrument panel exploded, obviously hit by a shell, and I was hit on the forehead by metal which stunned me. Then I realised that everything was very bright and the port wing outside my workstation was on fire. I rolled onto my back as I had done many times diving from the edge of swimming pools and then counted five before pulling the Rip Cord. I felt the opening shock of the chute between my legs and I looked up. I was horrified! I thought the silk canopy had come off because seemed so small! Then I realised it was about 30 feet above my head on long risers! This reminded me of the time I was collecting my parachute and the chap in front of me asked the little blond WAAF handing them out. ”Do these chutes ever failed to open?” She coyly replied, ”We’ve never had any complaints, Sir!” I pulled the riser, the chute responded and I felt better! It was all so comfortably quiet after the noise and confusion in the Lancaster. I WAS ALIVE! I floated down gently and I could see two parachutes of other crew members below me and I could see the ground was covered in snow before I became completely enveloped in thick cloud. Then my parachute wrapped itself round a clock tower and I crashed into it, knocking myself out with a sharp blow to my head! I don’t know how long I was unconscious but when I came to I could hear rumblings and clickings. I thought I must be lying against a clock face because of these sounds. Then I heard a voice below me calling out and saw a man with a yellow helmet shining a light up at me. I lapsed into unconsciousness again. I have no idea how long I was up there or how they got me down or how I was transported to a medical centre somewhere in Berlin. I regained consciousness to find my skipper, Ralph Allen, bending over me and a German doctor stitching my head. Ralph had parachuted into a tree in someone’s garden. Next, we were taken to a hospital where all five of us who had escaped from our Lancaster were in the same room, being looked after by two British Army medical orderlies who had been captured in France in 1940. Sadly our two gunners didn’t make it. While we were in the hospital, it was discovered my right arm and right leg were broken so they were put in plaster. We were under guard throughout the two days we were in hospital and also when we were taken by train to Dulag Luft in Frankfurt am Rhein, the collection centre for shot down Allied aircrew. Here we were segregated into officers and NCOs, so Ralph and I never saw our other three crew members again. We were put into solitary confinement in unheated cells which was pretty miserable with two still damp plasters. We were interrogated and photographed (Photo 6) and given a Red Cross postcard to send to our next of kin to let them know we were alive. The cards took about five weeks to reach them. Early in January 1944, we were put into a closed cattle truck marked in French JASAM Vol 6 No 1, December 2011 | 31 How to earn a golden caterpillar ”8 horses/40 men” with 46 other prisoners of war. Our journey took two days with many stops until we finally arrived at Sagan in Silesia, where we were driven to Belaria where a brand new extension of the Stalag Luft III POW camp had been built. The German guards took us into the camp which was covered in a few inches of snow, they shut and locked the gates behind us and said, ”For you, the war is over!” I was now a Kriegsgefangener! One of the first people to greet us was the camp doctor, British Army Captain Norman Monteuuis, who had been a prisoner of war since 1940. He saw me hobbling through the snow with my bandaged head and plastered arm and leg and said ”Ah! My first patient! Come with me to the sick quarters”. So I started prison life having my head wound treated and the plasters removed from my arm and leg. I was young, only 21, and made a total recovery except i have never been able to straighten my right arm which doesn’t matter because I am left handed. I made application to become a member of the Caterpillar Club while I was in Stalag Luft III and eventually received my little golden caterpillar with red eyes of course. Photo 9 – Golden caterpillar pin Stalag Luft III grew from the initial handful of us to over 1000 men and our lives were disciplined but made bearable with Red Cross parcels of food supplementing the German rations. The Red Cross also provided boots, musical instruments and sporting equipment. But in January 1945 our rather orderly life style ended when we were marched out into the snow at 4.30 one morning and given one Red Cross parcel for every two men. This was the beginning of an 80 kilometre trek to get us to another prison camp away from the advancing Russians. But that is another story. Photo 8 – G for George at Australian War Memorial 2001 32 | JASAM Vol 6 No 1, December 2011 Air Vice Marshal Eric Stephenson AO OBE JASAM Vol 6 No 1, December 2011 | 33 Annual Scientific Meeting Canberra 2010 34 | JASAM Vol 6 No 1, December 2011 JASAM Vol 6 No 1, December 2011 | 35 Annual Scientific Meeting Canberra 2010 36 | JASAM Vol 6 No 1, December 2011 JASAM Vol 6 No 1, December 2011 | 37 Annual Scientific Meeting Newcastle 2011 38 | JASAM Vol 6 No 1, December 2011 JASAM Vol 6 No 1, December 2011 | 39 Annual Scientific Meeting Newcastle 2011 40 | JASAM Vol 6 No 1, December 2011 JASAM Vol 6 No 1, December 2011 | 41 Honorary members & ASAM Committee Honorary Members The ASAM Committee Year awarded Dr Jeff Brock 2011 President Dr Greig Chaffey 0437 496 002 [email protected] Mrs Jan Chaffey 2010 Dr Greig Chaffey 2010 Dr J B Craig (Foundation Member) 2008 Dr B Costello (Foundation Member) 2008 Dr Graeme Dennerstein 2007 Dr Malcolm Hoare RFD 2007 Dr Michael Lischak 2003 Treasurer Capt Glenn Todhunter 2003 Dr Richard Williams (Chief Medical Officer NASA) 2003 Dr Jeanette TB Linn OAM 2002 Dr Andrew Marsden 0419 965 115 [email protected] Vice-President Dr Barney Cresswell 0403 584 770 [email protected] Air Vice Marshal Glen W (Bill) Reed 2001 Secretary Air Vice Marshal Eric Stephenson AO, OBE, QHP 1999 Dr John Colvin OAM 1999 Dr Len Thompson 1999 Dr Heather Parker 0418 715 340 [email protected] Dr Eric Donaldson OAM 1999 Public Officer Dr Bert Bailey 1999 Dr Ron Wambeck DFC 1999 Dr Dorothy Herbert OAM 1997 Dr Craig Schramm 0418 239 190 [email protected] Dr Derek Dawes 1997 Immediate Past President Dr AW Erenstrom 1987 Mr Doug Patterson 1981 Air Vice Marshal LK (Kiwi) Corbet 1979 Dr Warren Harrex 0409 466 632 [email protected] Dr JC Lane OAM 1979 Committee Dr HJ Mail 1978 Dr FS Parle OBE 1975 Air Vice Marshal EA Daley CBE, KHP, QHP 1961 Dr Gordon Cable 0412 658 240 [email protected] Dr (non-medical) JH Martin, Director of Physics at the Melbourne Cancer Institute 1956 Dr Ian Cheng 0419 207 111 [email protected] Dr David Emonson 0419 145 983 [email protected] Dr Tracy Smart 0458 737 693 [email protected] Dr Adrian Smith 0413 940 694 [email protected] 42 | JASAM Vol 6 No 1, December 2011 2011 Membership List AUSTRALIAN CAPITAL TERRITORY Coote, Dorothy Doherty, Belinda Ferguson, Alan Fitzgerald, David Gordon, Andrew Harrex, Eleanor Harrex, Warren Henry, Hayden Howe, John Jolly, Danielle Joseph, Vince Kennealy, Steven Klar, Danielle Lee, Doug Lee, Rob McGinniss, Elicia Moller, Graeme Muthalaly, Rana Norgrove, John Pitcher, Andrew Roantree, Dennis Ross, James Schramm, Craig Seah, Mike Sham, Tak Smart, Tracy Smiles, John Stephenson AO OBE, Eric Travers, Tamsin Van Der Rijt, Carmel Wilkins MBE, Peter Williams, Felicity NEW SOUTH WALES Lawson, Peter Abraham, George Adler, Paul Affleck, John Agarwal, Manjul Allan, Roger Alterator, Rick Ambrose, Grahame Arber, Philip Arnaudon, Peter Austin AM, Tony Bailey, Yvonne Baker, Eric Ban, Arthur Bayliss, Geoff Bennett, Tom Beran, Roy Berry AM, Andrew Betts, Keith Bhatt, Priti Blainey, Chris Bridger, Diane Brown, Russell Brown, Margaret Bruck, Catherine Caswell, Gabi Chara, Asthika Cheng, Ian Cheung, Leanne Coceancig, Paul Collie, Trish Cooke, David David, Timothy Davies, Gordon Davis, Jennie Davis, Peter Day, Shane Delaney, Darren Den, Barry Duffy, Peter Duffy, Vincent Duflou, Johan Durkin, Dean Eastman, Creswell Edwards, Charlie Elder, John Evans, John Fenn, Chris Fernando, Shiran Ferris, Joe Field, Catherine Fitzgerald, Guy Flanagan, Izaac Foong, Jennifer Forssman, Bradley Foster, Paul Frumar, Kim Game, Justin Gardner, Trevor Garne, David Garrard, Laurie Gibson, Margaret Givney, Jane Hall, Pedita Hartley, Richard Harvey-Sutton, Phillipa Hazell, Luke Hazelton, Ken Henderson, Cameron Heyning, Marc Higgins, Graham Hill, Dolores Hill, Michael Hopwood, Christopher Horgan OAM, Terry Horowitz, Greg Howle, Stephen Hughes, Paul Hughes, Whitney Hutchins, Ian Jackman, Kim Jacobs, Mark Jambor, Christopher Jander, Caron Johnston, Colin Jongbloed, Larry Keller, Andrew Kelly, Bernard Keys, Phil Khan, Ijaz Khan, Jennifer Khan, Azhar Khoo, Nee Chen Kontkanen, Sanna Kroll, Barry Kwon, Neville Lee, Janet Lehmann, Wayne Lele, Vinoo Leppard, Steve Lewin, Rob Lewin, Robert Liebenberg, Albert Lilienthal, Craig Lim, Hardy Livingstone, Elizabeth Lose, John Lurie, Eddie Lye, Philip MacDonald, Colin Maclarn, Graeme Magee, Marion Mahmood, Javed Manderson, Kate Manku, Mehm Manners, Vincent Martin, Peter Massie, Colin Mathews, David Maus, Lisa May, Simon McGilvray, Steven McGinty, Mary McInerney, Peter Meades, Robyn Micallef, Robert Milliken, Andrew Mills, Ross Moore, David Moroney, Kerry Morrison, Ion Myers, Phillip Nerwich, Neil Ng, David O’Brien, Peter Oh, Evan Ohana, Joseph O’Kane, Gabrielle Oswald, Karen Oxbrow, Doug Parikh, Jitendra Parrish, Roger Pascoe, Glenn Peterson, Mark Phillips, David Phonesouk, Somnuk Pinkstone, Jeffrey Pittar, Graham Porges, Stuart Price, Eddie Purches, Peter Randhawa, Jey Rankin, Tim Rao OAM, Balaji Reppas, Napoleon Richardson, Brian Richardson, Natasha Robertson, Rob Roby, Howard Rockman, David Rowe, George Ryan, Mark Saareste, Ain Sachdev, Darshan Sagar, Puru Saunders, Alan Simpson, Garry Sinclair, Murray Singleman, Glenn Sloane, Rod Smith, Justin Smith, Richard Stephenson OAM, Jeff Stern, Harry Stringfellow, Gavin Summers, Frank Tang, Derek Tang, Kong Chan Taylor, Christopher Taylor, Giles Thatcher, Lewis Thomas, Geoff Thomas, Michael Thomas, Vin Thomson, Clyde Thorogood, Paul Tinning, Dick Tongson, Steven Tonkin, Alexander van der Walt, Annemarie Viljoen, Deon Webber, Chris Westphalen, Neil Wheeldon, Lorraine Wicks, Leon Williams, Bruce Wingate, Richard Wright, Dean Wulff, Neville Zdenkowski, Andrew Cronin, Sheilagh Cunningham, Greg Daniels, Marc Davies, Ian NORTHERN TERRITORY Dawbarn, Tim Dietz, Walter Brotherton, Michael Donaldson OAM, Eric Brummitt, David Dowd, Peter Dimond, Greg Dunn, Tom Fuller, Margaret Dunne, Elaine Giese, Richard Easton, David Hardcastle, Doug Edwards, Norm Loh, Lawrence Evans, John MacDonald, Andrew Fenner, Peter Mahasuria, Asha Fukuzawa, Hiroyoshi Mahendrarajah, Gardner, Amanda Tharmalingam Gilford, Chris McCullough, Jamie Goldston, John Pettigrew, Bill Griffin, Jim Pettigrew, Jill Hampson, Greg Rubin, Colin Harding, Philip Scott, Hamish Hardy, Tim Stacey, Mike Hashim, Rozi Thompson, Geoffrey Hawes, David QUEENSLAND Hay, Rosemary Abrahams, Jim Herat, Bandu Adsett, Geoffrey Hetherington, Ross Ahmed, Waseem Hickey, Michael Ambler, John Hill, Adrian Andrews, Christopher Ho, Lee Angel, Paul Hodge, Jon Apel, Andrew Holborn, Luke Beeston, Peter Holt, Geoff Bennett, Ann Horsburgh, Scott Birchley, Simon Horwood, Michael Black, Dan Hosegood, Ian Bondeson, Kimberley House, Diana Bowley, Don Housego, Ian Bradley, David Howes, Andi Brock, Jeff Hudson, John Bromet, Michael Jack, Carolyn Bryant, Andrew Jenkins, Tony Byrnes, Patrick Jennings, Scott Cameron, John Joice, Paul Campbell, Jessica Joseph, Deep Carr, Martin Kearney, John Castrisos, Edwin Kearney, Stephen Chaffey, Greig Keating, Michael Chaffey, Jan Kelly, Simon Chambers, Aaron Kennedy, Robert Chater, Alan Keyes, Richard Clem, Peter Kitchener, Scott Clements, Michael Kleinig, Daniel Collyer, Bill Koppen, Blair Cormack, Ian Lahanas, John Costigan, Dennis Lamb, John Cotter, Margaret Lanham, Paul Lawson, Stephen Cranstoun, Peter JASAM Vol 6 No 1, December 2011 | 43 2011 Membership List Leggat, Peter Lillicrap, Gary Litherland, Gary Little, Simon Marendy, Peter Marks, Warwick Marshall, Ian Marshall, Jodie Maxwell, Ian McAdam, Margaret McCaldin, Charles McCombe, Don McCoy, Jodie McDonnell, Michael McPhee, Ewen Moon, Maria Munn, Josh Naidoo, Pat Nicholson, Geoff Novakovic OAM, Petar Oltvolgyi, Csongor O’Malley-Ford, Judith O’Toole, Robin Palmer, Kym Parker OAM, Heather Pascoe, Geoff Peel AM CSC, Graeme Perera, Shawn Pietzsch, Tom Potter, Thomas Powell, Ben Read, Michael Reader, Stuart Reed, Bill Rivlin, Ian Rosewarne, Phil Rubis, Carl Ruscoe, Peter Seckler, Wolfgang Seliga, Stan Sharma, Anita Sharma, Anil Shumack, Paul Smith, Shane Spall, Andrew Spicer, Paul Steel, Sue Stone, John Sutch, Allan Swanson, Craig Talbot, William Taylor, Dean Taylor, Ross Thomas, Bob Thomas, Dale Thompson, Richard Todhunter, Glenn Tong, Douglas Turner, John Ullman, Geoff Valentine, Matthew Vogel, Willem Walker, Nathan Whitworth, Andrew Wilson, Chester Windley, Stephen Wong, Max Woodward, Jane Yantsch, Phil Yoke Choon Lip, Patrick Zischke, Kevin SOUTH AUSTRALIA Alcorn, Bruce Ameerjan, Feroz Anderson, Daniel Babu, Suresh Baczyk, Iwona Barker, Brent Barker, Tony Bebb, Edward Bloom, Martin Bryant, Geoff Bulyga, George Burrough, Timothy Cable, Gordon Capps AM RFD, Roger Chadha, V Charlton, Peter Corbett, Mark Crompton, John Davies, Glyn De Sari, Adrian Del Fante, Peter Fernando, Colin Flabouris, Arthas Fleming, Graham Forrester, Jackie Graham, Geoff Griggs AM, Bill Heah, Richard Hume, Clive Jennings, Reece Jolly, Richard Kasauskas, Jonas Kokar, George Lewis, Scott Librarian, The Linn OAM, Jeanette Martin, Stewart Menzies, Geoff Miller, Alan Murray, Neil Nelson-Marshall, Rae Oo, Htun Htun Oppermann, Brett 44 | JASAM Vol 6 No 1, December 2011 Page, Nicholas Partridge, Ian Pike, Lincoln Ramsey, David Schultz, Barry Shivashankaraiah, Anupama Singh, Bhupinder Smith, Adrian Storey, Adam Thompson, Bryan Thorpe, Peter Trappitt, Andrew Tucker, Richard Waite, Chris Ward, Kym Watson, Christopher Wilson, Richard Wood, Tim TASMANIA Ayton, Jeff Dow, Doug Emmett, Ian Farmer, John Graham, Stewart McCartney, Paul Plumley, Noel Roddick, Ian Rowan, Pauline Skinner, Marcus Tooth, Michael Treplin, Michael Tymms, Anthony Walker, Bob VICTORIA Abou-Seif, Nader Allen, Robert Alpins, Noel Amini, Alex Anderson, Malcolm Andrade, Simon Antonenko, Peter Aouad, Ayman Atkinson, Peter Baddeley, Ken Balnionis, Andrius Barry, Jim Bassovitch, Oleg Baynes, Michael Bernstein, Allan Birman, Sam Black, Rhyll Bloom, Philip Boltin, Phillip Boothby, Graham Brook, Wilfrid Buttery, Robert Cameron, Don Cartwright, Paul Cato AM, Alex Chesney, Christopher Cheung, Philip Chew, Denis Christiansen, Rowena Clift, Andrew Connor, Michael Cooper, Max Costello, Brian Daniell, Mark Davis, Ivor Day, Geoff De Clifford, Max De Sousa, Tony Demediuk, Nicholas Dennerstein, Graeme Devincentis, Fio Dickman, John Ding, Yock Seck Douglas, Ian Duncan, Colin Dwyer, Bill Dyson-Berry, John Ellis, Greg El-Sheikh, Khaled Emonson, David Farmer, Ian Farrow, Jeff Fawcett, Rodney Ferguson, Malcolm Fifield, Scott Forster, Mike Fuller OAM, John Galtieri, Vince Gardiner, Scott Gaze, Doug Gee, Murray Gibson OAM, Tony Gill, Cecil Grace, Carl Green, Catherine Gunn, Barry Habersberger, Peter Hamer, Angas Handley, Paul Haralambakis, George Harris, Andrew Harris, Phil Hauptman, Oded Hince, Monica Hirschfield, Marcus Hoare, Julian Hoffman, Tamaris Holian, Annette Homewood, Michael Homolka, Sue Hooke, David Hunt, Campbell Irvine, Gerald Jackson, Neil Jelbart, Stephen Johnston, Roger Kefford, Marina Kemp, Warren Keppel, Peter Koniuszko, Miriam Kudelka, Peter Kunjidapaadhum, Ganes Lau, Sonny Lazarus, Mark Lazell, Robert Lee, Rodney Leow, Priscilla Lia, David Ling, Andrew Loeffler, Mark Lucca, Luigi Lunz, Richard Macaulay, Geoff MacDonald, Ileene Mack, Heather Mackey, Noel Manolopoulos, John Martiniello, John Marty, David Mazzetti, Julian McCarthy, Anthony McDonald, Colin McInnes, Ian McKenzie, Doug McKenzie, Matt McKnight, David McLean, John McLeod, Liz McMahon, Hal McMahon, Phyllis Merrett, Andrew Miller, Graham Milne, Peter Moffitt OAM, Rob Monash, David Narendranathan, Ramanathan Neath, Adrian Newman, David Ng, Weng Toon Nicolettou, Nick North, Rob O’Brien, Karen O’Day, Justin O’Gorman, Michael O’Kane, Chris Olesen, James Osman, Stan Overton, Mark Pahuja, Om Pape, Arthur Papworth, Gregory Parkes, John Paterson, Ian Pattison, Matthew Peters, Andrew Phan, David Pillai, B Price, Ian Priest, Christopher Reed, Melissa Reid, Ruth Renehan, Mark Reynolds, Kath Robertson, Shelley Roth, Norman Sabetghadam, Reza Samuel, Manojkumar Sandor, Les Schneeweiss, Anthony Searle, Russell Serong, Roger Shannon, Meg Sharma, Rajeev Sheppard, Colin Shields, Richard Shute, Simon Silver, John Smith, Michael Stapleton, Ian Stewart, Tony Sullivan, Laurence Tomkins, Ron Toogood, Geoff Tran, Duc Nguc Truesdale, Melinda Tunbridge OAM, Raoul Van Der Spek, Tony Vandenberg, Rosemary Vingrys, Algis Walters, Barry Ward, Richard Ward, Salena Warren, John Watson, Laurance Webster, Philip Weinrich, John Westerman, Rod Wolf, Peter Wolfe, Rick Wong, William Workman, David Worsnop, David WESTERN AUSTRALIA Adamson, Stuart Adeoye, Adegbuyi Afolabi, Olajumoke Al Qubaisy, Omar Andrews, Reg Aniyi, James Arthur, Stephen Barr, Tony Bateman, John Benson, Michael Briggs, Patrick Cadden, Frances Catanchin, Andrei Chandran, Mohan Christensen, Bernard Collings, Brian Collis, David Craig, John Cresswell, Bernard Daniels, Dru Davies, John Denz, Chris Dobson, Ron Dorkham, Zaki Dymond, Jane Foote, Andy Forgione, Nicholas Gorman, Paul Hartill, Graeme Harvey, Ross Harwood, Abigail Henwood, Anthea Hernaman, Peter Heyworth, Peter Hoare, Malcolm Hochberg, Anthony Hodge, Matthew Hodgkinson, Airell Holt, David Hutchinson, Allan Inoue, Yoshi Junckerstorff, Reimar Keating, Darren Khong, Chee-Hoong Kotai, Frank Laney, John Langford, Stephen Lee, Colin Liddell, Rob Marsack, Christine Marsden, Andrew Martin, Phillip McConnell, Christine Mears, Mike Mikhaiel, Nazmi Miller, John Milligan, Cathryn Morison, Kent Noble, Phillip Perry, Chris Pleass, Trevor Ravet, Jan Robson, Jenny Rose, Chris Ryan, Elizabeth Rynn, Chris Sim, June Singh, Harpreet Sovann, Ritthy Starling, Doug Stewart, Andrew Stott, Barb Stynes, Paschal Swemmer, Ebbie Talbot, Jane Tan, Hui Thelander, Charles Thompson, Larry Van Ballegooyen, Andrew van Reenen, Charles Ward, Olga Wee, Alvin Hock Peng White, Craig Wilson, Glenda Wong, Yim-Kong Woods, Tom Zentner, Adrian OVERSEAS MEMBERS CANADA Sardana, Tarek Denmark Lyduch, Steffen FIJI Biumaitotoya, Isireli Goundan, Ravinesh Hong Kong Fu, Samuel Lau, Hay Tung Lee, Horace Yan Wang Liew, Michele Ong, Rose O’Tremba, Frank Pei, Benjamin Searl, Robyn Iran Ronaghi, Iman Malaysia Kwong, Khiew Siaw New Zealand Baldwin, Dave Blackmore, Robert Thompson, Len Visser, Robert Papua New Guinea Chelvanathan, Athithan Kalana, Charles Mackerell, John Taunao-Lega, Heni Singapore Joang, Kim Soo Wong, Raymond Sri Lanka Herat-Gunaratne, Nimal Thailand Banasarnprasit, Sethanai Muangsillapasart, Viroj Premmanisakul, Sumait United Arab Emirates Chalkley, John Chang, Rae-Wen Lee, Robin Luna, Eleanor United Kingdom Morgan, Dewi Smith, Thomas United States of America Contiguglia, Joseph Lischak, Michael Williams, Richard JASAM Vol 6 No 1, December 2011 | 45 Information for authors Journal of the Australasian Society of Aerospace Medicine Information for Authors JASAM is published annually and contributions are welcome at any time. JASAM welcomes contributions including letters to the Editor on any aspect of aersopace medicine. Manuscripts must be offered exclusively to JASAM unless the manuscript is accompanied by a copyright exemption. All manuscripts and contributions are subject to peer review and to editing. Contributions are preferred by e-mail to: [email protected] Typewritten contributions should be sent to: The Editor JASAM Australasian Society of Aerospace Medicine PO Box 4022 BALWYN VIC 3103 Requirements for Manuscripts JASAM follows the agreed conventions for medical journals. Full details of the requirements for manuscript preparation are available on the internet at the site http://www.icmje.org An electronic copy (on disc or sent by e-mail) should be submitted. The copy should be able to be read in MS Word and formatted to A4 paper, using Arial or Times New Roman 10 font. Reviewers will be provided with a copy with the authors’ names, affiliations and acknowledgements removed. The title page should contain the title, list the names and qualifications of all authors as well as the position and institutional address at the time of submission. One author should be identified as the correspondent along with his or her postal address, telephone number and email address. An abstract of no more than 250 words should be included with headings for Aim, Methods, Results and Conclusion. Abbreviations should be avoided and if used only after they have appeared in brackets after the completed expression – eg, Journal of the Australasian Society of Aerospace Medicine (JASAM). SI units should be used but altitude may be expressed in feet. Figures and Tables are encouraged and should be entered on separate pages and numbered sequentially underneath eg Figure 1 or Table 1 with an appropriate self-explanatory legend. Their preferred location should be indicated in the manuscript. References should be presented in the “Vancouver” style. References should be numbered consecutively as they appear in the text as superscript numbers (eg, text1,2). An example of the format for journals and books is given below: 1. Cable GG, MacFarlane A. Is neurological hypobaric decompression illness a more common phenomenon than we think? J Aust Soc Aerospace Med 2006; 2(2):3-11. 2. H eath D, Williams DR. Man at high altitude, 2nd ed. Edinburgh: Churchill Livingstone, 1981: 56-65 Permission to reprint articles will be granted by the Editor, subject to the author’s agreement, provided that an acknowledgement giving the original date of publication in JASAM is printed with the article. Reviewers All articles will be subject to blind review by at least two reviewers. Members with expertise who are willing to join the panel to review articles for publication are invited to contact the Editor. Editor: Editor Dr Warren Harrex Dr Adrian Smith has been appointed editor from January 2012 Email: [email protected] Editorial Assistant for inquiries/and submissions: Anne Fleming Tel: 03 9899 1686 Email: [email protected] 46 | JASAM Vol 6 No 1, December 2011 JASAM Vol 6 No 1, December 2011 | 47 48 | JASAM Vol 6 No 1, December 2011