Progress of the German working group for the cleaning of DaVinci
Transcription
Progress of the German working group for the cleaning of DaVinci
Progress of the German working group for the cleaning of DaVinci-instruments Dr. Markus Wehrl wfk – Cleaning Technology Institute e.V. CSC Anual Scientific Meeting / April 14th 2015 / Chepstow DaVinci®-System Dual Blade Retractor Black Diamond Micro Forceps Large Clip Applier DaVinci® FDA clearance in 2000 DaVinci S® DaVinci Si® DaVinci Xi® introduced in summer 2014 Tenaculum Forceps ProGraspTM Forceps HotShears TM Mega SutureCutTM Needle Driver Dissecting forceps EndoWrist Stabilizer Operated Robotic Systems Europe Canada 22 416 Direct Germany 61 France 60 Belgium 30 UK 29 Switzerland 20 Netherlands 17 Sweden 15 USA 1,878 Brazil 7 Argentina 4 Chile 4 Venezuela 3 Mexico 3 Colombia 2 Panama 1 Uruguay 1 Latin America 25 Saudi Arabia 11 Israel 6 Qatar 4 Pakistan 2 Egypt 1 Kuwait 1 Lebanon 1 Middle East 26 Distribution Italy 65 Spain 25 Turkey 16 Russia 14 Denmark 13 Norway 10 Czech Republic 8 Finland 5 Austria 4 Ireland 3 Greece 8 Romania 6 Bulgaria 1 Slovakia 1 Poland 1 Portugal 1 Slovenia 1 Cyprus 1 Monaco 1 Asia 191 Japan 80 South Korea 36 China 22 India 21 Taiwan 14 Thailand 7 Singapore 5 Malaysia 4 Indonesia 1 Philippines 1 72 systems in 70 hospitals (Feb. 2014) Australia 27 Robotic Instruments Housing Distal Working End Shaft Maryland Bipolar Forceps 8 mm, 10 reproc. cycles Shaft diameter: 5 or 8 mm 8 mm instruments are predominantly used Number of reprocessing cycles: 10x to 25x depending on the type Reprocessing in Germany… Once in time (Spring 2011)…. …a hospital sent instruments of unknown status under unknown conditions to a laboratory for analyzing residual proteins….The lab applied immunological (?) and nephelometric (?) methods and found more albumin than total protein….. The lab had some “scientific problems” and the hospital, too. The results were reported to local authorities, these informed federal authorities Reprocessing of robotic instruments was interdicted immediately. Formation of the WG Establishment of group: August 23rd 2012 AIM: Establishment of a method for the reproducible assessment of cleaning efficacy within process validation (PQ). Two Publications Wehrl M., Michels W., 2013 A method for testing the cleaning of MIS robotic instruments. CentralService 2013(3): 202-207 Wehrl M., Albers G., Bühler K., Diedrich D., Frister H., Heintz M., Hubert H., Köhnlein J., Michels W., Rosenberg U., Roth K., Wallace B., 2014 Round robin tests conducted by the working group DaVinci („AG DaVinci“) to establish a method for testing the cleaning of MIS robotic instruments. CentralService 2014(3): 173-179 Two Elution Methods No. of applications/ reprocessing cycles: 0 < maximum No. Type I Non-destructive testing Elution of distal working end and elution of shaft interior No. of applications/ reprocessing cycles: Maximum No. Type II Destructive testing Dismantling of distal working end and elution Dismantling of shaft element and elution Type I-Testing: Non-Destructive The tip is eluted (upright position) using a vial that is filled with 6 ml 1 % SDS-solution (pH=11) Elution time: 30 min, periodic movement of tip (4x) Following this eluate is filled in flush port 1 to elute the interior of the shaft Elution time: 30 min, periodic redrawing and injection of the solution (4x) Picture by Dr. W. Michels Protein quantification: mod. OPA- or BCA-method Pre-Test: Recovery Rate CORRECTED RECOVERY RATE [%] 100 Maryland Bipolar Forceps soiling into the shaft element 100 µg, 250 µg, 500 µg and 1000 µg BSA n=3 instruments n=8 unsoiled control instruments OPA 90 80 70 60 50 40 30 20 10 0 100 250 500 1000 AMOUNT OF SOILING (BSA) [µg] Recovery Rates of the four experimental sets: 69.1 – 79.3 % (corrected for false-positive) Soiling of the Shaft: „Muzzle Loader“ • PTFE-capillary (inner diameter: 0.6mm) filled with approx. 2 µl blood • Picture analysis: determination of the volume of loaded soil (capillary previously calibrated) • Injection of soil • Residues in the capillary eluted and quantified using the OPA-method Recovery Rate [%] Round-Robin on Type I-Testing 160 OPA 140 BCA 120 BCA-SQ Maryland Bipolar Forceps reactivated sheep blood ~2 µl into the shaft ~2µl onto the tip n=3 instruments per lab OPA / BCA 100 80 60 40 20 0 A B C D E F Lab Mean Recovery Rate: 95.5 ± 20.5 % (not corrected for false-positives) Type II-Testing: Destructive The cap of the housing is dismounted, the bowden cables are cut and the tip is dismantled. Bowden cables and electric cables are cut at the crimping site on the hypotube. The distal working end is eluted in a vial with 3 ml 1 % SDS (pH=11) Elution: 30 min, periodically vortexed (4x) The ends of the shaft (containing the Bowden cables) are closed, 4 ml 1 % SDS (pH=11) are injected Elution: 30 min, periodically vortexed (4x) Protein quantification: mod. OPA- or BCA-method Recovery Rate [%] Round-Robin on Type II-Testing DW-OPA 160 140 120 100 80 60 40 20 0 SE-OPA DW-BCA SE-BCA A B C D E F Lab It was unsure, where the 2 x 2 µl of blood had been deposited in the shaft. At the silicone gasket or at parts that were analysed with the shaft element? G Maryland Bipolar Forceps Reactivated sheep blood 2µl onto the tip 2 µl into the shaft at the silicone gasket 2 µl into the shaft approx. 15 cm above the distal working part n=3 instruments per lab Round-Robin on Type II-Testing Recovery Rate [%] Residues of tip and shaft element were added 160 140 120 100 80 60 40 20 0 OPA BCA A B C D E F G Lab Mean Recovery Rate: 83.1 ± 16.6 % (not corrected for false-positives) Analysis of Eluates Prerequisite: Eluates must not be turbid. If turbid rejected Suitable methods for protein quantification: • Modified ortho-Phthaldialdehyd (OPA)-method (EN ISO 15883-1) • Bicinchoninic acid (BCA)-method (EN ISO 15883-1) • e.g. INTERCHIM BC Assay Protein Quantification Kit • e.g. QuantiPro BCA Assay Kit • e.g. Miele-test kit using the reflectometer Rqflex plus 10 Reflectoquant (Merck, Germany) Interfering Substances • OPA and BCA exhibit an interference with substances released from the instruments • New instruments reprocessed 5x exhibited a false-positive protein content of 48.8 ± 5.60 µg • After >20 reprocessing cycles interfering substances were present to strongly varying amounts (5 – 50 µg) • Interfering substances could not be identified. One strongly interfering component is tungsten from the bowden cables • Extraction of interfering substances using chloroform, cyclic hexane, ethyl acetate, xylol failed • Protein cleaning columns failed, they gave a protein loss of approx. 50 % but no removal of interfering substances Interfering Substances • Corrosive (H2O2) or highly alkaline reprocessing chemicals are suspected to increase the problem of interfering substances NO SYSTEMATIC ERROR NO CORRECTION POSSIBLE Assumption made in the group: Protein quantification is NOT corrected for false-positive interference. It is assumed that false-positive interference and the recovery rate below 100 % are compensating each other partially. Acceptance Criteria • All outer surfaces of the instruments must be visually clean • The residual protein content is judged on the basis of the “surface-related protein-content”: 3 µg/cm2 • ISO TC 198 WG13: discussing 2 – 6.4 µg/cm2 • 3 µg/cm2 applied by the German guideline for the validation of manual reprocessing procedures (DGKH, DGSV, AKI and VAH), October 2013 • 3 µg/cm2 applied by the German guideline for the validation of automated reprocessing procedures for thermo-stabile instruments (DGKH, DGSV, AKI), revised October 2013 Surface Only relevant surfaces (patient contact, soiled) are considered Maryland Bipolar Forceps, MBF, Intuitive Surgical Inc., USA Area Distal Working Part: inner and outer surfaces of metal part, including 2 cm bowden cables/cables 27 cm2 Shaft Inner Surface: Length 42.5 cm, including cables, hypotubes, flush tube 266 cm2 Relevant part of Shaft Element: 6 cm of distal part of shaft, including Bowden cables/cables, 1.5 cm of flush tube 24 cm2 Acceptance Criteria Using the 3 µg/cm2 acceptance value • Type I-Testing: 155 µg • Type II-Testing: - Distal Working Part: 80 µg - Inner of Shaft Element: 75 µg The proposed maximum values were not well received by federal authorities like BfArM, as the Guideline of the RobertKoch-Institute (RKI) postulates a maximum of 100 µg/instrument. Conclusion Standardized and specified methods were established. Recovery rates and reproducibility were shown to be fair and acceptable with regard to the complexity of the instruments. The method is accepted by federal authorities like BfArM (Federal institute for pharmaceuticals and medical devices, Bonn) Federal authorities recognized that interfering substances might influence residual protein quantification but do not pose a hazard to patient safety as supported by data from different cytotoxicity studies. Conclusion Residues in the housing are no problem with regard to patient safety Colored areas in the housing resulted from wear of friction, corrosion and precipitates from water and are not critical with regard to hygiene It was recognized by BfArM, that DaVinci instruments can be reprocessed in general Hospitals that had experienced interdiction of reprocessing DaVinciinstruments are back to normal reprocessing operation. Outlook The working group currently sets up a “field-investigation”: 5-10 hospitals are invited to apply the methods and to share results. Aim is to obtain a pool of results from at least 100 tested instruments Alternative methods for the rapid assessment of cleanliness will be tested and compared Results will give information about: - the applicability of the methods in hospitals - average values for residual protein content Results of the “field-test” will be published If you are interested in….. …..reprocessing of complex medical devices and beyond…. …..actual developments in cleaning, disinfection, sterilization…. …..guidelines, working groups and beyond…… then join us at: “Colloquium Medical Instruments” May 21st 2015 Hilton Conference Center Düsseldorf (conference language DE/EN) www.wfk.de Thank you very much….. ….for your interest and attention Dr. Markus Wehrl wfk – Cleaning Technology Institute e.V. Campus Fichtenhain 11 47807 Krefeld Germany ++49-2151-8210-170 [email protected] About the speaker • Born 1974 • 1995-2001 Studies in biology and PhD at the Research Center for Infectious Diseases of the University Würzburg, Germany • Since 2006 with wfk, since 2011 head of the Dept. of Hygiene and Microbiology • Focus: - thermo-labile MD/implants - low-temp sterilization procedures - supercritical CO2 processes • Activities: - coordinator for DGKH e.V. of the guideline on thermo-labile endoscope reprocessing - WG “Performance testing of instrument cleaners” of DGKH e.V. - WG „AG DaVinci“ on robotic instruments - ISO/TC94/SC13/WG6 on surgical textiles The speaker-private Hobbies: - Amateur Radio at frequencies above 50 GHz - Growing of carnivorous plants (Drosera sp.)