Fluid, Electrolytes, and Acid

Fluid, Electrolytes,
and Acid-Base Therapy
Case
A 50-year-old 50 kg. man was diagnosed with duodenal
cancer with gastric outlet obstruction.
T 37.1c, P 88/min, R 18/min, BP 100/60 mmHg. He
appeared moderately dehydrate.
NG tube insertion revealed large amount of old food
particle in his stomach. Urine specific gravity was 1.030.
His laboratory results were Na+ 120 mEq/l, K+ 3.0 mEq/l, Cl95 mEq/l, HCO3- 29 mEq/l.
How should we prepare this patient for an operation?
Topic
1) Content and composition of GI tract secretion
2) Sodium abnormalities : diagnosis and
management
3) Potassium abnormalities : diagnosis and
management
4) Impact of electrolyte abnormalities on organ
systems
Topic
1) Content and composition of GI tract secretion
2) Sodium abnormalities : diagnosis and
management
3) Potassium abnormalities : diagnosis and
management
4) Impact of electrolyte abnormalities on organ
systems
Content and composition of
GI tract secretion
ECF volume deficit is the most common fluid disorder in
surgical patients
The most common cause of volume deficit in surgical
patients is loss of GI fluids
Vomiting
Nasogastric suction
Enterocutaneous fistula
Diarrhea
Composition of GI secretions
Type
Volume
(mL/24h)
Na
(mEq/L)
K
(mEq/L)
Cl
(mEq/L)
HCO3
(mEq/L)
Stomach
1000-2000
60-90
10-30
100-130
0
Small
intestine
2000-3000 120-140
5-10
90-120
30-40
Colon
vary
60
30
40
0
Pancreas
600-800
135-145
5-10
70-90
95-115
Bile
300-800
135-145
5-10
90-115
30-40
IV fluid choices
IV Fluid
Dextrose
(g)
Na
(mEq/L)
K
(mEq/L)
Cl
(mEq/L)
Others
(mEq/L)
Osmolarity
(mOsm/L)
NSS
-
154
-
154
-
308
109.4
Lactate
27.7
272.7
RLS
-
130.4
4
Acetar
-
130
4
108.7
5%D W
50
-
-
-
Acetate
28
-
5%D N/2
50
77
-
77
-
273.4
252
406
GI secretions & IV Fluids
5%D-N/2 + KCl 20 mEq/L
Na
(mEq/L)
K
(mEq/L)
Cl
(mEq/L)
HCO3
(mEq/L)
60-90
10-30
100-130
0
Type
Volume
(mL/24h)
Stomach
1000-2000
Small
intestine
5%D-N/2
2000-3000
120-140 + KCl
5-1030 mEq/L
90-120
Colon
vary
RLS, Acetar
RLS, Acetar
60
30
RLS,
Acetar
30-40
40
0
Pancreas
600-800
135-145
5-10
70-90
95-115
Bile
300-800
135-145
5-10
90-115
30-40
Topic
1) Content and composition of GI tract secretion
2) Sodium abnormalities : diagnosis and
management
3) Potassium abnormalities : diagnosis and
management
4) Impact of electrolyte abnormalities on organ
systems
Sodium
Principle cation of ECF
Total body Sodium
Reflexes ECF volume
NOT serum Sodium level
Hyponatremia /Hypernatremia = change in ratio
between total body Na and free water
Serum Sodium
Serum sodium =
Total body Na
Free water
Hyponatremia =
Hypernatremia =
Total body Na
Free water
Total body Na
Free water
Volume can be high, normal, low
Hyponatremia
Sodium depletion
Dilution from excess ECF free water
Excess of other solutes relative to free
water
Catagorize by volume status
Hyponatremia
Volume
status
High
-Increase
intake
-Postop
ADH
secretion
-Drugs
(antipsychotic,
TCA, ACEI)
Normal
Hyperglycemia/ma
nnitol
-Increase plasma
lipids/protein
(pseudohypoNa)
Low
Decrease Na
intake
-low Na diet,
tube feeding
Increase Na
loss
-SIADH
GI loss
-Water intoxication
(TUR syndrome)
-Vomiting,
NG suction,
diarrhea
-Diuretics
Renal loss
-Diuretics
-Primary renal
disease
-Cerebral salt
wasting
Hyponatremia
Symptoms & Signs
Serum Na control ECF osmolarity and effect intracellular
water cell edema
CNS : headache, confusion, hyperreflexia/hyporeflexia,
seizure, coma, increased ICP
Musculoskeletal : weakness, fatigue, muscle cramps
GI : anorexia, nausea, vomiting, watery diarrhea
Cardio : hypertension, bradycardia (if increase ICP)
Tissue : lacrimation, salivation
Renal : oliguria
Hyponatremia
Treatment
Stop & correct causes
High, normal ECF vol restrict free water
Low ECF Vol IV isotonic saline
Not exceeding 0.25-0.5 mEq/L/hr (6-10 mEq/d)
Too rapid correction in chronic hyponatremia central
pontinemyelinolysis
Severe permanent neurologic disorder
Spastic quadriparesis, pseudobulbar palsy, depressed
consciousness
Calculation
Na deficit = (140 – serum Na) x TBW
2
= (140 – serum Na) x 60 x BW
2
100
Eg. Serum Na 120 mEq/L, BW 50 kg
Na deficit = (140 –120) x 60 x50
= 300 mEq
2
100
Na to be corrected =
(130 –120) x 60 x50
2
100
= 150mEq/d
Hypernatremia
Water loss is most common cause (renal &
non-renal)
Gain Na in excess of water
Can be associate with increase, normal or
decrease ECF volume
Hypernatremia
Volume
status
Ur Na >20 mEq/L
UrOsm> 300 mOsm/L
High
-Iatrogenic Na
administration
-Mineralocorticoid excess
Ur Na <20 mEq/L
UrOsm< 300 mOsm/L
Normal
Non-renal
water loss
Skin,
sweat
GI loss
Renal water
loss
-Renal
disease
Low
Non-renal water
loss
Skin,
sweat
GI loss
Renal water
loss
-Renal tubular
disease
-Aldosteronism
-Diuretics
-Osmotic
diuresis
-Cushing’s
disease
-Diabetes
insipidus
-Diabetes
insipidus
-CAH
-Adrenal
failure
Hypernatremia
Symptoms & Signs
Water shift from ICF into ECF cell shrinkage
Only in patients with impaired thirst, restricted access to fluid
CNS : restlessness, lethargy, ataxia, irritability, tonic spasm, delirium,
seizure, coma (cell shrinkage subarachnoid hemorrhage)
Musculoskeletal : weakness
Cardio : Tachycardia, hypotension, syncope (hypovolemia)
Tissue : dry sticky mucous membrane, red swollen tongue, decreased
saliva, tears
Renal : oliguria
Metabolism : fever
Hypernatremia
Treatment
Hypernatremia with dehydration IV isotonic saline until
contracted ECF restored
Then free water administration
Consideration : not too rapid decline in serum Na and
osmolarity cerebral injury due to cellular swelling
Not exceed 8-10 mEq/d
Central DI DDAVP (1-desamino-8-D-arginine
vasopressin) IV or intranasal
Calculation
Total body Napre
Serum NaprexTBWpre
Serum Naprex 60 xBWpre
100
= Total body Napost
= Serum NapostxTBWpost
= Serum NapostxTBWpost
Eg. Serum Na = 160 mEq, BW = 50 kg
Serum Naprex 60 xBWpre = Serum NapostxTBWpost
100
160x (60/100) x50
= 140xTBWpost
TBWpost = 34.28 kg, TBWpre = (60/100)x50 = 30 kg
Water deficit = 4.28 L
Calculation
Total body Napre
Serum NaprexTBWpre
Serum Naprex 60 xBWpre
100
= Total body Napost
= Serum NapostxTBWpost
= Serum NapostxTBWpost
Eg. Serum Na = 160 mEq, BW = 50 kg
Serum Naprex 60 xBWpre = Serum NapostxTBWpost
100
160x (60/100) x50
= 150xTBWpost
TBWpost = 32 kg, TBWpre = (60/100)x50 = 30 kg
Water to be administered = 2 L / day
Topic
1) Content and composition of GI tract secretion
2) Sodium abnormalities : diagnosis and
management
3) Potassium abnormalities : diagnosis and
management
4) Impact of electrolyte abnormalities on organ
systems
Potassium
Average dietary intake 50-100 mEq/d (1-2 mEq/kg/d)
98% of total body K+ is in ICF
Only 2% in ECF, but important and need to be controlled
in narrow normal range 3.5-5.0 mEq/L
Renal excretion ranges 10-700 mEq/d
Renin-Angiotensin-Aldosterone system (RAAS) control K+
excretion in kidney
Hyperkalemia
K+> 5.0 mEq/L
Increase intake
•Oral supplement
•IV supplement
•Red cell lysis after
blood transfusion
•Endogenous load
(Hemolysis,
Rhabdomyolysis,
Crush injuries)
Increase releasing
from ICF
Impaired excretion
•Acidosis
•Rapid rise of
extracellular
osmolality
(hyperglycemia,
mannitol)
•Succinylcholine in
muscle disuse
atrophy
•K+ sparing diuretics
(spironolactone,
triamterene)
•ACEI
•Beta blockers
•Cyclosporin,
tacrolimus
•Renal failure
Hyperkalemia
Signs & Symptoms
Alteration of resting cell membrane potential impaired
depolarization &repolarization
GI : nausea, vomiting, intestinal colic, diarrhea
Neuro: weakness, paralysis, respiratory failure
Cardio : EKG change, arrhythmia, cardiac arrest
Tall peak T (symmetrical T wave)
Flat P wave
Prolong PR interval
Widen QRS complex sine wave
Ventricular fibrillation, asystole
EKG
Hyperkalemia
Treatment
Stop all infusion of potassium
EKG change : immediate effective therapy
10% Calcium gluconate 10 mL IV in 3-5 min
Reduce risk arrhythmia, antogonize depolarization effect
7.5% NaHco3 50-100 mEq IV in 10-20 min
Buffer ECF H+, shift H+ out & K+ in
50% glucose with insulin (RI) 10 units IV
Increase Na/K/ATPase, pump K+ into cell
No EKG change : effective therapy within hours
Potassium-binding resin :Sodium polystyrene sulfonateKayexalate
30 g +20% Sorbitol 50 mL oral or rectal
Bind K+ into gut lumen
Calcium polystyrene sulfonate: Kalimate 30 g +water 100 mL
Hemodialysis
Hypokalemia
K+< 3.5 mEq/L
Inadequate
intake
•Dietary
•K+ free IV fluid
•K+ deficient
TPN
K+
Excessive
excretion
•Hyperaldosteronism
•Medications
(diuretics)
•Mg depletion
cause renal K+
wastage
GI loss
•Direct loss of
K+ (diarrhea,
fistula)
•Renal loss of
K+ (gastric fluid
from vomiting
or high NG
output)
Intracellular
shift
•Metabolic
alkalosis
•Insulin
therapy
Hyp0kalemia
Signs & Symptoms
GI : Ileus, constipation
Neuro: decreased reflexes, fatigue, weakness, flaccid
paralysis with respiratory compromise
Cardio : EKG change, arrhthymia, cardiac arrest (higher
risk in patients with digoxin)
Depressed T waves
U waves
Atrial tachycardia with or without block
Atrioventricular dissociation
VT, VF
EKG
Hypokalemia
Treatment
Potassium supplement : IV , oral
Consideration
ECF volume status, renal perfusion
Mg depletion
Correct K+ before correct acidosis with HCO3 (eg. DKA) HCO3 will
worsen hypoK+
Limitation
Not exceed 0.3 mEq/kg/hr (BW 50kg, 15 mEq/hr)
If rate exceed 5 mEq/hr , should have EKG monitoring
High concentrate K+ irritate periphral vein : > 60 mEq/L need
central venous access
Potassium supplement
IV form
KCl
K2HPO3
10 mL = 20 mEq
20 mL = 20 mEq
Oral form
Elixir KCl
15 mL = 20 mEq
M. Potassium Citrate 15 mL = 10 mEq
Addi-K tab
10 mEq/tab
Topic
1) Content and composition of GI tract secretion
2) Sodium abnormalities : diagnosis and
management
3) Potassium abnormalities : diagnosis and
management
4) Impact of electrolyte abnormalities on organ
systems
Impact of electrolytes on organ
systems
Sodium
Control ECF osmolarity fluid shift from ICF
Cell dehydration/ cell swelling
Brain function
Potassium
Control cell membrane resting potential
Conduction in nerve, muscle esp. heart
Case
A 50-year-old 50 kg. man was diagnosed with duodenal
cancer with gastric outlet obstruction.
T 37.1c, P 88/min, R 18/min, BP 100/60 mmHg. He
appeared moderately dehydrate.
NG tube insertion revealed large amount of old food
particle in his stomach. Urine specific gravity was 1.030.
His laboratory results were Na+ 120 mEq/l, K+ 3.0 mEq/l, Cl95 mEq/l, HCO3- 29 mEq/l.
How should we prepare this patient for an operation?
Problems
1. Dehydration
2. Hyponatremia
3. Hypokalemia
4. Hypochloremic
5. Alkalosis
6. Gastric outlet obstruction
Gastric outlet obstruction
Not like others gut obstruction that also fluid loss from
small intestine, bile and pancreatic fluid
Loss of only
gastric fluid :
high in H+, Cl-
Dehydration
Hypochloremic
alkalosis
Renal
H+reabsorption
H+reabsorption /
K+ excretion
RAAS
Na+ reabsorption /
K+ excretion
Hypo
K+
K+reabsorption /
H+ excretion
Paradoxical
aciduria
Hyponatremia
Volume
status
High
-Increase
intake
-Postop
ADH
secretion
-Drugs
(antipsychotic,
TCA, ACEI)
Normal
Hyperglycemia/ma
nnitol
-Incr plasma
lipids/protein
(pseudohypoNa)
-SIADH
-Water intoxication
(TUR syndrome)
-Diuretics
Low
Decrease Na
intake
-low Na diet,
tube feeding
Increase Na
loss
GI loss
Renal loss
-Vomiting,
NG suction,
diarrhea
-Diuretics
-Primary renal
disease
-Cerebral salt
wasting
Hypokalemia
Inadequate
intake
•Dietary
•K+ free IV fluid
•K+ deficient
TPN
Excessive K+
excretion
•Hyperaldosteronism
•Medications
(diuretics)
•Mg depletion
cause renal K+
wastage
GI loss
•Direct loss of K+
(diarrhea,
fistula)
•Renal loss of K+
(gastric fluid
from vomiting
or high NG
output)
Intracellular shift
•Metabolic
alkalosis
•Insulin therapy
Management
Volume replacement with isotonic solution
NSS is preferred to correct hypoNa and hypoCl
Eg. NSS 1000 mL IV 300 mL/hr
Potassium replacement
After adequate urine output (0.5 ml/kg/hr)
Eg. Add IV KCl 40 mEq in IV fluid 1000 mL
Close monitoring of urine output
Retained foley catheter
Serial F/U of electrolyte after correction
Take Home Message
Total body Sodium ECF volume ; ≠ Serum Sodium
Hyponatremia /Hypernatremia
Change in ratio between total body Na and free water
Categorize by volume status iden cause correct
Potassium control cell membrane potential, effect
multiple organ systems
Need to control in normal range
Gastric outlet obstruction
HypokalemicHypochloremic, Metabolic alkalosis with
paradoxical aciduria