FLUID & ELECTROLYTE THERAPY IN SURGERY
INTRODUCTION: Body Spaces
Intracellular
Extracellular
Intravascular
Total Body Wt (70kg)
50-60% Water (70 x 0.6=42L)
/ \
60% Intracellular (25L) 40% Extracellular (17L)
/ \
80% Interstitial (13L) 25% Intravascular (4L)
Plasma Osmolality = 2(Na) + Glucose/18 + BUN/2.8
For Adults: Input /Output
1. Normal Fluid Output / day
Urine - 1500 ml/day 1500ml
Cellular Metabolism – 400ml/day 400ml
Insensible losses – 10ml/kg body wt/day 700ml
Total losses per day = 2600ml
2. Basal Req/d (Adult) = 35 – 40 ml/Kg/ or 1500ml/msq (2500 – 3000ml)
Basal Req/d (Paediatric):
10 kg = 100ml/kg
10-20 kg = 1000ml + 50ml/kg over 10 kg
20-30 kg = 1500ml + 20ml/kg over 20 kg
3. Electrolyte Requirements / day (Adult)
Daily requirement 70kg
Sodium 1-2mmol/kg 70-140 mmol/d
Potassium 0.5-1 mmol/kg 35-70 mmol/d
Calcium 03.-0.5 mmol/kg 10mmol/d
Magnesium .35-.45 meq/kg 24.5-31.5 meq/d
(Paediatric): Na = 3- 5; K = 2- 3, Cl = 5-7 mmol/kg/d
Basal Req /d given as 1L N/S + 2L 5% D + 20 mmol of K to each L
, Composition of Body Fluids
Source Daily loss [ Na ] [K] [Cl] [HCO3]
Saliva 1000 30-80 20 70 30
Gastric 1000-2000 60-80 15 100 0
Pancreas 1000 140 5-10 60-90 40-100
Bile 1000 140 5-10 100 40
Small
2000-5000 140 20 100 25-50
Bowel
Colon 200-1500 75 30 30 0
Sweat 200-1000 20-70 5-10 40-60 0
Contents of commonly used IV fluids
[Na] [K] [Cl] [Dextrose] Other
Lactated
130 4 109 0 Lactate 28meq
Ringer's
Normal saline 154 0 154 0
D5LR 130 4 109 50g Lactate 28meq
D5NS 154 0 154 50g
D5.45NS 77 0 77 50g
D5W 0 0 0 50g
5% Albumin 145 <2 0 0 12.5g protein
ELECTROLYTES
Normal Serum Values:
Na 135-145 mmol
K 3.5-4.8 mmol
Cl 95-106 mmol
INTRODUCTION: Body Spaces
Intracellular
Extracellular
Intravascular
Total Body Wt (70kg)
50-60% Water (70 x 0.6=42L)
/ \
60% Intracellular (25L) 40% Extracellular (17L)
/ \
80% Interstitial (13L) 25% Intravascular (4L)
Plasma Osmolality = 2(Na) + Glucose/18 + BUN/2.8
For Adults: Input /Output
1. Normal Fluid Output / day
Urine - 1500 ml/day 1500ml
Cellular Metabolism – 400ml/day 400ml
Insensible losses – 10ml/kg body wt/day 700ml
Total losses per day = 2600ml
2. Basal Req/d (Adult) = 35 – 40 ml/Kg/ or 1500ml/msq (2500 – 3000ml)
Basal Req/d (Paediatric):
10 kg = 100ml/kg
10-20 kg = 1000ml + 50ml/kg over 10 kg
20-30 kg = 1500ml + 20ml/kg over 20 kg
3. Electrolyte Requirements / day (Adult)
Daily requirement 70kg
Sodium 1-2mmol/kg 70-140 mmol/d
Potassium 0.5-1 mmol/kg 35-70 mmol/d
Calcium 03.-0.5 mmol/kg 10mmol/d
Magnesium .35-.45 meq/kg 24.5-31.5 meq/d
(Paediatric): Na = 3- 5; K = 2- 3, Cl = 5-7 mmol/kg/d
Basal Req /d given as 1L N/S + 2L 5% D + 20 mmol of K to each L
, Composition of Body Fluids
Source Daily loss [ Na ] [K] [Cl] [HCO3]
Saliva 1000 30-80 20 70 30
Gastric 1000-2000 60-80 15 100 0
Pancreas 1000 140 5-10 60-90 40-100
Bile 1000 140 5-10 100 40
Small
2000-5000 140 20 100 25-50
Bowel
Colon 200-1500 75 30 30 0
Sweat 200-1000 20-70 5-10 40-60 0
Contents of commonly used IV fluids
[Na] [K] [Cl] [Dextrose] Other
Lactated
130 4 109 0 Lactate 28meq
Ringer's
Normal saline 154 0 154 0
D5LR 130 4 109 50g Lactate 28meq
D5NS 154 0 154 50g
D5.45NS 77 0 77 50g
D5W 0 0 0 50g
5% Albumin 145 <2 0 0 12.5g protein
ELECTROLYTES
Normal Serum Values:
Na 135-145 mmol
K 3.5-4.8 mmol
Cl 95-106 mmol
