Fluid Repletion (IVF)
See critical care quick reference for bolus doses by weight.
TBW
TBW = 0.6 x weight (kg); 2/3 intra, 1/3 extracellular. 1/4 of extracellular is vascular.
Maintenance
- Calculation 1
- 100 cc/kg/d (4cc/kg/h) 1st 10 kg
- 50 cc/kg/d (2cc/kg/h) 2nd 10 kg
- 20 cc/kg/d (1cc/kg/h) each kg > 20
- Calculation 2
- 1500 cc/m2/d (bsa (m2) = sqr rt [wt (kg) x ht (cm)]/3600
Insensible losses = 300-400 cc/m2/d
Adult Standard: D5 0.45%NS at 75-125 mL/hr + 20meq/L of KCl
Deficit: % dehydration x baseline weight
Daily volume needed = maintenance + deficit - fluid already given (i.e. boluses)
Hourly rate daily vol/24 hr
(or correct 1/2 of deficit in first 8 hr, remainder in next 16)
Pediatric
- Maintenance fluid default: D5-1/2NS plus 20 mEq of potassium
Electrolytes
Maintenance Na = 3 mEq/kg/d; K = 2 mEq/kg/d
Deficit = [desired - measured mEq/L] x fD x wt (kg)
fD (distribution factor) Na = 0.6, K = 0.6, Cl = 0.2-0.3, HCO3 = 0.5
(Maintenance + deficit)/daily volume = concentration of electrolyte in fluid to be given
4mL/kg of H2O lost, ups Na by 1meq
NS = 154 mEq Na/L, 1/2 NS = 77 mEq/L, 1/4NS = 38 mEq/L
