Multispecies · Multisystem · Clinical calculations
Fluid therapy calculations
Total plan equals resuscitation plus dehydration deficit plus maintenance plus ongoing losses. Keep the units explicit and the arithmetic boring.
Deficit in liters equals body weight in kilograms times percent dehydration expressed as a decimal. Maintenance for small animals approximates 2 to 3 mL per kilogram per hour, or the allometric 70 times body weight to the 0.75 power in kilocalories per day used as milliliters. Shock boluses are given in aliquots, commonly 10 to 20 mL per kilogram in dogs and 5 to 10 in cats, then reassessed rather than run to a fixed total. Replace deficits over 12 to 24 hours unless the patient has cardiac or renal disease. Chronic hyponatremia should not be corrected faster than roughly 0.5 mEq per liter per hour because of myelinolysis risk. Always show and check unit conversions before dosing.