How do you calculate maintenance fluid rates for dogs and cats?
Common approaches are linear formulas — (30 × kg) + 70, 50 × kg, or 60 × kg mL/day — and allometric formulas that scale with metabolic weight: 132 × kg⁰·⁷⁵ for dogs and 80 × kg⁰·⁷⁵ for cats. As a rule of thumb, that lands near 2–6 mL/kg/hr for dogs and 2–3 mL/kg/hr for cats.
How is the dehydration deficit calculated?
Deficit (mL) = % dehydration × body weight (kg) × 10. A 10 kg dog that is 8% dehydrated needs roughly 800 mL to correct the deficit. Estimates: ~5% for mild dehydration, ~8% moderate, over 10% severe — always interpreted alongside your physical exam. This calculator replaces the deficit over 24 hours, a conservative approach; many clinicians replace 75–80% in the first day.
Should replacement fluids be used for maintenance?
Replacement crystalloids like LRS contain more sodium and less potassium than a patient normally loses, so running them long-term for maintenance risks hypernatremia and hypokalemia — especially in anorexic patients or those with vomiting and diarrhea. AAHA guideline options include commercial maintenance solutions, or replacement solution and D5W with potassium supplementation (13–20 mmol/L).