Maintenance Fluid Calculation for Adults

Calculation Method

The American Society for Parenteral and Enteral Nutrition recommends using the Holliday-Segar formula for calculating maintenance fluid requirements, which allocates 100 mL/kg/day for the first 10 kg, 50 mL/kg/day for the next 10 kg, and 25 mL/kg/day for the remaining weight 1
For adults, particularly those over 60 years, the recommended baseline is 30-35 mL/kg/day, resulting in a total daily fluid intake of 2,010-2,345 mL for a 67 kg patient 2, 3, 4

The Society of Critical Care Medicine recommends using isotonic crystalloid solutions, such as 0.9% sodium chloride or balanced crystalloids, for maintenance therapy to reduce the risk of hospital-acquired hyponatremia 5, 6, 1
Balanced crystalloids may be preferred over 0.9% saline to avoid hyperchloremic acidosis, although evidence is not definitive in adults 6

The European Society of Intensive Care Medicine recommends reducing maintenance fluid volume to 50-60% of the calculated amount in patients with heart failure, renal failure, or hepatic failure 5, 1
The American College of Critical Care Medicine recommends increasing maintenance fluids for patients with fever, adding 2-2.5 mL/kg/day for each 1°C rise above 37°C 4, 1

The National Institute of Clinical Excellence recommends standard electrolyte requirements per day, including 1-3 mmol/kg/day of sodium, 1-3 mmol/kg/day of potassium, and 2-4 mmol/kg/day of chloride 6, 4, 1

The Intensive Care Medicine society recommends daily reassessment of fluid balance, serum sodium, and other electrolytes, as well as clinical status and urine output 5, 1, 7

The World Journal of Emergency Surgery recommends avoiding fluid overload, which independently predicts prolonged mechanical ventilation, increased ICU length of stay, and higher mortality 5, 1, 7
The Clinical Nutrition society recommends avoiding hypotonic maintenance fluids in acutely ill adults, as they significantly increase hyponatremia risk 6