IV Maintenance Fluid Rate Recommendations
The rate of IV maintenance fluids should be calculated using the Holliday and Segar formula, with restriction to 65-80% of the calculated volume in acutely and critically ill patients at risk of increased ADH secretion, and to 50-60% in patients with heart failure, renal failure, or hepatic failure to avoid fluid overload. 1, 2
Standard Calculation Method
- The Holliday and Segar formula remains the standard method for calculating maintenance fluid requirements 1:
- 100 mL/kg/day for the first 10 kg
- 50 mL/kg/day for the next 10 kg
- 20 mL/kg/day for each kg above 20 kg
Volume Modifications for Special Populations
- For acutely and critically ill patients at risk of increased ADH secretion, restrict maintenance fluid volume to 65-80% of the calculated volume to avoid hyponatremia and fluid overload 1, 2
- For patients with heart failure, renal failure, or hepatic failure, restrict maintenance fluid volume to 50-60% of the calculated volume to prevent fluid overload 1, 2
- In postoperative patients, intravenous fluid therapy is usually unnecessary beyond the day of operation, except for those undergoing upper gastrointestinal and pancreatic procedures 1
Fluid Composition Considerations
- Use isotonic balanced crystalloid solutions with appropriate glucose and potassium as first-line maintenance fluid therapy 1, 2
- Isotonic solutions (sodium concentration 135-144 mEq/L) reduce the risk of hyponatremia compared to hypotonic solutions 1, 2, 3
- Balanced solutions should be favored over 0.9% sodium chloride to slightly reduce length of stay 1, 2
Monitoring Requirements
- Reassess fluid balance, clinical status, and electrolytes (especially sodium) at least daily 1
- Monitor blood glucose at least daily to guide glucose provision in maintenance fluids 1
- Track potassium levels regularly when providing maintenance fluids with potassium supplementation 1
Common Pitfalls to Avoid
- Failing to account for all sources of fluid when calculating total maintenance volume can lead to "fluid creep" and overload 1, 2
- Using hypotonic solutions significantly increases the risk of hyponatremia, particularly in children 2, 4, 3
- Excessive fluid administration can lead to complications including pulmonary edema, tissue edema, and impaired wound healing 1
- Fluid restriction resulting in deficit can be as detrimental as excess, causing decreased venous return, diminished tissue perfusion, and increased blood viscosity 1
Total Daily Fluid Calculation
- The total daily amount of maintenance fluid should include all sources 1:
- IV fluids
- Blood products
- All IV medications (both infusions and bolus drugs)
- Arterial and venous line flush solutions
- Enteral intake
- (Does not include replacement fluids and massive transfusion)