Choosing Intravenous Fluids for Maintenance Therapy

Fluid Composition Recommendations

The American Academy of Pediatrics and Intensive Care Medicine recommend using isotonic balanced crystalloid solutions with appropriate glucose and potassium as the first-line choice for maintenance intravenous fluid therapy in acute and critically ill patients to reduce the risk of hyponatremia and minimize length of stay 1, 2
Isotonic solutions have sodium concentrations similar to plasma (135-144 mEq/L), and examples include PlasmaLyte and 0.9% sodium chloride 3
Balanced solutions should be favored over 0.9% sodium chloride, as they slightly reduce length of stay in critically ill patients (evidence level B) and acutely ill patients (evidence level A) 1, 4

Glucose should be included in maintenance fluids in sufficient amounts to prevent hypoglycemia, and blood glucose monitoring should be performed at least daily to guide glucose provision 1
Appropriate potassium should be added to maintenance fluids based on clinical status and regular monitoring to avoid hypokalemia 1

The total daily amount of maintenance fluid should include all sources, and fluid overload and cumulative positive fluid balance should be avoided to prevent prolonged mechanical ventilation and extended length of stay 1
Regular reassessment of fluid balance, clinical status, and electrolytes, especially sodium levels, is recommended at least daily 1

Using hypotonic solutions for maintenance therapy significantly increases the risk of hyponatremia 2, 3
Failing to account for all sources of fluid when calculating total maintenance volume can lead to "fluid creep" and overload 1

In patients with heart failure, renal failure, or hepatic failure, maintenance fluid volume should be restricted to 50-60% of the calculated volume using the Holliday and Segar formula 1
For patients at risk of increased ADH secretion, restricting maintenance fluid to 65-80% of the calculated volume should be considered 1