Pre- and postoperative fluid management in infancy.

The fluid and electrolyte management of the infant either before or following surgery is not difficult if the several principles are carefully followed: (1) Fluid requirements include maintenance therapy, correction of ongoing losses, and replacement of deficit losses. (2) Calculation for fluid requirements in the postoperative period will include maintenance therapy, correction of ongoing losses, and provision of fluid lost by internal shifts. (3) Maintenance needs for fluid in infants equals 100 to 120 mL/kg per 24 hours, and Na+ at 3 mEq/kg per 24 hours and K+ at 2 to 3 mEq/kg per 24 hours are needed. (4) Infants with pyloric stenosis should be anticipated to have hypokalemic, hypochloremic metabolic alkalosis, and dehydration. These electrolyte abnormalities should be corrected before surgery is performed. A pyloromyotomy is not an emergency procedure. (5) Ileostomy losses can equal 90 mEq/L of Na+ and up to 110 mEq/L of HCO3. Thus, adequate fluid replacement results in volume depletion and metabolic acidosis. (6) Children whose nutritional status is marginal and whose bowels cannot be used for nutrient absorption should receive their fluid and electrolyte needs as part of a total parenteral nutrition program.