Calcium and phosphate requirements of preterm infants who require prolonged hyperalimentation.

Preterm infants require large amounts of calcium and phosphate to maintain skeletal mineralization during prolonged hyperalimentation. It is impossible to supply the amount of calcium and phosphate normally acquired transplacentally (150 mg/kg/day of calcium and 80 mg/kg/day of phosphate) with reasonable volumes of a single hyperalimentation solution of a physiological pH. We recently encountered calcium phosphate precipitates plugging our hyperalimentation catheters as we tried to raise the calcium concentration above 20 mEq of calcium per liter of hyperalimentation solution. Such a solution supplies 50 mg/kg/day of calcium when run at 125 mL/kg/day. In an attempt to circumvent this problem, we are currently using two hyperalimentation solutions--one high in calcium and the other high in phosphates--run alternately for 12-hour periods. This regimen supplies 80 mg/kg/day of calcium.