MEASUREMENT OF NUTRIENT INTAKE BY DEUTERIUM DILUTION IN PREMATURE-INFANTS

To assess whether a simple nonrestrictive method of determining nutrie nt intake could be applied to premature infants, we compared actual me asured formula intake during a 7-day period with intake calculated fro m deuterium dilution in 13 hospitalized, growing, premature newborn in fants. An oral dose of deuterium oxide (D2O) was administered, and uri ne samples were analyzed by deuterium nuclear magnetic resonance spect rometry for D2O concentration. Using an exponential model, we calculat ed formula intake from the decline in D2O concentration during the 7-d ay study period. Intake as assessed by the deuterium model correlated well with actual intake (ra = 0.93; p <0.001). However, because the de uterium dilution model measures both dietary and nondietary water inta ke (metabolic and cutaneous water influx), deuterium dilution-derived intake exceeded actual intake by 25 +/- 18 ml/kg per day (16% +/- 11%) . When corrections were applied to account for nondietary water intake , deuterium dilution-derived nutrient intake (160 +/- 30 ml/kg per day ) closely approximated actual intake (155 +/- 17 ml/kg per day). If co rrections are made for nondietary water intake, the deuterium dilution method may be a useful nonrestrictive method of measuring nutrient in take in a variety of neonatal populations.