Stool water loss in very-low-birth-weight neonates

Fluid requirements in very-low-birth-weight (VLBW) infants include compensation for renal, insensible (skin and lung), and stool losses and provision for fluid retained for growth. Current estimates of stool water losses in VLBW infants are based on measurements established in term neonates. Therefore, the water content of 24-hour stool collections were determined in 11 healthy VLBW male infants on full enteral feeds and compared to the working norms. The neonates in this study were less than 2 weeks old with a mean +/- SD birth weight and gestational age of 1,311 +/- 112 g and 30.8 +/- 1.5 weeks, respectively. They were receiving only enteral formula feedings of 100 ml/kg/day or more with no parenteral fluid supplementation. The mean +/- SD number of stools and water content of the stools was 2.7 +/- 2.0/day and 7.2 +/- 4.0 ml/kg/day, respectively. There was a significant correlation (r = 0.696, p less than 0.02) between gestational age at birth and number of stools per day, but the correlation between stool water loss per day, gestational age, volume of feedings per day, and birthweight was not significant. Based on this study, 7 ml/kg/day is a reasonable estimate of daily stool water loss in VLBW babies.