[Gastrointestinal hormones during minimal enteral feeding of sick premature infants]. / Hormonas gastrointestinales en la estimulación enteral mínima en neonatos prematuros enfermos.

OBJECTIVE: To measure gastrointestinal hormonal response (GHR) with minimal enteral feeding (MEF) in sick premature infants. METHODS: Forty-one babies birth weight < 1800 g receiving total parenteral nutrition or intravenous solutions entered the study. They were distributed in two groups: group I: 26 infants (early enteral feeding < or = 5 d) and group II = 15 infants (late enteral feeding = 10-14 d). A diluted special formula was used as MEF starting with 1 mL hourly with daily increments of 1 mL up to 120 mL. Basal and final determinations of GHR were done before and after the MEF. RESULTS: Both groups were similar in birth weight, postnatal age, and trophism. There were intragroup differences between basal and final GHR for all hormones in both groups. Subgroups by gestational age (< or = 32 vs > 32 weeks) and trophism (< or = 1250 vs > 1250 g) also showed basal-final differences. There were no complications related to the MEF. CONCLUSIONS: MEF favors secretion of gastrointestinal hormones in sick premature infants. Early MEF seems to be preferable to late one since it allows a faster secretion related to volume of the formula. MEF did not increase abdominal complications in our infants.

Usefulness of fractional excretion of sodium in critically ill pre-term newborns.

The purpose of this prospective study was to measure the fractional excretion of sodium (FENa) in critically ill pre-term newborns (PTNB) in order to determine its cut point in the diagnosis of acute renal failure (ARF). This study included 52 newborns and was conducted from May, 1994 to May, 1995. Patients were divided in two groups: patients without ARF in group A (n = 47) and patients with ARF in group B (n = 5). No statistically significant differences were found in birth weight, extrauterine life span, serum sodium levels, urine creatinine and urinary volumes between the two groups, but there was a difference in gestational age, urinary sodium concentration and serum creatinine levels. Sensitivity and specificity were determined, and the critical level of FENa was 4% or greater for ARF diagnosis. The average FENa value for Group A was 1.4 +/- 1.4% with a median of 0.92%. In Group B, average FENa was 6.9 +/- 2.9% with a median of 8.5% (P < 0.001). We conclude that FENa is a valuable tool for the assessment of renal function in critically-ill PTNB, in spite of all other factors present in this population that could modify its values.