RENAL FUNCTION IN INFANTS < 1250 G (VLBW) IN THE FIRST THREE DAYS OF LIFE

Abstract

Renal function has been measured extensively in larger and older preterm infants. We studied 16 VLBW infants during the first three days of life. Eight infants were studied with 50 mg/kg boluses of inulin followed by infusions of 0.1 mg/kg/min. The other eight received 100 mg/kg and 0.2 mg/kg/min, respectively. The mean inulin levels were 19.5± 5.96 mg/dl (mean ± SD) and 65.0 ± 59.8 mg/dl, respectively. Timed urines were collected for 4 to 7 hrs and inulin clearances (IN) calculated in standard fashion. An attempt was made to allow a daily weight loss of 1.5-3.5% of birthweight. The gestational age was 28.5 ± 2.2 weeks and the birthweight, 990 ± 158 G. The results are not different between protocols and are combined. The daily change in values was not significant. IN did not correlate with either urine flow nor IV rates. Individual IN values ranged from .039 to 1.54 ml/kg/min. 9 of 16 infants had average IN > .3 ml/kg/min. IN and FeNa in VLBW infants < 72 hours old are lower than in older infants. *Fractional sodium excretion. One study coincident with furosemide treatment was omitted.