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Postnatal Weight Loss in Preterm Neonates <1500 g is Due to Isotonic Dehydration of the Extracellular Volume
Author(s) -
BAUER K.,
VERSMOLD H.
Publication year - 1989
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.1989.tb11280.x
Subject(s) - medicine , weight loss , extracellular fluid , hyponatremia , gestational age , birth weight , endocrinology , renal function , urine osmolality , low birth weight , dehydration , diuresis , extracellular , pregnancy , obesity , chemistry , biochemistry , biology , genetics
Bauer, K. and Versmold, H. (Division of Neonatology, Department of Obstetrics and Gynecology, University of Munich, Munich, FRG). Postnatal weight loss in preterm neonates < 1 500 g is due to isotonic dehydration of the extracellular volume. Acta Paediatr Scand Suppl 360: 37, 1989. Weight, extracellular volume (ECV, distribution volume of sucrose) and renal function were studied in 13 preterm infants at birth (age 6 h (2–12); median, range) and again when postnatal weight loss exceeded 5% of birth weight (age 84 (64–97) h). Gestational age was 28 (26–32) weeks, and birthweight was 1170 g (810–1455). The infants were nursed in incubators and mechanically ventilated. Fluid therapy allowed a weight loss of up to 10% of birthweight. Body weight decreased significantly from 1101 ± 2202g at birth to 1016 ± 2198 g at day 3 and ECV from 499 ± 155 ml to 413 ± 118 ml. Mean weight loss of 85 ± 50g was the same as mean ECV loss of 86 ± 48 ml, suggesting that postnatal weight loss is water loss from the ECV. Weight loss was preceeded by a marked increase in diuresis, exceeding fluid intake on day 2. Creatinine clearance did not change. The increased urine output led to a significant increase of sodium excretion without inducing hyponatremia but resulted in an isotonic reduction of ECV.