Randomised controlled trial of postnatal sodium supplementation on body composition in 25 to 30 week gestational age infants

Abstract

Aims-To compare the eVects of early and delayed sodium supplementation on body composition and body water compartments during the first two weeks of postnatal life. Methods-Preterm infants of 25-30 weeks' gestation were stratified and randomly assigned according to gender and gestational age, to receive a sodium intake of 4 mmol/kg/day beginning either on the second day after birth or when weight loss of 6% of birthweight had been achieved. Daily sodium intake, total fluid intake, energy intake, urine volume, and urinary sodium excretion were recorded. Total body water was measured by H 2 18 O dilution on days 1, 7, and 14, and extracellular fluid volume by sodium bromide dilution on days 1 and 14. Results-Twenty four infants received early, and 22 delayed, sodium supplementation. There were no significant diVerences between the groups in body water compartments on day 1. In the delayed group, but not the early group, there was a significant loss of total body water during the first week (delayed −44 ml/kg, p=0.048; early 6 ml/kg, p=0.970). By day 14 the delayed, but not the early group, also had a significant reduction in extracellular fluid volume (delayed −53 ml/kg, p=0.01; early −37 ml/kg, p=0.2). These changes resulted in a significant alteration in body composition at the end of the first week (total body weight: delayed 791 ml/kg; early 849 ml/kg, p=0.013). By day 14 there were once again no significant diVerences in body composition between the two groups. Conclusions-Body composition after preterm birth is influenced by the timing of introduction of routine sodium supplements. Early sodium supplementation can delay the physiological loss of body water that is part of normal postnatal adaptation. This is likely to be of particular relevance to babies with respiratory distress syndrome. A tailored approach to clinical management, delaying the introduction of routine sodium supplements until there has been postnatal loss of body water, is recommended. (Arch Dis Child Fetal Neonatal Ed 2000;82:F24-F28)

Standardized Parenteral Nutrition in Preterm Infants: Early Impact on Fluid and Electrolyte Balance

“…Over the last years, batch-produced standardized parenteral nutrition (SPN) bags have become easily available in neonatal intensive care units (NICUs) and the routine use of SPN is considered as an optimal means of quickly achieving the recommended protein and energy intakes after delivery [2,3] . However, transition to the extrauterine environment is often associated with major changes of body water composition in the premature baby and individualization of fluid and electrolyte intakes has been regarded as the best policy to avoid metabolic disturbances, especially hypernatremic dehydration [4][5][6] . Some retrospective investigations have explored early biochemical blood responses in preterm neonates on individual- ized parenteral nutrition (IPN) versus SPN, but none have prospectively compared these two nutritional regimes for changes in body fluid homeostasis in the very preterm infant [7,8] .…”

Infusionstherapie bei Neugeborenen, Säuglingen und Kindern

“…Es konnte gezeigt werden, dass eine Natriumsubstitution wäh-rend dieser Phase dem physiologischen postpartalen Gewichtsverlust entgegenwirkt und die respiratorische Morbidität erhöht [25]. Aus diesem Grund sollte die Natriumzufuhr initial auf ein Minimum beschränkt werden.…”

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