Randomized trial of two levels of fluid input in the perinatal period - effect on fluid balance, electrolyte and metabolic disturbances in ventilatedVLBW infants

The aim of this study was to determine whether fluid restriction does indee d significantly increase acute adverse effects. One-hundred-and-sixty-eight ventilated infants, median gestational age 27 wk (range 23-33) and birthwe ight 953 g (range 486-1500), entered into a randomized controlled trial of two fluid regimes. Infants on regime A were to be prescribed 60 ml/kg of fl uids on day 1 which was gradually increased over the first week to 150 ml/k g, infants on fluid regime B were to be prescribed approximately 20% less f luid over the first week. Daily fluid input and output were recorded. Serum electrolytes, bilirubin, creatinine and urine osmolalities were measured d aily. Arginine vasopressin levels were assessed on days 1, 3 and 5. Episode s of jaundice, hypoglycaemia and hypotension requiring treatment were noted . Infants on regime B actually received overall 11% and, in the first 4 day s, 19% less fluid than those on regime A (p < 0.001). There were no statist ically significant differences :in the occurrence of episodes of jaundice, hypotension, hypoglycaemia, hypernatraemia or hyponatraemia between infants on the two regimes. Although the infants on regime B had significantly hig her urine osmolalities and lower urine output for most of the perinatal per iod, their median creatinine and arginine vasopressin levels did not differ significantly from those on regime A. We conclude that fluid restriction t o less than 90% of usual maintenance fluids is not associated with an exces s of acute adverse effects.