Randomised trial of fluid restriction in ventilated very low birthweight infants

Abstract

Background - Fluid restriction has been reported to improve survival of infants without chronic lung disease (CLD), but it remains unknown whether it reduces CLD in a population at high risk of CLD routinely exposed to antenatal steroids and postnatal surfactant without increasing other adverse outcomes. Aim - To investigate the impact of fluid restriction on the outcome of ventilated, very low birthweight infants. Study design - A randomised trial of two fluid input levels in the perinatal period was performed. A total of 168 ventilated infants (median gestational age 27 weeks (range 23-33)) were randomly assigned to receive standard volumes of fluid (60 ml/kg on day 1 progressing to 150 ml/kg on day 7) or be restricted to about 80% of standard input. Results - Similar proportions of infants on the two regimens had CLD beyond 28 days (56% υ 51%) and 36 weeks post conceptional age (26% υ 25%), survived without oxygen dependency at 28 days (31% υ 27%) and 36 weeks post conceptional age (58% υ 52%), and developed acute renal failure. There were no statistically significant differences between other outcomes, except that fewer of the restricted group (19% υ 43%) required postnatal steroids (p < 0.01). In the trial population overall, duration of oxygen dependency related significantly to the colloid (p < 0.01), but not crystalloid, input level; after adjustment for specified covariates, the hazard ratio was 1.07 (95% confidence interval 1.02 to 1.13). Conclusions - In ventilated, very low birthweight infants, fluid restriction in the perinatal period neither reduces CLD nor increases other adverse outcomes. Colloid infusion, however, is associated with increased duration of oxygen dependency.