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%v 51%) and 36 weeks post conceptional age (26% v 25%), survived without oxygen dependency at 28 days (31% v 27%) and 36 weeks post conceptional age (58% v 52%), and developed acute renal failure. There were no statistically significant differences between other outcomes, except that fewer of the restricted group (19% v 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.