Comparison of the effect of two fluid input regimens on perinatal lung function in ventilated infants of very low birthweight

Fluid overload worsens respiratory failure; conversely, fluid restriction h as been associated with a higher survival rate without chronic lung disease . We therefore hypothesised that fluid restriction in the perinatal period might improve lung function in ventilated, prematurely born infants of very low birthweight. As a consequence, we compared in a randomised trial the e ffect of two fluid regimes on perinatal lung function. On one regime infant s were to receive 60 ml/kg on day 1, increasing to 150 ml/kg by day 7, and on the other regime approximately 25% less fluid waste be prescribed. Lung function was assessed by measurement of functional residual capacity (FRC) and compliance. Measurements were made daily on days 1 to 5 and then on day 7. Ninety infants, median gestational age 28 weeks (range 23-33), were inc luded in the study. There were no significant differences between the two g roups regarding their gestational age or birthweight, or in the proportions who received antenatal steroids or postnatal surfactant. The infants on th e restricted regime received significantly less fluid (P < 0.01). The only significant differences in lung function between the two groups, however, w ere that the infants on the restricted regime had a higher mean compliance on day 3, but thereafter the difference was reversed. Colloid intake, howev er, unfavourably affected lung function, total colloid intake being negativ ely correlated with both the area under the curve of birth-adjusted FRC (P = 0.003) and compliance (P = 0.001). Conclusion We conclude that early fluid restriction appears to have very li ttle impact on perinatal lung function.