Extracellular volume in preterm infants: influence of gestational age and colloids.

We assessed the effect of fresh frozen plasma (FFP) on extracellular volume (ECV) during the first few days of life in two groups of preterm infants, group 1 (gestational age < 30 weeks) and group 2 (gestational age 30–34 weeks). The infants were randomly assigned to one of two treatment groups, one receiving FFP, the other not; group 1 infants receiving no treatment (n = 8) and group 1 infants receiving FFP (n= 11), and group 2 infants receiving no treatment (n = 9) and group 2 receiving FFP (n = 10). FFP was given at a dose of 10 ml/kg daily during a two-hour period for the first three days of life. ECV was measured on day 1 before FFP was given and on day 4 by the distribution of bromide. There was a significant correlation between birth weight and initial ECV (r = 0.85, P < 0.001). In group 1 ECV was significantly higher than in group 2 (P < 0.02). In group 1 receiving no treatment mean weight loss and mean decrease in ECV were equal (84 g/kg and 78 ml/kg, respectively), but no correlation between the two parameters could be found (r = 0.68, P = 0.06). In the other study groups, mean weight loss was higher than mean decrease in ECV, with no correlation between weight loss and change in ECV. In group 1, no treatment, ECV reduction was 78 ± 79 ml/kg (mean ± S.D.), whereas in group 1, FFP, ECV increased (13 ± 96 ml/kg), indicating that FFP may attenuate ECV reduction in infants with a gestational age < 30 weeks. However, the difference was not significant (P = 0.056). The finding of the present study stresses the importance of careful assessment of hydration, including consideration of sodium balance and alterations of plasma osmolality, and body weight changes, in preterm infants during the first few days of life.