Abstract 181

Aim of the study was investigate the relationship between blood volume (BV), systolic blood pressure (SBP) and the effect of volume expansion in preterm infants after birth.

Subjects: BV (Evans blue) and SBP (Doppler) were measured in 32 mechanically ventilated and in 63 non-ventilated preterm infants with birth weights of 750 to 1499 g and gestational age of 26-30 wks within the first two hours of birth.

Results: The mean BV of the 95 infants was 79 ± 13 ml/kg and the mean SBP was 43 ±8 mmHg. In the 32 ventilated infants, BV averaged 76±10 ml/kg and SBP was 40±7 mmHg. SBP was 35±8 mmHg in 22 hypovolemic infants (BV range 52 to 69 ml/kg) and 44±7 mmHg in 50 normovolemic infants (BV range 70-90 ml/kg). A positive relationship between SBP and BV existed only for BV <70 ml/kg. Nineteen infants with SBP <35 mmHg (BV 68±13 ml/kg) were given 10 ml/kg of Serum (Biseko®) over 30 minutes. Serum infusion increased SBP by 6±5 mmHg (P<0.05) in 11 hypovolemic infants (BV <70 ml/kg) and by 2±4 mmHg in 8 normovolemic infants. The increase in SBP was inversely related to blood volume (r=0.54) values before volume expansion.

Statistics: paired t-test, wilcoxon rank-test; mean ±ISD.

Conclusions: 1. Our results indicates that volume expansion increases blood pressure only if BV is low (<70 ml/kg). 2. If there is no little response to volume expansion, treatment with catecholamines should be considered.