Relation between arterial blood pressure and blood volume and effect of infused albumin in sick preterm infants.

The relation between directly measured arterial blood pressure and blood volume was studied in 61 sick preterm infants. Mean blood volume (derived from plasma volume [T1824 ten-minute albumin space] and hematocrit value) of 26 hypotensive infants (89.1 +/- 17.26 ml/kg) was not significantly different from that of 35 normotensive, but otherwise comparable, infants (91.4 +/- 14.57 ml/kg). There was no relation between arterial mean blood pressure and blood volume. Twenty-one infants with arterial mean blood pressure less than 30 mm Hg were given 1.0 g/kg of 10% salt-poor albumin. Significant increases in blood pressure occurred but were small in magnitude; more than one half of infants had arterial mean blood pressures persistently less than 30 mm Hg. Arterial/alveolar PO2 ratio decreased significantly with albumin infusion in six infants with hyaline membrane disease not receiving continuous distending-airway pressure, suggesting an association between infused albumin and impaired oxygen exchange.