Regulation of cerebral blood flow velocity in nonasphyxiated, very low birth weight infants with hyaline membrane disease.

Previous studies of cerebral blood flow (CBF) and blood flow velocity regulation in stressed neonates, both term and preterm, have suggested that CBF is pressure passive. These studies are in conflict with data obtained from fetal and newborn animals. To determine if autoregulation of CBF is present in preterm infants, we studied eight very low birth weight infants (gestational age, 29.1 +/- 1.5 weeks; birth weight, 1117 +/- 278 g), all of whom had hyaline membrane disease that necessitated mechanical ventilation. None of the infants suffered from perinatal asphyxia, intraventricular hemorrhage, or patent ductus arteriosus. All infants demonstrated appropriate changes in cerebral blood flow velocity (CBFV) in response to changes in arterial oxygen content and pCO2. CBFV was not affected by changes in systemic mean arterial blood pressure. The data indicate that nonasphyxiated very low birth weight infants regulate their CBF in a manner similar to that observed in adults.