[Does the capacity for autoregulation of cerebrovascular circulation depend on gestational age?]

Changes of blood velocity in the right internal carotid artery (measured by transfontanellar pulsed Doppler) in relation to therapeutically induced changes of mean arterial blood pressure (measured oscillometrically) were used to evaluate autoregulatory capacity of cerebral blood flow in 17 neonates (540-3800 g). Preterm infants less than 32 gestational weeks (n = 11) didn't autoregulate, while the capacity of autoregulation was significantly better in neonates greater than 31 gestational weeks (n = 6). Regarding their disturbed autoregulation there was no difference between normotensive (n = 4) and hypotensive (n = 7) preterm infants less than 32 gestational weeks.