Cerebral blood flow fluctuation in neonatal respiratory distress and periventricular haemorrhage.

The relationship of cerebral blood flow fluctuation (CBFF) with periventricular haemorrhage (PVH) and respiratory distress syndrome (RDS) was studied in 35 preterm newborns. CBFF was defined as the interquartile range in the ensemble of pulses of a 20-s Doppler recording of CBF velocity (CBFV) in the internal carotid artery. We found a statistically significant increase in end diastolic CBFF in PVH and RDS. This increase was related to the mode of respiration (spontaneous or mechanically supported), the state of the ductus arteriosus, and the level of end diastolic CBFV. Differences before and after the onset of PVH were not found. In view of this, we conclude that RDS increases CBFF, that this increase is related to pleural pressure fluctuations, that these can be damped by mechanical ventilation, and that their propagation to the CBF is promoted by patency of the ductus arteriosus and foramen ovale. Whether the CBFF increase causes PVH, or is merely an expression of coincident RDS, remains a question that needs further investigation.