Cerebral blood flow velocity in newborn infants with asphyxia.

A pulsed-Doppler real-time technique was used to assess the anterior cerebral artery (ACA) flow velocity in 30 asphyxiated infants during the first 5 days after birth. Thirty healthy term infants were also studied as controls. Peak systolic flow velocity (PSFV), end diastolic flow velocity (EDFV), mean flow velocity (MFV), and pulsatility index (PI) were measured. Mean PI values of the ACA of the asphyxiated and control groups were 0.63 +/- 0.05 vs 0.71 +/- 0.04 (p less than 0.001) on the first day; 0.64 +/- 0.03 vs 0.70 +/- 0.05 (p less than 0.001) on the third day and 0.69 +/- 0.04 vs 0.70 +/- 0.04 (p greater than 0.05) on the fifth day of life. The asphyxiated group also had significantly higher EDFV and MFV than those of control group until the 5th day of life. The low PI values of asphyxiated infants were mainly due to an increase in EDFV. These results suggest that the cerebrovascular resistance of asphyxiated infants, as reflected by the PI, is low during the first 3 days of life, indicating an increase in cerebral blood flow. With this technique, we can repeatedly and safely evaluate the cerebral hemodynamic changes in asphyxiated newborn infants.