Objective: To study the relationship between the resistance index (RI) of the anterior cerebral artery and hypoxic ischemic encephapathy (HIE) in neonates for the purpose of finding out a method of diagnosing and predicting HIE and its prognosis.
Method: The anterior cerebral artery blood flow velocity waveform (aCAFV) of neonates was recorded by a continuous Doppler technique and RI value was measured. 230 observations on 67 cases of high risk neonates and 534 on 182 normal neonates were performed. The mean value of RI and its standard deviation in normal neonates chosen served as control. The relationship between the standardized incidence of abnormal RI of the anterior cerebral artery and HIE was studied in high risk neonates.
Result: In normal neonates (control group), RI was 0.62 +/- 0.09, and was in positive correlation (r = 0.72, P < 0.05) with the days after birth. The normal aCAFV was a regular waveform. In high risk neonates, the standardized incidence of abnormal RI in the neonates most likely to be attacked by HIE (A group) was significantly higher than that in control group (P < 0.001), but there was no significant difference between the other babies (B group) and control group (P > 0.05). However, the standardized incidence of abnormal RI in the A group was also significantly higher than that in the B group (P < 0.001). In the cases who were severely attacked by HIE, the standardized incidence of irregular waveform was the highest. Furthermore, when irregular aCAFV waveform appears, the incidence of pernicious complication of HIE and mortality of neonates were significantly increased in all cases.
Conclusion: The abnormal RI value of anterior cerebral artery implies the existence of HIE in neonates. The prognosis is poor when irregular blood flow waveform appears.