RESUMO
The routine management of head injury includes hyperventilation to produce hypocapnis with arterial CO2 tension 25~30 torr. But a decrease in cerebral blood flow with hypocapnia may result in cerebral ischemia. Our study was to evaluate the change of cerebral blood flow during hyperventilation in halthane anesthesia. The jugular venous oxygen saturation(SjvO2), arterio-venous oxygen content difference(CaO2-CjvO2), and oxygen extraction ratio(O2ER) were used as criteria of cerebral ischemia with reduced cerebral blood flow. The results are as follows: 1) SjvO2 was lower in group 2(PaCO2=22.8torr) than group 1(PaCO2=30.3 torr). 2) CaO2-CjvO2 and O2ER were higher in Group 2 than group 1. 3) No more increased possibility of cerebral ischemia with reduced cerebral blood flow was observed Group 2 than group 1.