人工过度通气对颅脑手术病人脑氧代谢的影响

Effect of artificial hyperventilation on cerebral O_2 metabolism in patient with craniocerebral operation

目的 采用颈内静脉血气监测技术 ,观察不同程度的人工过度通气对颅脑手术病人脑氧代谢的影响。方法 对 36例颅脑手术患者进行过度通气 ,根据呼期末二氧化碳分压 (PCO2 )将病人分为A、B、C 3组 ,其PCO2 分别控制在 4 5、4 0和 3 5kPa。通气 1h后 ,同时采集动脉和颈内静脉血样 ,检测颈静脉血样饱和度 (SjO2 ) ,计算脑氧摄取 (CEO2 )、颈静脉血氧含量(CjO2 )和脑动静脉氧差 (AVDO2 )。结果 A、B组通气前后SjO2 、CEO2 、CjO2 和AVDO2 变化不大 ;C组通气后SjO2 和CjO2 降低 ,CEO2 增高 ,与基础值比较有显著性差异 (P <0 0 5或 0 0 1)。结论 深度过度通气 (PCO2 3 5kPa)可导致脑氧代谢障碍。维持PCO2 在 4 5～ 4

Objective To investigate the effect of various degrees of artificial hyperventilation on cerebral O 2 metabolism with the technique of jugular venous blood gas monitoring.Methods Thirty-six patients undergoing brain surgery were selected to be hyperventilated artificially,and those were randomly divided into three groups according to PCO 2.In group A,B and C, the PCO 2 were maintained at 4.5? 4.0 and 3.5kPa respectively.After hyperventilating for 1.0 hour, jugular bulb blood samples and radial arterial blood samples were taken and made gas analysis at the same time.Then cerebral oxygen extract(CEO 2),jugular venous oxygen concentration (CjO 2)and cerebral arterial-venous oxygen difference(AVDO 2)were calculated.Results In group A and B,saturation of jugular venous oxygen(SjO 2),CEO 2,CjO 2 and AVDO 2 remained unchanged during the ventilation.In group C,on following hyperventilation SjO 2and CjO 2 decreased,CEO 2 increased,which were statistically significant compared with the baselines( P <0.05 or 0.01).Conclusions Deep hyperventilation lead to disorders of cerebral O 2 metabolism.To keep the PCO 2 at 4.5～4.0 kPa could be a safe limit for hyperventilation therapy.