脑氧代谢监测在脑外伤术中过度通气时的价值

目的观察术中过度通气对急性颅脑外伤患者氧代谢的影响,探讨脑氧代谢监测的价值。方法 36例急性颅脑外伤患者,手术中分别于正常通气（PETCO25.0 Kpa）、轻度（PETCO25.0~4.0 Kpa）、中度（PETCO23.5 Kpa）、重度（PETCO23.0 Kpa）过度通气并稳定20 min后同步采集外周动脉和颈静脉球部血样行血气分析,监测SjvO2并计算Da-jvO2。结果随着PETCO2的降低,SjvO2下降,Da-jvO2增加,在中度过度通气时均在安全范围,但至重度过度通气时,有10例SjvO2低于50%,24例Da-jvO2高于9 ml%,显示部分患者脑缺氧。结论脑氧代谢监测可指导脑外伤患者术中过度通气,重度过度通气时可导致脑氧供需失衡,故在颅脑手术麻醉中应避免重度过度通气。

Value of Cerebral Oxygen Metabolism Monitoring on Hyperventilation in Patients with Acute Brain Trauma Undergoing Neurosurgery

Objective To observe the effect of hyperventilation on the cerebral oxygen metabolism and the value of cerebral oxygen metabolism monitoring in patients with acute brain trauma neurosurgery under general anesthesia Methods Thirty-six acute brain trauma patients underwent intravenous general anesthesia and brain surgery.Mechanical ventilation was regulated to maintain PETCO2 at 5.0 Kpa(normal ventilation),5.0～4.0 Kpa(slight hyperventilation),3.5 Kpa(moderate hyperventilation),and 3.0 Kpa(severe hyperventilation)during the operation.Each level of PETCO2 was maintained for 20 min then the radial arterial blood samples and jugular bulb blood samples were taken simultaneously for blood gas analysis.SjvO2 was evaluated,and Da-jvO2 was calculated. Results Following the PETCO2 declined,SjvO2 decreased and Da-jvO2 increased,they were still within normal limits during moderate hyperventilation.During severe hyperventilation,there were 10 cases SjvO2<50% and 24 cases Da-jvO2>9 ml%,which showed their brain hypoxia. Conclusions Cerebral oxygen metabolism monitoring can be used to guide hyperventilation on patients with acute brain trauma undergoing neurosurgery.Severe hyperventilation influences the balance of cerebral oxygen supply and consumption during the injured head surgery,and hence severe hyperventilation should not be used during anesthesia for brain surgery.