中度过度通气在静脉麻醉过程中增加脑乳酸外排的作用机制  

Mechanism of brain cerebral lactate efflux induced by moderate hyperventilation during intravenous anesthesia

作　　者：丁帅[1,2] 陈欣[2] 祝胜美[1] 

机构地区：[1]浙江大学附属第一医院麻醉科,浙江杭州310007 [2]杭州市中医院麻醉科

出　　处：《上海医学》2015年第6期507-511,共5页Shanghai Medical Journal

摘　　要：目的探讨中度过度通气在静脉麻醉过程中增加脑乳酸外排、影响脑内有氧代谢从而降低脑血流量的作用机制。方法选取30例准备行冠状动脉介入治疗的男性患者作为研究对象，进行对照交叉试验。患者经芬太尼或咪达唑仑随机静脉麻醉，手术前分别在动脉血二氧化碳分压≥50和〉25～30mmHg（1mmHg=0．133kPa，即通气不足和中度过度通气状态）时检测血流动力学和代谢指标并进行计算。结果中度过度通气状态下的动脉血二氧化碳分压、脑血流量、大脑中动脉平均血流速度、有效的脑灌注压、颈静脉球静脉血氧饱和度、颈静脉血氧分压、脑氧供、乳酸一氧指数和乳酸一葡萄糖指数均显著低于通气不足时（P值均〈0．01），平均动脉压、脑零流量压力、脑血管阻力、动脉血pH值、动脉血氧饱和度、动脉血氧分压、乳酸脑代谢率、氧摄取分数均显著高于通气不足时（P值分别〈0．01、0．05），氧的动脉静脉差异、葡萄糖的动脉一颈静脉差异、乳酸的动脉一颈静脉差异均显著大于通气不足时（P值均〈0．01）。中度过度通气与通气不足状态下血红蛋白水平、血液温度、氧脑代谢率和葡萄糖脑代谢率的差异均无统计学意义（P值均〉0．05）。结论中度过度通气会导致行静脉麻醉的心血管疾病患者的脑乳酸净流出量显著增加，脑血流量和颈静脉球血氧分压显著降低，提示临床相关浓度的低碳酸血症可能会损害脑有氧代谢水平。Objective To explore the mechanism of moderate hyperventilation which may increase lactate efflux, affect aerobic metabolism in the brain and reduce cerebral blood flow during intravenous anesthesia. Methods Thirty male patients who was going to undergo coronary artery interventional therapy were selected in this controlled crossover trial. Hemodynamic and metabolism parameters were detected when arterial partial pressure of carbon dioxide （paCO2） was 30 and 50 mmHg after intravenous anesthesia with fentanyl or midazolam. Results paCO2, cerebral blood flow, blood flow velocity of the middle cerebral artery, effective cerebral perfusion pressure, oxygen saturation of jugular vein ball, oxygen partial pressure of jugular vein ball, cerebral oxygen supply, lactate-oxygen index and lactate-glucose index in moderate hyperventilation were significantly lower than those in hypoventilation （all P〈0. 01）. However, mean arterial pressure, zero-flow pressure, cerebrovascular resistance, negative logarithm of H＋ concentration of arterial blood, arterial blood saturation, arterial partial pressure of dioxide, cerebral metabolic rate of lactate and oxygen extraction fraction in moderate hyperventilation were significantly higher than those in hypoventilation （P〈0.01, 0.05）. Arterio-jugular venous difference in oxygen, arterio-jugular venous difference in glucose and arterio-jugular venous difference in lactate in moderate hyperventilation were significantly greater than those in hypoventilation （all P〈0.01）. There were no significant differences in terms of hemoglobin concentration, blood temperature, oxygen cerebral metabolic rate or glucose cerebral metabolic rate between hyperventilation and hypoventilation （all P〉0.05）. Conclusion Net outflow Of lactic acid caused by moderate hyperventilation in the brain of the patients with cardiovascular disease in intravenous anesthesia will increased significantly, while cerebral blood flow and oxygen partial pressure of jugular vein ball will significant

关 键 词：静脉麻醉 过度通气 乳酸 

分 类 号：R614[医药卫生—麻醉学]