异氟烷麻醉对失血性休克血液循环和氧代谢的影响

摘要

目的 研究异氟烷麻醉对失血性休克(HS)血液循环和氧代谢的影响.方法 巴马小型猪16只,随机分为两组(n=8):清醒对照组(C组)和麻醉实验组(A组).两组猪分别于清醒和异氟烷麻醉两种状态下在15 min内按全身血容量的40%(即按30 mL/kg计算)匀速放血制备休克模型,监测放血前和放血后4 h内不同时间点的肺动脉温度(TP)、心率(HR)、平均动脉压(MAP)、中心静脉压(CVP)、平均肺动脉压(MPAP)、肺动脉楔压(PAWP)、心输出量(CO)、混合静脉血氧饱和度(SmvO2)及血气指标;计算每搏输出量(SV)、体循环阻力(SVR)、氧摄取量(Ca-vO2)、氧供(DO2)、氧耗(VO2)和氧摄取率(O2ER);记录每头猪的生存时间.结果 HS发生后,C组和A组HR分别增快至(193±19)次/min和(126±16)次/min,其后C组逐渐下降,A组变化较小;C组MAP和CO下降后回升较快、幅度较大,于HS 90 min分别回升至80 mm Hg和1.5 L/min以上,而A组回升不明显;但两组SVR增加较一致,且A组MPAP降低后回升较明显.HS导致两组DO2和VO2均分别降低至200 mL/min和150 mL/min以下,但A组下降并维持在更低水平,其O2ER、Ca-vO2和乳酸(LA)依然较低,SmvO2较高;两组猪在4 h内均存活.结论 异氟烷麻醉下,HS机体血流动力学应激代偿反应明显减弱,心血管系统受抑明显,氧供减少,但氧耗降低更显著,氧动力学失衡明显减轻.%Objective To study the effects of isoflurane anesthesia on blood circulation and oxygen metabolism in swine model of hemorrhagic shock (HS). Methods 16 healthy Bama miniature pigs were randomized into two groups ( n = 8, each group) : awaken control group ( C ) and anesthesia experimental group (A). Venous blood (30 mL/g) was continuously withdrawn over 15 minutes in anesthetized and unanesthetized swine to establish HS model. Pulmonary arterial temperature ( TP), heart rate (HR) , mean arterial pressure (MAP) , central venous pressure (CVP) , mean pulmonary artery pressure ( MPAP) , pulmonary artery wedge pressure ( PAWP) and cardiac output ( CO) , saturation of mixed venous blood ( SmvO2 ) and blood gas analysis were recorded at the pro - bleed ( HS 0 min) and different HS times; The stroke volume (SV) , systemic vascular resistance (SVR) , oxygen uptake ( Ca - vO2 ) , oxygen delivery ( DO2 ) , oxygen consumption ( VO2 ) , and the oxygen extraction ratio( O2ER) were calculated; survival time was recorded in all the pigs. Results HR of group C and group A increased to (193 ±19) bpm and (126 ±16) bpm respectively at 15 min after HS , then the group C decreased gradually, while the variation of HR in group A was smaller. MAP and CO increased more rapidly in group C than in group A after HS, which exceeded 80 mm Hg and 1. 5 L/min respectively at 90 min after HS. No difference was found in SVR between two groups, and MPAP increased more significantly in group A. HS resulted in significant reduction in DO2 and VO2, which decreased below 200 mL/min and 150 mL/min respectively. Lower levels were kept in group A, and O2ER, Ca - vO2 and LA were still lower, SmvO2 was higher in group A. The pigs of two groups all survived within 4 h. Conclusion Isoflurane significantly attenuates the stress compensatory response of hemodynamics and depresses the cardiovascular system obviously; oxygen supply and oxygen consumption decrease simultaneously, but the imbalance of oxygen dynamics is attenuated in isoflurane anesthesia state.