犬心跳骤停复苏后脑和全身氧供需关系的观察

Study on the relationship between cerebral and systemic oxygen delivery and uptake after resuscitation from cardiac arrest in dogs

目的 观察和比较犬心跳骤停 (CA)复苏后脑和全身氧利用率 (O2 UC)的变化。方法 5只犬采用经胸壁电击致室颤 /心跳骤停 (VF/CA) 8min ,开胸心肺复苏 (OCCPR)恢复自主循环 (RSC)后同时观察 4h内脑和全身O2 UC的变化。结果 5只犬均CPR成功后维持稳定的血流动力学状态 ,仅RSC后 12 0min心输出量 (CO)较CA前明显降低 (2 1± 0 .8L/minvs 3 4± 1 4L/min ,P <0 0 5 )。RSC后 30min脑O2 UC即显著高于CA前 (0 5 7± 0 11vs 0 43± 0 0 8,P <0 0 5 ) ,RSC后 6 0、12 0和 2 40min时脑O2 UC则渐进性升高 ,且非常显著高于CA前 (0 6 5± 0 0 9、0 72± 0 0 9和 0 78± 0 0 6vs 0 43± 0 0 8,P均 <0 0 1) ;而直至RSC后 12 0min全身O2 UC才显著高于CA前 (0 36± 0 10vs 0 2 0± 0 0 5 ,P <0 0 5 )。结论 CA经OCCPR后脑和全身均发生氧供相对于氧需的不足 ,而且脑氧供需失衡的发生较全身更早、更严重 ,提示CPR后应力求尽早改善脑氧输送 。

Objective To study and compare the relationship between cerebral and systemic oxygen delivery and uptake following resuscitation from cardiac arrest.Methods In five dogs ventricular fibrillation/cardiac arrest(VF/CA) was induced by external transthoracic electric shock and then maintained for 8 minutes.Resuscitation was conducted by using open chest cardiopulmonary resuscitation(OCCPR).Cerebral and systemic oxygen utilization coefficient(O 2UC) were simultaneously determined before CA(baseline) and 30,60,120 and 240 min after return of spontaneous circulation(RSC).Results All five dogs were resuscitated successfully and maintained stable hemodynamic variables after RSC,except for cardiac output(CO) at 120 min significantly less than baseline value(2.1±0.8 L/min vs 3.4±1.4 L/min, P <0.05).Cerebral O 2UC was significantly higher at 30 min after RSC than baseline value(0.57±0.11 vs 0.43±0.08, P <0.05)and then increased progressively at 60,120 and 240 min(0.65±0.09,0.72±0.09 and 0.78±0.06 vs 0.43±0.08, P <0.01 respectively).However,systemic O 2UC did not markedly increase until 120 min after RSC(0.36±0.10 vs 0.20±0.05, P <0.05),and its value reached 0.5 at 240 min.Conclusions Inadequate cerebral and systemic oxygen delivery in relation to oxygen uptake exists following resuscitation from VF/CA.The mismatching of oxygen delivery to uptake in the brain might take place more early and seriously than in the whole body,suggesting that oxygen transport to the brain should be improved as soon as possible after CPR.Monitoring of cerebral oxygen metabolism in cardiopulmonary-cerebral resuscitation(CPCR) is clinically important.