Ristagno Giuseppe, Tang Wanchun, Chang Yun-Te, Jorgenson Dawn B, Russell James K, Huang Lei, Wang Tong, Sun Shijie, Weil Max Harry
Weil Institute of Critical Care Medicine, 35100 Bob Hope Dr, Rancho Mirage, CA 92270, USA.
Chest. 2007 Jul;132(1):70-5. doi: 10.1378/chest.06-3065. Epub 2007 Jun 5.
We address the quality of chest compressions and the impact on initial defibrillation or initial chest compressions after sudden death.
Ventricular fibrillation was induced by occlusion of the left anterior descending coronary artery in 24 domestic pigs with a mean (+/- SD) weight of 40 +/- 2 kg. Cardiac arrest was left untreated for 5 min. Animals were then randomized to receive chest compressions-first or defibrillation-first and were further randomized to "optimal" or "conventional" chest compressions. A total of four groups of animals were investigated using a factorial design. For optimal chest compressions, the anterior posterior diameter of the chest was reduced by 25%, representing approximately 6 cm. Only 70% of this depth, or approximately 4.2 cm, represented conventional chest compressions. Chest compressions were delivered with a mechanical chest compressor. Defibrillation was attempted with a single biphasic 150-J shock. Postresuscitation myocardial function was echocardiographically assessed.
Coronary perfusion pressures and end-tidal Pco(2) were significantly lower with conventional chest compressions. With optimal chest compressions, either as an initial intervention or after defibrillation, each animal was successfully resuscitated. Fewer shocks were required prior to the return of spontaneous circulation after initial optimal chest compressions. No animals were resuscitated when conventional chest compressions preceded the defibrillation attempt. When defibrillation was attempted as the initial intervention followed by conventional chest compressions, two of six animals were resuscitated.
In this animal model of cardiac arrest, it was the quality of the chest compressions, rather then the priority of either initial defibrillation or initial chest compressions, that was the predominant determinant of successful resuscitation.
我们探讨了胸外按压的质量以及其对猝死患者初始除颤或初始胸外按压的影响。
通过闭塞24头体重平均为40±2千克的家猪的左前降支冠状动脉诱发心室颤动。心脏骤停后不予处理5分钟。然后将动物随机分为先进行胸外按压组或先进行除颤组，并进一步随机分为“最佳”或“传统”胸外按压组。采用析因设计共研究了四组动物。对于最佳胸外按压，胸部前后径缩小25%，约为6厘米。此深度的70%，即约4.2厘米，代表传统胸外按压。使用机械胸外按压装置进行胸外按压。尝试用单次150焦耳双相电击除颤。复苏后通过超声心动图评估心肌功能。
传统胸外按压时冠状动脉灌注压和呼气末二氧化碳分压显著降低。采用最佳胸外按压，无论是作为初始干预措施还是在除颤后，每只动物均成功复苏。初始最佳胸外按压后恢复自主循环前所需的电击次数较少。在除颤尝试前进行传统胸外按压时，无动物复苏成功。当以除颤作为初始干预措施随后进行传统胸外按压时，6只动物中有2只复苏成功。
在这个心脏骤停动物模型中，成功复苏的主要决定因素是胸外按压的质量，而非初始除颤或初始胸外按压的先后顺序。
