Weil Institute of Critical Care Medicine, Rancho Mirage, CA, USA.
Crit Care Med. 2010 Mar;38(3):910-5. doi: 10.1097/CCM.0b013e3181cc4944.
The current standard of manual chest compression during cardiopulmonary resuscitation requires pauses for rhythm analysis and shock delivery. However, interruptions of chest compression greatly decrease the likelihood of successful defibrillations, and significantly better outcomes are reported if this interruption is avoided. We therefore undertook a prospective randomized controlled animal study in an electrically induced ventricular fibrillation pig model to assess the effects of timing of defibrillation on the manual chest compression cycle on the defibrillation threshold.
Prospective, randomized, controlled animal study.
University-affiliated research laboratory.
Yorkshire-X domestic pigs (Sus scrofa).
In eight domestic male pigs weighing between 24 and 31 kg, ventricular fibrillation was electrically induced and untreated for 10 secs. Manual chest compression was then performed and continued for 25 secs with the protection of an isolation blanket. The depth and frequency of chest compressions were guided by a cardiopulmonary resuscitation prompter. Animals were randomized to receive a biphasic electrical shock in five different compression phases with a predetermined energy setting. A control phase was chosen at a constant 2 secs after discontinued chest compression. A grouped up-down defibrillation threshold testing protocol was used to compare the success rate at different coupling phases. After a recovery interval of 4 mins, the sequence was repeated for a total of 60 test shocks for each animal.
No difference in coronary perfusion pressure before delivering of the shock was observed among the six study phases. The defibrillation success rate, however, was significantly higher when shocks were delivered in the upstroke phase of manual chest compression.
Defibrillation efficacy is maximal when electrical shock is delivered during the upstroke phase of manual chest compression.
心肺复苏时，目前的手动胸外按压标准要求在进行节律分析和电击除颤时暂停。然而，胸外按压的中断大大降低了除颤成功的可能性，如果避免这种中断，会报告出更好的结果。因此，我们在电诱导的心室颤动猪模型中进行了一项前瞻性随机对照动物研究，以评估除颤时机对手动胸外按压周期对除颤阈值的影响。
前瞻性、随机、对照动物研究。
大学附属研究实验室。
约克夏-辛克莱杂种猪（Sus scrofa）。
在 8 只体重 24 至 31 公斤的雄性家猪中，用电击诱导心室颤动，并让其未经治疗持续 10 秒。然后进行手动胸外按压，并在隔离毯的保护下继续按压 25 秒。胸外按压的深度和频率由心肺复苏提示器指导。动物被随机分配在五个不同的按压阶段接受双相电冲击，采用预定的能量设置。选择一个恒定的 2 秒的控制阶段，即在停止胸外按压后 2 秒。采用分组上下除颤阈值测试方案比较不同耦合阶段的成功率。每个动物总共进行了 60 次测试电击，间隔 4 分钟恢复一次，重复该序列。
在给予电击之前，六个研究阶段的冠状动脉灌注压没有差异。然而，当在手动胸外按压的上升阶段给予电击时，除颤成功率显著更高。
当在手动胸外按压的上升阶段给予电击时，除颤效果最佳。
