Leng C T, Berger R D, Calkins H, Lardo A C, Paradis N A, Halperin H R
Division of Cardiology, Department of Medicine, The Johns Hopkins Medical Institutions, The Johns Hopkins University, Baltimore, Md, USA.
Circulation. 2001 Aug 7;104(6):723-8. doi: 10.1161/hc0701.092217.
There is increasing evidence that defibrillation from prolonged ventricular fibrillation (VF) before CPR decreases survival. It remains unclear, however, whether harmful effects are due primarily to initial countershock of ischemic myocardium or to resultant postdefibrillation rhythms (ie, pulseless electrical activity [PEA] or asystole).
We induced 15 dogs into 12 minutes of VF and randomized them to 3 groups. Group 1 was defibrillated at 12 minutes and then administered advanced cardiac life support (ACLS); group 2 was allowed to remain in VF and was subsequently defibrillated after 4 minutes of ACLS; group 3 was defibrillated at 12 minutes, electrically refibrillated, and then defibrillated after 4 minutes of ACLS. All group 1 and 3 animals were defibrillated into PEA/asystole at 12 minutes. After 4 minutes of ACLS, group 2 and 3 animals were effectively defibrillated into sinus rhythm. The extension of VF in group 2 and 3 subjects paradoxically resulted in shorter mean resuscitation times (251+/-15 and 245+/-7 seconds, respectively, versus 459+/-66 seconds for group 1; P<0.05) and improved 1-hour survival (10 of 10 group 2 and 3 dogs versus 1 of 5 group 1 dogs; Fisher's exact, P<0.005) compared with more conservatively managed group 1 subjects.
Precountershock CPR during VF appears more conducive to resuscitation than CPR during postcountershock PEA or asystole. The intentional induction of VF may prove useful in the management of PEA and asystolic arrests.
越来越多的证据表明，在心肺复苏（CPR）前对长时间心室颤动（VF）进行除颤会降低生存率。然而，尚不清楚有害影响主要是由于缺血心肌的初始电击，还是由于除颤后的心律（即无脉电活动[PEA]或心搏停止）。
我们将15只犬诱导发生12分钟的VF，并将它们随机分为3组。第1组在12分钟时进行除颤，然后给予高级心脏生命支持（ACLS）；第2组保持VF状态，随后在ACLS 4分钟后进行除颤；第3组在12分钟时进行除颤，再次电除颤，然后在ACLS 4分钟后进行除颤。所有第1组和第3组动物在12分钟时除颤后均转为PEA/心搏停止。在ACLS 4分钟后，第2组和第3组动物有效地除颤转为窦性心律。与管理更为保守的第1组相比，第2组和第3组受试者VF的延长反而导致平均复苏时间缩短（分别为251±15秒和245±7秒，而第1组为459±66秒；P<0.05），并提高了1小时生存率（第2组和第3组的10只犬中有10只存活，而第1组的5只犬中有1只存活；Fisher精确检验，P<0.005）。
VF期间的电击前CPR似乎比电击后PEA或心搏停止期间的CPR更有利于复苏。故意诱导VF可能在PEA和心搏停止性心脏骤停的管理中有用。
