Stoner Jason, Martin Gerard, O'Mara Kevin, Ehlers Joseph, Tomlanovich Michael
Department of Emergency Medicine, Henry Ford Hospital, Detroit, MI, USA.
Acad Emerg Med. 2003 Mar;10(3):187-91. doi: 10.1111/j.1553-2712.2003.tb01988.x.
Refractory ventricular fibrillation (VF) is a complication of severe hypothermia. Despite mixed experimental data, some authors view bretylium as the drug of choice in hypothermic VF. Bretylium was removed from Advanced Cardiac Life Support guidelines, and, to date, efficacy of amiodarone in hypothermia is unknown.
To compare defibrillation rates from hypothermic VF after drug therapy with amiodarone, bretylium, and placebo.
This was a randomized, blinded, and placebo-controlled laboratory experiment. Thirty anesthetized dogs were mechanically ventilated and instrumented to monitor coronary perfusion pressure (CPP), rectal core temperature, and electrocardiogram (ECG). Animals were cooled to 22 degrees C or the onset of spontaneous VF. Ventricular fibrillation was induced as needed with a transthoracic AC current. Cardiopulmonary resuscitation (CPR) was initiated and animals were randomized (n = 10 each group) to receive amiodarone 10 mg/kg (A), bretylium 5 mg/kg (B), or placebo (P) intravenously. CPR was continued while monitoring for chemical defibrillation. Rewarming was limited to removal from the cold environment. After 10 minutes, up to three escalating defibrillatory shocks were administered. Hemodynamic monitoring continued after resuscitation. Return of spontaneous circulation (ROSC) was defined as a sustainable ECG rhythm generating a corresponding arterial pressure tracing lasting a minimum of 15 minutes. Sample size permitted 80% power to detect a 60% difference in conversion rate between groups.
CPR was adequate based on CPP > 15 mm Hg in all animals. Mean (+/-SD) CPP was 35.3 +/- 18.8 mm Hg with an overall lower trend in the amiodarone group (p = 0.06). Baseline variables were similar between groups. No instance of chemical defibrillation was noted. There was no significant difference in ROSC rates between groups. Resuscitation rates were: amiodarone = 1/10, bretylium = 4/10, and placebo = 3/10 (p = 0.45).
In this model of severe hypothermic VF, neither amiodarone nor bretylium was significantly better than placebo in improving the resuscitation rate.
难治性室颤是严重低温的一种并发症。尽管实验数据不一，但一些作者认为溴苄铵是低温性室颤的首选药物。溴苄铵已从高级心脏生命支持指南中删除，并且迄今为止，胺碘酮在低温情况下的疗效尚不清楚。
比较胺碘酮、溴苄铵和安慰剂药物治疗后低温性室颤的除颤率。
这是一项随机、双盲和安慰剂对照的实验室实验。30只麻醉犬进行机械通气并安装监测冠状动脉灌注压（CPP）、直肠核心温度和心电图（ECG）的仪器。将动物冷却至22摄氏度或出现自发性室颤。根据需要用经胸交流电诱发室颤。启动心肺复苏（CPR），并将动物随机分组（每组n = 10），静脉注射胺碘酮10 mg/kg（A组）、溴苄铵5 mg/kg（B组）或安慰剂（P组）。在监测化学除颤的同时继续进行CPR。复温仅限于将动物从寒冷环境中移出。10分钟后，给予多达三次递增的除颤电击。复苏后继续进行血流动力学监测。自主循环恢复（ROSC）定义为可持续的心电图节律，产生相应的动脉压波形，持续至少15分钟。样本量允许有80%的把握度检测出组间转化率有60%的差异。
所有动物的CPP>15 mmHg，表明CPR充分。平均（±标准差）CPP为35.3±18.8 mmHg，胺碘酮组总体呈较低趋势（p = 0.06）。各组间基线变量相似。未观察到化学除颤的情况。各组间ROSC率无显著差异。复苏率分别为：胺碘酮组 = 1/10，溴苄铵组 = 4/10，安慰剂组 = 3/10（p = 0.45）。
在这种严重低温性室颤模型中，胺碘酮和溴苄铵在提高复苏率方面均不比安慰剂有显著优势。
