Department of Emergency Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
N Engl J Med. 2011 Sep 1;365(9):798-806. doi: 10.1056/NEJMoa1010821.
The impedance threshold device (ITD) is designed to enhance venous return and cardiac output during cardiopulmonary resuscitation (CPR) by increasing the degree of negative intrathoracic pressure. Previous studies have suggested that the use of an ITD during CPR may improve survival rates after cardiac arrest.
We compared the use of an active ITD with that of a sham ITD in patients with out-of-hospital cardiac arrest who underwent standard CPR at 10 sites in the United States and Canada. Patients, investigators, study coordinators, and all care providers were unaware of the treatment assignments. The primary outcome was survival to hospital discharge with satisfactory function (i.e., a score of ≤3 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating greater disability).
Of 8718 patients included in the analysis, 4345 were randomly assigned to treatment with a sham ITD and 4373 to treatment with an active device. A total of 260 patients (6.0%) in the sham-ITD group and 254 patients (5.8%) in the active-ITD group met the primary outcome (risk difference adjusted for sequential monitoring, -0.1 percentage points; 95% confidence interval, -1.1 to 0.8; P=0.71). There were also no significant differences in the secondary outcomes, including rates of return of spontaneous circulation on arrival at the emergency department, survival to hospital admission, and survival to hospital discharge.
Use of the ITD did not significantly improve survival with satisfactory function among patients with out-of-hospital cardiac arrest receiving standard CPR. (Funded by the National Heart, Lung, and Blood Institute and others; ROC PRIMED ClinicalTrials.gov number, NCT00394706.).
阻抗阈值设备（ITD）旨在通过增加胸腔内负压程度来增强心肺复苏（CPR）期间的静脉回流和心输出量。先前的研究表明，在 CPR 期间使用 ITD 可能会提高心搏骤停后患者的存活率。
我们比较了在美国和加拿大的 10 个地点进行标准 CPR 的院外心搏骤停患者使用主动 ITD 与使用 sham ITD 的效果。患者、研究人员、研究协调员和所有护理提供者均不知道治疗分组。主要结局是存活至出院且功能良好（即改良 Rankin 量表评分为≤3，范围为 0 至 6，分数越高表示残疾程度越大）。
在纳入分析的 8718 例患者中，4345 例随机分配至 sham ITD 治疗组，4373 例分配至主动设备治疗组。sham-ITD 组中有 260 例患者（6.0%）和 active-ITD 组中有 254 例患者（5.8%）达到了主要结局（调整序贯监测的风险差异，-0.1 个百分点；95%置信区间，-1.1 至 0.8；P=0.71）。次要结局也没有显著差异，包括到达急诊室时自发循环恢复的比例、存活至入院和存活至出院的比例。
在接受标准 CPR 的院外心搏骤停患者中，使用 ITD 并未显著提高功能良好的存活率。（由美国国立心肺血液研究所等资助；ROC PRIMED ClinicalTrials.gov 编号，NCT00394706。）
