A Trial of an Impedance Threshold Device in Out-of-Hospital Cardiac Arrest

Abstract

BACKGROUND 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. METHODS 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). RESULTS 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. CONCLUSIONS 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.)

Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest

“…The baseline survival rate was estimated from patients with a first recorded rhythm of ventricular fibrillation or pulseless ventricular tachycardia who received at least two shocks in previous ROC trials. 22,23 The projected difference in survival with amiodarone was estimated from a previous trial database 7 and was the comparison for which this trial was powered.…”

The Association of Health Status and Providing Consent to Continued Participation in an Out‐of‐hospital Cardiac Arrest Trial Performed Under Exception From Informed Consent

“…Survival status and neurologic function at hospital discharge and beyond has become a standard endpoint for cardiac resuscitation trials, but access to this data is limited by patients/ families who decline consent and those patients who are lost to follow-up. 6,7 The rate of missing outcome data due to declined consent in cardiac arrest trials performed under EFIC is poorly reported. The LINC Trial (mechanical CPR vs. standard CPR) reported a 0.3% (seven of 2,593) consent withdrawal rate, and 0.6% of patients had missing outcome data for their survival to hospital discharge analysis.…”

What is new in the 2015 American Heart Association guidelines, what is recycled from 2010, and what is relevant for emergency medicine in Canada

“…15 The combination of ITD with active compression-decompression CPR may be a reasonable alternative to conventional CPR in settings with available equipment and properly trained personnel. 16,17 Conventional manual chest compressions remain the standard of care for the treatment of cardiac arrest, but mechanical chest compression devices may be a reasonable alternative for use by properly trained personnel.…”