Minimizing pre- and post-shock pauses during the use of an automatic external defibrillator by two different voice prompt protocols. A randomized controlled trial of a bundle of measures

Background Previous large retrospective analyses have found an association between duration of peri-shock pauses in cardiopulmonary resuscitation (CPR) and survival. In a randomized trial, we tested whether shortening these pauses improves survival after out-of-hospital cardiac arrest (OHCA). Methods Patients with OHCA between May 2006 and January 2014 with shockable initial rhythm, treated by first responders, were randomized to two automated external defibrillator (AED) treatment protocols. In the control protocol AEDs performed post-shock analysis and prompted rescuers to a pulse check (Guidelines 2000). In the experimental protocol a 15 s period of CPR during and after charging of the AED was added to the voice prompts and CPR was resumed immediately after defibrillation (modification of the Guidelines 2005). Survival was assessed at hospital admission and discharge. Results Of 1174 OHCA patients, 456 met the inclusion criteria: 227 were randomly assigned to the experimental protocol and 229 to the control protocol. The experimental group experienced shorter pre-shock pauses (6 [5–11] s vs. 20 [18–23] s; P < 0.001), and shorter post-shock pauses (7 [6–9] s vs. 27 [16–34] s; P < 0.001). Similar proportions of patients survived to hospital admission (experimental: 62% vs. control: 65%; RR [95%CI] 0.96 [0.83–1.10], P = 0.51), and hospital discharge (experimental: 42% vs. control: 38%; RR [95%CI] 1.09 [0.87–1.37], P = 0.46). Conclusion In patients with OHCA and shockable initial rhythms, treatment with AEDs with the experimental protocol shortened pre-shock and post-shock CPR pauses, and increased overall CPR time, but did not improve survival to hospital admission or discharge. Clinical trial registration http://www.isrctn.com unique identifier: ISRCTN72257677.