Literature Review: Care Transfer Shock Delays

   Berdowski J, Schulten RJ, Tijssen JG, et al. Delaying a shock after takeover from the automated external defibrillator by paramedics is associated with decreased survival. Resuscitation, Dec. 18, 2009 [E-pub ahead of print].

Abstract

   The purpose of this study was to investigate whether the takeover by advanced life support-trained ambulance paramedics from rescuers using an automated external defibrillator delays shocks, and if this delay is associated with decreased survival after out-of-hospital cardiac arrest (OHCA).

   Methods—[Authors] analyzed continuous ECG recordings of LIFEPAK AEDs and associated manual defibrillator recordings of OHCA of presumed cardiac cause, prospectively collected from July 2005 to July 2009. The primary outcome measure was survival to discharge. Among 693 patients treated with AEDs, 110 had a shockable initial rhythm and a shockable rhythm during ALS takeover. [Authors] measured the time interval between the expected shock if the AED would remain attached to the patient and the first observed shock given by the manual defibrillator [shock timing].

   Results—Survival was 62% (13/21) if the shock was given early (&llt;-20 secs.); 52% (11/21; odds ratio=0.68, ns) if given on time (-20 to 20 secs.); 29% (10/34; OR=0.26, 95% CI, 0.08–0.81; P=0.02) if the shock was 20–150 seconds delayed; and 21% (7/34; OR=0.16, 95% CI, 0.05–0.54; P=0.003) if the shock was delayed >150 seconds. The OR for trend was 0.41, 95% CI, 0.25–0.71; P=0.001. The association between shock timing and survival was significant for patients with more than 150 seconds shock delay (OR=0.19, 95% CI, 0.04–0.71; P=0.02) or for trend in shock timing (0.42, 95% CI, 0.20–0.84; P=0.02) after multivariable adjustment for prognostic factors age and slope of ventricular fibrillation. Conclusions—ALS takeover delays the next shock delivery in almost two-thirds of cases. This delay is associated with decreased survival.

Comment

   In an earlier column I presented the McMAID and pit crew methods that coordinate and choreograph the team approach to cardiac arrest resuscitation. Defining the roles and actions of each team member makes everything work more efficiently. This study takes that a step further. From the patient's perspective, the need for heart and brain circulation does not pause when one crew changes over for another; it is still essential to pay attention to the quality of CPR and timing of defibrillation. The authors here were able to show that delays in defibrillation are equally deadly whenever they occur.

   This also points out the importance of systemwide QI efforts. Only by examining both the first responder AED and the ALS monitor defibrillator can one see the possible delays. This requires all devices to be synchronized to coordinated universal time, a process to download and review all rhythm strips, and a person (or group) to review and report outcomes. This is especially challenging in tiered systems where BLS and ALS are performed by different organizations.

   The goal to improve cardiac arrest resuscitation rates is an effort that involves the entire system, from 9-1-1 through hospital care. Despite the difficulties, EMS systems should be looking at these interfaces between providers as carefully as they do individual provider performance.

   Angelo Salvucci, Jr., MD, FACEP, is an emergency physician and medical director for the Santa Barbara County and Ventura County (CA) EMS agencies.