Impact of Changes in Resuscitation Practice on Survival and Neurological Outcome after Out-of-Hospital Cardiac Arrest Resulting From Non-Shockable Arrhythmias
Background—Out-of-hospital cardiac arrest (OHCA) claims millions of lives worldwide each year. OHCA survival from shockable arrhythmias (ventricular fibrillation/tachycardia) improved in several communities after implementing American Heart Association resuscitation guidelines that eliminated "stacked" shocks and emphasized chest compressions. "Non-shockable" rhythms are now the predominant presentation of OHCA, upon which the benefit of such treatments is uncertain.
Methods and Results—We studied 3960 patients with nontraumatic OHCA from non-shockable initial rhythms treated by pre-hospital providers in King County, WA over a 10 year period. Outcomes during a 5 year intervention period after adoption of new resuscitation guidelines were compared to the previous 5 year historical control period. The primary outcome was 1-year survival. Patient demographics and resuscitation characteristics were similar between control (n=1774) and intervention (n=2186) groups, among whom 471/1774 (27%) versus 742/2186 patients (34%), respectively, achieved return of circulation (ROSC); 82 (4.6%) versus 149 (6.8%) were discharged from hospital, 60 (3.4%) versus 112 (5.1%) with favorable neurological outcome; 73 (4.1%) versus 135 (6.2%) survived 1-month, and 48 (2.7%) versus 106 patients (4.9%) survived 1-year; all p≤0.005. After adjusting for potential confounders, the intervention period was associated with an improved odds of 1.50 (95% confidence interval (CI) 1.29, 1.74) for ROSC; 1.53 (CI 1.14, 2.05) for hospital survival, 1.56 (CI 1.11, 2.18) for favorable neurological status; 1.54 (CI 1.14, 2.10) for 1-month survival, and 1.85 (CI 1.29, 2.66) for 1-year survival.
Conclusions—Outcomes from OHCA due to non-shockable rhythms, though poor by comparison with shockable rhythm presentations, improved significantly after implementing resuscitation guideline changes, suggesting their potential to benefit all presentations of OHCA.
- Received August 26, 2011.
- Accepted February 27, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited