Abstract 12258: Out-of-hospital Cardiac Arrest With Initially Shockable Rhythm: What Are the Outcomes if No Shock is Given?
Background: Prompt defibrillation is critical for termination of ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) in out-of-hospital cardiac arrest (OHCA). For ethical reasons, the real impact of not shocking OHCA patients with a shockable rhythm is unlikely to be investigated in clinical trials and thus remains unknown.
Objectives: To describe demographics, pre-hospital characteristics, interventions, and outcomes in OHCA patients with an initially shockable rhythm who did and did not get shocked in the field in DFW ROC site.
Methods: We included all non-traumatic OHCA cases ≥18 years old with VF or VT as first known rhythms, who were treated and transported to a hospital within the DFW ROC site between 2006 - 2011. We report return of spontaneous circulation (ROSC) in the field and survival to hospital discharge for victims with and without shock delivered in the field. Multiple variable regression analysis assessed the association between shock delivery and ROSC in the field as well as survival.
Results: Included were 882 adult non-traumatic OHCA cases with VF or VT as first known rhythms; mean (±SD) age was 60 ± 15 years, 71% male, bystander witnessed 56%, bystander resuscitation attempt 43%, public arrest location 26%, EMS response time 4.7 ± 2.3 min, 26.9% (237) had ROSC in the field, 14.9% (131) survived to hospital discharge; 93.4% (824) of all patients were shocked, while 6.6% (58) were not shocked. Of the 6.6% (58) who were not shocked, 12.1% (7) achieved ROSC in the field and 8.6% (5) survived to hospital discharge. For those not shocked in the field, the unadjusted and adjusted odds ratios for ROSC were 0.354 (95% CI 0.158-0.791, p=0.011) and 0.189 (95% CI 0.039-0.911, p=0.038), respectively; and for survival to hospital discharge they were 0.522 (95% CI 0.205-1.331, p=0.173) and 0.498 (95% CI 0.088-2.810, p=0.430), respectively.
Conclusions: In the DFW ROC site, 6.6% of OHCA victims with an initially shockable rhythm did not receive a shock, which was significantly associated with decreased ROSC in the field. More patients survived who were shocked in the field, but this difference was not significant after adjustment for Utstein variables.
Author Disclosures: Y. Xiong: None. A.H. Idris: Research Grant; Significant; NIH/NHLBI.
- © 2015 by American Heart Association, Inc.