Abstract 20019: Incidence of Errant Shock Delivery in Out-of-hospital Cardiac Arrest Resuscitation
Introduction: Defibrillation is used to convert ventricular fibrillation and tachycardia (VF/VT) to a perfusing sinus rhythm. However, rhythm analysis is subjective and shocks may be delivered errantly on rhythms that do not warrant nor positively respond to defibrillation. We sought to assess the rate and factors associated with errant shock delivery.
Hypothesis: We hypothesized that cases lacking VF/VT would receive a shock in the prehospital environment, and that errant shock delivery would occur more often in younger and female patients, as well as cases that were witnessed and those that occurred in public locations.
Methods: We obtained IRB approval before commencing this study. Eligible cases of EMS-treated, nontraumatic OHCA spanned 2010-2014 at the Pittsburgh site of the Resuscitation Outcomes Consortium and contained at least one EMS-delivered shock. We excluded cases that did not receive any shocks. We analyzed all instances of EMS-delivered shocks in custom Matlab software. Pre- and post-shock rhythms were assessed for all shocks. Return of an organized rhythm (ROOR) was noted for every shock. Patient characteristics were obtained via patient care report review. We utilized t-tests with an alpha value of 0.05.
Results: A total of 461 cases received at least one shock and contained a total of 1,377 analyzable shocks. Of these shocks, 1246 (90.5%) had VF/VT, and 131 (9.5%) had non-VF/VT. Errant shocks were delivered in a total of 91 (19.9%) cases. Errant shocks were most often the second shock delivered in the case. Demographic data was available for 457 (99.1%) of cases. ROOR occurred in 769 (55.8%) shocks.
Errant shock delivery was not significantly associated with patient age (p = 0.79), sex (p = 0.14), location (p= 0.83), or witnessed status (p = 0.63).
Conclusions: Errant shock rate was 9.5% and occurred in 19.9% of all cases. These shocks were not associated with common demographic data. Further work will examine other possible causes for errant shock delivery.
Author Disclosures: A.C. Koller: None. D.D. Salcido: Research Grant; Modest; Laerdal Foundation Grant. Research Grant; Significant; 5K12HL109068-04. S.E. Tisherman: None. M.L. Sundermann: None. J.J. Menegazzi: Research Grant; Modest; 1R01HL117979-01A1.
- © 2015 by American Heart Association, Inc.