Abstract 18274: Comparative Effectiveness of Stacked versus Single Shock Therapy for In-Hospital Cardiac Arrest: Insights from the Get With the Guidelines-Resuscitation Registry

Abstract

Background: Among patients with cardiac arrest due to ventricular tachycardia or ventricular fibrillation (VT/VF), guidelines emphasize single shock protocols to minimize interruptions in chest compressions that may impair patient outcomes. The adoption and impact of single shock protocols on survival of in-hospital VT/VF arrest is unknown. Methods: In the Get With The Guidelines - Resuscitation multicenter observational registry, we identified 4,114 adults with in-hospital cardiac arrest due to VT/VF between 2004 and 2012, an immediate post-shock rhythm of VT/VF following the initial defibrillation attempt, and a second defibrillation attempt within 3 minutes of the first shock. The time interval in minutes from the initial shock to second shock was used to define stacked shock (time interval of 0 to 1 minute) and single shock protocols (time interval of 2 to 3 minutes). We first evaluated temporal trends in the use of stacked versus single shock protocols. We then used hierarchical regression adjusting for patient arrest characteristics and comorbidities while accounting for clustered observations by hospital to determine the association between stacked versus single shocks for VT/VF and survival to discharge. For this analysis, we restricted our cohort to the 2,984 (72.5%) patients with VT/VFarrest occurring at one of 150 hospitals with the use of both stacked and single shock approaches and at least 10 events during the study period. Results: The proportion of patients receiving a single shock protocol for VT/VF following an initial defibrillation attempt doubled from 25% in 2004 to more than 50% in 2012. Compared with patients treated with stacked shocks, treatment with single shocks was associated with a lower risk-adjusted survival to discharge (odds ratio 0.81, 95% confidence interval 0.68 to 0.98, P=0.03). Conclusion: Among adults with in-hospital VT/VFarrest, use of single shocks has increased since 2004 in accordance with guideline recommendations. However, compared with stacked shocks, single shocks for VT/VF was associated with decreased odds of survival to discharge. These observational findings suggest further investigation is needed to define the optimal defibrillation strategy for management of in-hospital VT/VF arrest.