Abstract 206: Cardiopulmonary Resuscitation Process Measures Associated With Return of Spontaneous Circulation in Non-Shockable Out-of-Hospital Cardiac Arrest

Abstract

Purpose: Survival rates after non-shockable out-of-hospital cardiac arrest (OHCA) remain low despite advances in resuscitation. Cardiopulmonary resuscitation (CPR) process measures may inform treatment strategies. We hypothesized that CPR process measures would be associated with return of spontaneous circulation (ROSC) and patient electrocardiogram (ECG) transitions. Methods: We obtained defibrillator monitor data for emergency medical service (EMS)-treated non-shockable OHCA from the Resuscitation Outcomes Consortium (ROC), an OHCA research network (U.S./Canada). We extracted ECG data from EMS defibrillator files and parsed cases into compression-free analyzable segments using custom MATLAB software. Two data abstractors classified segment rhythms as PEA, asystole, ventricular fibrillation (VF), pulseless ventricular tachycardia (PVT), or ROSC. We calculated CPR process measures (average rate, depth, duration, leaning proportion, chest compression fraction, and duty cycle) for CPR bouts preceding every ECG segment. We used mixed effects models controlling for subject to test associations between individual CPR process measures and the bout-level outcomes ROSC and shockable rhythm. Results: We analyzed 1893 cases consisting of 7981 CPR bouts. Case initial rhythms were asystole (68.2%), PEA (24.9%), or NSA-AED (6.9%). Segment rhythm classifications were asystole (78.1%), PEA (20.4%), ROSC (5.5%), VF (1.4%), and PVT (0.07%). Regression model results are shown in Table 1. Chest compression fraction was most strongly associated with ROSC and shockable rhythm. Depth was also associated with shockable rhythm. Leaning proportion and duty cycle were not associated with either outcome. Conclusions: In cases of non-shockable OHCA, CPR quality measures were associated with ROSC and transition to a shockable rhythm at the bout level.