Abstract 11399: Time to Anti-Arrhythmic for Out-of-Hospital Cardiac Arrest

Introduction: Initial shockable rhythm is the strongest predictor of good outcomes for patients with out-of-hospital cardiac arrest (OHCA). While preclinical models have shown benefit of anti-arrhythmics, clinical trials have shown a very modest impact of anti-arrhythmic drugs, possibly related to real-life delays in drug administration. Little is known regarding the time to administration of anti-arrhythmic drugs or the association of time to drug and outcome. We utilized a national EMS registry to evaluate the time of drug administration and the association with outcomes. Methods: We evaluated the 2018 and 2019 NEMSIS dataset, including all non-traumatic, adult 911 EMS encounters for cardiac arrests with initial shockable rhythm. We then calculated the time from 911 call to administration of anti-arrhythmic. We excluded cases with time to administration less than 0 or greater than 120 minutes. Stratified by initial antiarrhythmic (amiodarone and lidocaine), we created a mixed-effect logistic regression model evaluating the association between every 5 minute increase in time to antiarrhythmic and ROSC. We modeled EMS agency as a random intercept and adjusted the analysis for age, sex, race, bystander witnessed arrest, location of arrest and EMS response time. We excluded EMS witnessed arrests and cases with missing ROSC data. Results: There were 449,630 adult, non-traumatic cardiac arrests identified with 55,142 patients (12.3%) having an initial shockable rhythm; 17,769 (32.2%) received amiodarone and 2,855 (5.2%) received lidocaine initially. The median time in minutes to initial dose of amiodarone was 20.4 with IQR (16-26.7). The median time in minutes to initial dose of lidocaine administration was 20.2 with IQR (15.7-27.0). Increasing time to initial antiarrhythmic was associated with decreased odds of ROSC for both amiodarone (aOR 0.9; 95% CI 0.9-0.94) and lidocaine (aOR 0.9; 95% CI 0.8-0.96). Conclusion: Time to administration of anti-arrhythmic medication varied, but most patients received the first does of anti-arrhythmic drug more than 20 minutes after the initial 911 call. Time to administration of antiarrhythmic was linked to ROSC.