Abstract 429: The Association Between Naloxone Administration and Outcomes for Out-of-Hospital Cardiac Arrest Due to Suspected Overdose

Abstract

Background: Opioid overdose is increasingly implicated in the development of out-of-hospital cardiac arrest (OHCA) and is a leading cause of death for adults 25 to 64 years old. Aim: Evaluate the association between naloxone use and outcomes after OHCA due to suspected overdose. Methods: This study was a secondary analysis of data collected in the Portland Cardiac Arrest Epidemiologic Registry, a database containing details of Emergency Medical Services (EMS)-treated cases of cardiac arrest around Portland, OR. Eligible patients had non-traumatic OHCA due to presumed overdose with naloxone (exposed) or without naloxone administration (control). We excluded patients with return of spontaneous circulation (ROSC) before the first dose of naloxone. The primary outcome was ROSC at emergency department (ED) arrival. Secondary outcomes included survival to admission; survival to hospital discharge; and cerebral perfusion category score ≤2 at discharge (functional survival). We performed multivariable logistic regressions adjusting for age, sex, arrest location, witness status, bystander interventions, initial EMS rhythm, time from 911 call to EMS arrival, and year of arrest. We separately assessed the subgroup with non-shockable initial rhythms. Results: Of 3,942 OHCA from 2018-2021, EMS documented an overdose etiology in 249. Of these, 236 (94.8%) had all variables and 18 were excluded for achieving ROSC prior to naloxone, resulting in 218 cases for analysis (171 receiving naloxone). Patients receiving naloxone had no difference in adjusted odds (aOR [95% CI]) of ROSC at ED arrival (1.43 [0.64-3.20]), survival to admission (1.87 [0.85-4.10]), survival to discharge (1.99 [0.39-10.30]) and functional survival (1.99 [0.34-11.55]). The subgroup with non-shockable rhythms showed higher odds of survival to admission (2.55 [1.09-5.92]) but not ROSC at ED arrival (1.60 [0.68-3.75]), survival to discharge (8.43 [0.84-84.20]), or good neurologic outcomes (7.26 [0.75-70.42]). Conclusions: For OHCA due to suspected overdose, those with initial non-shockable rhythms who received naloxone had higher adjusted odds of survival to admission than those who did not. Larger studies are necessary to evaluate the impact of naloxone on OHCA outcomes.