Neurological Injury in Comatose Patients Following Substance-Use-Related Out-of-Hospital Cardiac Arrest: A Retrospective Cohort Study in a Safety Net Hospital.

Background: Substance-use-related cardiac arrest (SURCA) is a public health crisis, contributing to high mortality and severe neurological disability, particularly affecting young adults. This study aims to characterize the demographic and multimodal neurological prognostication features of patients with SURCA.

Methods: This retrospective study included patients with out-of-hospital cardiac arrest who presented to an urban academic safety net hospital between July 2016 and April 2022 and were comatose on admission. Patients with SURCA were identified through toxicology screening. Data on demographics, cardiac arrest characteristics, and multimodal neurological prognostication were collected. Poor neurological outcome was defined as a Cerebral Performance Category score of 3-5 at hospital discharge. Logistic regression was used to identify factors associated with poor neurological outcomes.

Results: Among 253 patients, 99 (39%) were classified as having SURCA, with 67 testing positive for stimulants and 56 testing positive for opioids. Patients with SURCA were younger (49 vs. 66 years, p < 0.001), less likely to have a witnessed cardiac arrest (56% vs. 71%, p = 0.01), and more likely to present with nonshockable rhythms (88% vs. 73%, p < 0.001). Electroencephalogram (EEG) monitoring in the SURCA cohort revealed a higher incidence of generalized periodic discharges (54% vs. 35%, p = 0.02) and electrographic seizures (28% vs. 13%, p = 0.02). Outcomes were similar between SURCA and non-SURCA groups; 86% of patients with SURCA had poor neurological outcomes, with 67% not surviving to discharge, compared to 88% and 69% of patients with non-SURCA, respectively. Nonshockable rhythms and older age were associated with poor neurological outcomes, but SURCA was not.

Conclusions: SURCA is common and is frequently associated with poor neurological outcomes despite affecting younger patients. A higher incidence of seizures and generalized periodic discharges on EEG was observed with SURCA; therefore, validation of this finding in larger multicenter cohorts is warranted. Public health interventions to improve bystander resuscitation education in populations at risk for SURCA may improve outcomes in this vulnerable population.