Associations between early CT head findings and clinical characteristics following out-of-hospital cardiac arrest

Abstract

Abstract Background/Objective Cardiac arrest is a leading cause of death and disability in the United States. Current consensus guidelines recommend obtaining a non-contrast CT head as part of standard post-arrest care. We aimed to correlate early CT findings of hypoxic-ischemic encephalopathy (HIE) with specific arrest characteristics in a pragmatic and generalizable fashion. Methods This is a retrospective multi-center cohort of patients with out-of-hospital cardiac arrest (OHCA) who underwent whole-body imaging within 6 hours of hospital arrival. Head CT reports were systematically analyzed with an emphasis on findings suggestive of HIE, including cerebral edema, sulcal effacement, and blurred grey-white junction. The primary exposure was the duration of cardiac arrest. Secondary exposures included bystander cardiopulmonary resuscitation (CPR), initial cardiac rhythm, and cause of arrest. The primary outcome was the presence of CT findings consistent with HIE. Results A total of 227 patients (average age 55 years, 32% female, 65% White, 56% witnessed arrest, 31% shockable rhythm) were included in the final analysis. CT findings of HIE were seen in 47 (48.3%) patients. Univariable analysis showed an association between HIE and CPR duration (OR 1.05, 95% CI 1.02–1.09, p = 0.002), age (OR 0.97, 95% CI 0.95–0.99, p = 0.004), and shockable rhythm (OR 0.34, 95% CI 0.14–0.81, p = 0.015). Multivariate analysis demonstrated a correlation between CT findings of HIE and age under 55 (OR 2.6, 95% CI 1.2 -5 .6, p = 0.02) and CPR duration (OR 1.1, 95% CI 1.02–1.1, p < 0.01) but not with the initial rhythm. Conclusion Signs of HIE are commonly seen on initial CT head within 6 hours of OHCA, occurring in approximately half of patients, and associated with CPR duration. These findings may identify pathophysiological changes in the early stages after OHCA.