Association of hypoxic ischemic brain injury on early CT after out of hospital cardiac arrest with neurologic outcome.

Aim: This study aimed to describe the prevalence of hypoxic-ischemic brain injury (HIBI) on head CT (HCT) obtained within two hours of return of spontaneous circulation (ROSC) care in the Emergency Department following out-of-hospital cardiac arrest (OHCA) and evaluate the association between early HIBI and neurologic outcome.

Methods: Retrospective single center observational study of post-OHCA patients between 2009 and 2017. Two cohorts were analyzed: those who underwent non-contrast HCT within two hours of ROSC and all others who survived to ICU admission. HIBI was defined as the presence of cerebral edema and/or abnormal gray-white matter differentiation in the HCT interpretation by a neuroradiologist. The primary outcomes were the prevalence of HIBI on early HCT and the magnitude of the association between HIBI and survival with good neurologic outcome using multivariable logistic regression.

Results: Following OHCA, 333 of 520 patients (64%) underwent HCT within two hours of ROSC and HIBI was present in 96 of 333 patients (29%). Of the early HCT cohort, those with HIBI had a significantly lower hospital survival (2%) and favorable neurologic outcome (1%). In those without HIBI on imaging, 88 of 237 patients (37%) had a favorable outcome. After adjustment for confounding variables, HIBI on early HCT was independently associated with a decreased likelihood of good neurologic outcome (aOR 0.015, 95% CI 0.002-0.12).

Conclusion: HIBI was present on 29% of HCTs obtained within 2 h of ROSC in the patients selected for early imaging by emergency physicians and was strongly and inversely associated with survival with a good neurologic outcome.