Interobserver Variability in the Recognition of Hypoxic–Ischemic Brain Injury on Computed Tomography Soon After Out-of-Hospital Cardiac Arrest

Background: Cerebral edema and loss of gray–white matter differentiation on head computed tomography (CT) after cardiac arrest generally portend a poor prognosis. The interobserver variability in physician recognition of hypoxic–ischemic brain injury (HIBI) on early CT after out-of-hospital cardiac arrest has not been studied. Methods: In this survey study, participating physicians and a neuroradiologist reviewed 20 randomly selected head CTs obtained within 2 h of out-of-hospital cardiac arrest and decided if HIBI was present. All participants were blinded to clinical details. Interobserver agreement on the presence of HIBI (primary outcome) and pairwise agreement between participants and the neuroradiologist (secondary outcome) were determined using multi- and dual-rater kappa statistics with 95% confidence intervals (CIs). Results: Agreement among physicians regarding the presence of HIBI on head CT was fair (kappa 0.34; 95% CI 0.19–0.49). Individual physician agreement with the neuroradiologist varied from poor to moderate (kappa 0.0–0.48), with 8 of 10 physicians having no more than fair agreement. Regarding the perceived severity of HIBI on head CT, physician agreement was moderate (ICC = 0.56; 95% CI 0.38–0.77). Conclusion: Physicians, including radiologists, demonstrated substantial interobserver variability when identifying HIBI on head CT soon after out-of-hospital cardiac arrest.