Etiology of nontraumatic out-of-hospital cardiac arrest with return of spontaneous circulation and predictive values of computed tomography findings for in-hospital mortality in affected patients.

Computed tomography (CT) scans are increasingly requested for nontraumatic out-of-hospital cardiac arrest (OHCA) patients with return of spontaneous circulation (ROSC). CT scan findings contribute to the diagnosis of cardiac arrest and patient management. The primary objective of this study is to determine the causes and frequencies of cardiac arrest in nontraumatic OHCA patients with ROSC, and the secondary objective is to determine the CT preferences of clinicians and the predictive values of CT findings for in-hospital mortality in these patients. The population of this retrospective single-center cohort study consisted of 863 nontraumatic OHCA patients brought to the emergency department of a tertiary hospital between January 1st, 2016, and December 31st, 2020. The study sample consisted of 258 nontraumatic OHCA patients with ROSC aged 18 years and older who underwent radiographic imaging within 24 hours after emergency department admission. Two emergency medicine specialists determined the causes of cardiac arrest based on all available data. Patients' radiological images were re-reported by a radiologist. CT findings associated with in-hospital mortality were determined. The median age of 258 patients included in the sample, 163 (63.2%) of whom were male, was 67 years (interquartile range: 17, min: 18-max: 94). Cardiac arrest occurred primarily due to cardiac causes (35.3%), followed by pulmonary causes (29.1%), while the cause could not be determined in 22.9% of the patients. The radiological imaging method most preferred by clinicians was cranial CT (n = 238, 92.2%), followed by thoracic CT (n = 236, 91.5%) and abdominal CT (n = 141, 54.7%). The in-hospital mortality rate was 88%. Several thoracic CT findings, including infiltration/consolidation (odds ratio: 6.74; 95% confidence interval [CI]: 1.35-33.56, P = .017), chronic lung pathologies (OR: 1.39; 95% CI: 0.44-4.8, P = .026), and chronic lung pathologies accompanied by pneumothorax (OR: 17.5; 95% CI: 1.7-178.4, P = .001) were significantly associated with in-hospital mortality. We found that cardiac causes were the most common causes of cardiac arrest in nontraumatic OHCA patients with ROSC. Additionally, clinicians most frequently requested cranial and thoracic CT for these patients. Of note, thoracic CT findings were significantly associated with in-hospital mortality.