Patients with a primary ICU admission diagnosis of cardiac arrest were identified in the 2002–2005 Acute Physiology and Chronic Health Evaluation (APACHE) IV dataset, a multicenter clinical registry of ICU patients.
We identified 4674 patients from 39 hospitals. The median number of annual patients was 33 per hospital (range: 12–116). Mean APACHE score was 94 (±38), and overall mortality was 56.8 % . Age, severity of illness (acute physiology score), and admission Glasgow Coma Scale were all associated with increased mortality (p < 0.001). There was no survival difference for patients admitted from the emergency department vs. the inpatient floor. Among institutions, unadjusted in-hospital mortality ranged from 41 % to 81 % . After adjusting for age and severity of illness, institutional mortality ranged from 46 % to 68 % . Patients treated at higher volume centers were significantly less likely to die in the hospital.
We demonstrate hospital-level variation in severity adjusted mortality among patients admitted to the ICU after cardiac arrest. We identify a volume–outcome relationship showing lower mortality among patients admitted to ICUs that treat a high volume of post-cardiac arrest patients. Prospective studies should identify hospital-level and patient care factors that contribute to post-cardiac arrest survival.