Inter-hospital variability in post-cardiac arrest mortality

A growing body of evidence suggests that variability in post-cardiac arrest care contributes to differential outcomes of patients with initial return of spontaneous circulation after cardiac arrest. We examined hospital-level variation in mortality of patients admitted to United States intensive care units (ICUs) with a diagnosis of cardiac arrest.

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.