Emergency department factors associated with survival after sudden cardiac arrest.

BACKGROUND: Sudden cardiac arrest (SCA) is a leading cause of death in the US. Recent innovations in post-arrest care have been demonstrated to increase survival. However, little is known about the impact of emergency department (ED) and hospital characteristics on survival to hospital admission and ultimate outcome.
OBJECTIVE: We sought to describe the incidence of SCA presenting to the ED and to identify ED and hospital characteristics associated with survival to hospital admission.
METHODS: We identified patients with diagnoses of atraumatic cardiac arrest or ventricular fibrillation (ICD-9 427.5 or 427.41) in the 2007 Nationwide Emergency Department Sample (NEDS), a nationally representative estimate of all ED admissions in the United States. We defined SCA as cardiac arrest in the out-of-hospital or ED settings. We used the NEDS sample design to generate nationally representative estimates of the incidence of SCA that presents to EDs. We performed unadjusted and adjusted analyses to examine the relation between patient, ED, and hospital characteristics and outcome using logistic regression. Our primary outcome was survival to hospital admission. Survival to hospital discharge was a secondary outcome. Data are presented as odds ratios (OR) with 95% confidence intervals (CI).
RESULTS: Of the 966 hospitals in the NEDS, 933 (96.6%) reported at least one SCA and were included in the analysis. We identified 38,593 cases of cardiac arrest representing an estimated 174,982 cases nationally. Overall ED SCA survival to hospital admission was 26.2% and survival to discharge was 15.7%. Greater survival to admission was seen in teaching hospitals (OR 1.3 95% CI 1.1-1.5, p=0.001), hospitals with ≥20,000 annual ED visits (OR 1.3 95% CI 1.1-1.6, p=0.003), and hospitals with percutaneous coronary intervention capability (OR 1.6 95% CI 1.4-1.8, p<0.001). Higher SCA volume (>40 annually) was associated with lower survival overall (OR 0.7 95% 0.6-0.9, p=0.010), but not when transferred patients were excluded from the analysis (OR 0.8 95% CI 0.6-1.1, p=0.116).
CONCLUSIONS: An estimated 175,000 cases of SCA present to or occur in US EDs each year. Percutaneous coronary intervention capability, ED volume, and teaching status were associated with higher survival to hospital admission. Emergency departments with higher annual SCA volume had lower survival rates, possibly because they transfer fewer patients. An improved understanding of the contribution of ED care to survival following SCA may be useful in advancing our understanding of how best to organize a system of care to ensure optimal outcomes for patients with SCA.