The association between emergency department crowding and adverse cardiovascular outcomes in patients with chest pain.

OBJECTIVES: While emergency department (ED) crowding is a worldwide problem, few studies have demonstrated associations between crowding and outcomes. The authors examined whether ED crowding was associated with adverse cardiovascular outcomes in patients with chest pain syndromes (chest pain or related complaints of possible cardiac origin).

METHODS: A retrospective analysis was performed for patients >or=30 years of age with chest pain syndrome admitted to a tertiary care academic hospital from 1999 through 2006. The authors compared rates of inpatient adverse outcomes from ED triage to hospital discharge, defined as delayed acute myocardial infarction (AMI), heart failure, hypotension, dysrhythmias, and cardiac arrest, which occurred after ED arrival using five separate crowding measures.

RESULTS: Among 4,574 patients, 251 (4%) patients developed adverse outcomes after ED arrival; 803 (18%) had documented acute coronary syndrome (ACS), and of those, 273 (34%) had AMI. Compared to less crowded times, ACS patients experienced more adverse outcomes at the highest waiting room census (odds ratio [OR] = 3.7, 95% confidence interval [CI] = 1.3 to 11.0) and patient-hours (OR = 5.2, 95% CI = 2.0 to 13.6) and trended toward more adverse outcomes during time of high ED occupancy (OR = 3.1, 95% CI = 1.0 to 9.3). Adverse outcomes were not significantly more frequent during times with the highest number of admitted patients (OR = 1.6, 95% CI = 0.6 to 4.1) or the highest trailing mean length of stay (LOS) for admitted patients transferred to inpatient beds within 6 hours (OR = 1.5, 95% CI = 0.5 to 4.0). Patients with non-ACS chest pain experienced more adverse outcomes during the highest waiting room census (OR = 3.5, 95% CI = 1.4 to 8.4) and patient-hours (OR = 4.3, 95% CI = 2.6 to 7.3), but not occupancy (OR = 1.8, 95% CI = 0.9 to 3.3), number of admitted patients (OR = 0.6, 95% CI 0.4 to 1.1), or trailing LOS for admitted patients (OR = 1.2, 95% CI = 0.6 to 2.0).

CONCLUSIONS: There was an association between some measures of ED crowding and a higher risk of adverse cardiovascular outcomes in patients with both ACS-related and non-ACS-related chest pain syndrome.