Emergency department length of stay and outcomes of emergency department–based intensive care unit patients

Abstract

Objective: Emergency department (ED) boarding of patients who are critically ill is associated with poor outcomes. ED-based intensive care units (ED-ICUs) may mitigate the risks of ED boarding. We sought to analyze the impact of ED length of stay (LOS) before transfer to an ED-ICU on patient outcomes. Methods: We retrospectively analyzed adult ED patients managed in the ED-ICU at a US medical center. Bivariate and multivariable linear regressions tested ED LOS as a predictor of inpatient ICU and hospital LOS, and separate bivariate and multivariable logistic regressions tested ED LOS as a predictor of inpatient ICU admission, 48-hour mortality, and hospital mortality. Multivariable analyses’ covariates were age, sex, Charlson Comorbidity Index (CCI), Emergency Severity Index, and eSimplified Acute Physiology Score (eSAPS3). Results: We included 5859 ED visits with subsequent care in the ED-ICU. Median age, CCI, eSAPS3, ED LOS, and ED-ICU LOS were 62 years (interquartile range [IQR], 48–73 years), 5 (IQR, 2–8), 46 (IQR, 36–56), 3.6 hours (IQR, 2.5–5.3 hours), and 8.5 hours (IQR, 5.3–13.4 hours), respectively, and 46.3% were women. Bivariate analyses showed negative associations of ED LOS with hospital LOS (β = −3.4; 95% confidence interval [CI], −5.9 to −1.0), inpatient ICU admission (odds ratio [OR], 0.86, 95% CI, 0.84–0.88), 48-hour mortality (OR, 0.89; 95% CI, 0.82–0.98), and hospital mortality (OR, 0.89; 95% CI, 0.85–0.92), but no association with inpatient ICU LOS. Multivariable analyses showed a negative association of ED LOS with inpatient ICU admission (OR, 0.91; 95% CI, 0.88–0.93), but no associations with other outcomes. Conclusions: We observed no significant associations between ED LOS before ED-ICU transfer and worsened outcomes, suggesting an ED-ICU may mitigate the risks of ED boarding of patients who are critically ill.