Emergency Department Length of Stay for Critical Care Admissions. A Population-based Study.

RATIONALE: Hospital emergency department (ED) strain is common in North America. Excessive strain may result in prolonged ED length of stay and may lead to worse outcomes for patients admitted to intensive care units (ICUs).

OBJECTIVES: To describe patient, ED, and hospital characteristics associated with prolonged ED length of stay for adult patients admitted from EDs to ICUs.

METHODS: We conducted a population-based cohort study in the Province of Ontario, Canada, including patients admitted to an adult ICU from an ED and excluding only interhospital transfers and scheduled visits. Using regression modeling, we examined associations between patient- and hospital-level characteristics and two ED performance measures: length of stay in the ED of more than 6 hours and 90-day mortality.

MEASUREMENTS AND MAIN RESULTS: From April 2007 to March 2012, 261,274 adults presented to 118 EDs in Ontario, generating 314,836 ICU admissions. This activity represented 4.1% of all adult ED visits (incidence, 1,374 ICU admissions/100,000 ED visits). Median (interquartile range) ED length of stay was 7 (4-13) hours. Less than half (41.4%; 95% confidence interval [CI], 41.2-41.5) of these patients had an ED length of stay of 6 hours or less, whereas 10.5% (95% CI, 10.4-10.6) stayed 24 hours or longer. Hospital characteristics associated with ED length of stay more than 6 hours included shift-level ED crowding (mean length of stay of patients of similar acuity registering during same 8 h epoch) (odds ratio [OR], 1.19/h; 95% CI, 1.19-1.19), ED annual visit volume (OR, 1.01/1,000 patients; 95% CI, 1.01-1.01), time of ED presentation (00:00-07:59) (OR, 1.41; 95% CI, 1.38-1.45), and ICU functioning at greater than 20% above the average annual census (OR, 1.10; 95% CI, 1.08-1.12). ED length of stay more than 6 hours was not associated with 90-day mortality after adjustment for selected confounders (OR, 0.99; 95% CI, 0.97-1.02).

CONCLUSIONS: In this population-based study, less than half of adult ED patients were admitted to an ICU 6 hours or less after arrival to an ED, an internationally recognized performance indicator for ED care quality. ED and ICU strain generated by time-varying demand on capacity was an important determinant of ED length of stay. However, prolonged length of stay in an ED did not measurably reduce 90-day mortality.