The Impact of Hospital Bed Occupancy on Patient Flow and Emergency Department Access: A 25-Hospital Cohort Study

To evaluate the effect of hospital occupancy levels on inpatient and emergency department (ED) flow rates, ED length of stay (ED) and access block, and identify critical occupancy thresholds above which patient flow deteriorates.

Retrospective cohort study using routinely collected administrative data.

Twenty-five public hospitals in Queensland, Australia, over a 5.5-year period (1 April 2017 to 31 August 2022).

ED presentation and discharge rates, inpatient admission and discharge rates, hospital occupancy levels, length of stay, access block and 4-h rule compliance.

The analysis reveals a significant performance shift as hospital occupancy levels increase and identifies site-specific critical 'choke points' where patient flow deteriorates. Notably, as occupancy rises, we observed a growing divergence between ED presentations and discharge rates, and between inpatient admissions and discharges, indicating system congestion. Additionally, when assessing flow across the 25 hospitals, the data demonstrates that a 10% increase in bed occupancy rate correlates with a 0.32-h (19-min) extension in ED length of stay (or 33 min for patients admitted from the ED). Also, significant disparities in hospital operations were observed between weekends and weekdays, with weekday admissions and discharges up to three times higher than weekends, highlighting the increased operational pressure during the work week.

The investigation challenges the traditional 85% occupancy target, demonstrating that optimal occupancy levels vary by hospital. The study also underscores the strong correlation between hospital bed occupancy and ED access performance, with higher hospital occupancy correlating with longer ED stays and decreased adherence to performance indicators. As hospitals approach full capacity, the pressure on ED resources intensifies, resulting in longer wait times and delays in care.