AIM: To explore the impact of spatial separation on ED patient flow and to identify specific clinical factors and flow process intervals (FPIs) influencing ED length of stay (EDLOS).

METHODS: This was a retrospective study of data extracted from patients' electronic medical records from January 1st to March 31st, 2022 conducted at the ED of a tertiary hospital in Kuala Lumpur, Malaysia. During this period, patients were separated into respiratory areas (RA) and non-respiratory areas (NRA) based on Centers for Disease Control and Prevention recommendations. The study obtained ethics approval from the institution's ethics board.

FINDINGS: A total of 1054 patients were included in the study, 275 allocated to RA and 779 to NRA. Patients in RA had a significantly longer median EDLOS compared with NRA (9 h 29 min vs 7 h 6 min, P < 0.001, d = 0.41). A lower proportion of patients in RA achieved an EDLOS ≤8 h compared to NRA (41.8% vs 58.3%, P < 0.001). Independent factors affecting EDLOS were: triage category; re-triaging; hypertension; performing biomedical imaging; medical, surgical, and critical care consultations; and disposition plan. Bottlenecks significantly prolonging EDLOS were decision-to-departure, ultrasound interval, and referral-to-consultation.