Emergency Department Crowding in the Modern Era: A Systematic Review (2018-2025)

Document Type

Journal Article

Publication Date

1-14-2026

Journal

Clinical and experimental emergency medicine

DOI

10.15441/ceem.25.172

Keywords

COVID-19; Emergency department; Emergency department crowding; Emergency department length of stay EDLOS; Length of stay

Abstract

OBJECTIVE: This study systematically reviews the causes, effects, and potential solutions to emergency department (ED) crowding, with emphasis on challenges amplified by the COVID-19 pandemic. METHODS: Following PRISMA guidelines, we searched MEDLINE, CINAHL, and Web of Science for peer-reviewed studies published from January 1, 2018, to January 31, 2025, that investigated ED crowding. Studies were included if they evaluated crowding causes, consequences, or interventions, using metrics such as ED length of stay, boarding, or left without being seen. Four reviewers independently screened titles, abstracts, and full texts. Study quality was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) critical appraisal tools. This review was registered with PROSPERO (CRD420251117676). RESULTS: Of 23,408 studies identified, 226 met inclusion criteria. Most studies were retrospective (83%) and of low (62%) or acceptable (35%) quality. Crowding was primarily driven by input (high patient volumes, limited primary care access), throughput (staffing shortages, laboratory and imaging delays), and output (boarding, late discharges) factors. Adverse effects included increased mortality, treatment delays, prolonged inpatient stays, higher rates of patients leaving without being seen, and reduced patient satisfaction. Effective strategies included provider-in-triage, nurse-initiated orders, and split-flow models. Output-focused interventions, such as active bed management and early discharge protocols, required system wide coordination. The COVID-19 pandemic shifted patient volumes and led to innovative solutions such as drive-through clinics and repurposed spaces to alleviate surges. CONCLUSION: ED crowding is a persistent global issue with significant clinical and operational consequences. While promising interventions exist, high-quality evidence remains limited, underscoring the need for system-level and multifaceted solutions.

Department

Emergency Medicine

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