Emergency department (ED) throughput efficiency is largely dependent on staffing and process, and many operational interventions to increase throughput have been described.

We systematically searched Medline, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials to find studies describing the impact of throughput strategies on ED length of stay and left without being seen rates. Two independent reviewers screened studies, evaluated quality and risk of bias, and stratified eligible studies by intervention type. We assessed statistical heterogeneity using the chi-squared statistic and the I-squared (I2) statistic, and pooled results where appropriate. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed.

Ninety-four (94) studies met inclusion criteria (Cohen's k = 0.7). Most were observational, five were determined to be low quality (Cohen's k = 0.6), and almost all reported modest reductions in length of stay and left without being seen rates, although there was substantial variability within and between intervention types. Fast track and patient streaming interventions showed the most consistent reduction in length of stay and left without being seenrates. Shifting high-level providers to triage appears effective and generally cost neutral. Evidence for enhanced testing strategies and alternative staffing models was less compelling.

Introducing a fast track and optimizing processes for important case-mix groups will likely enhance throughput efficiency. Expediting diagnostic and treatment decisions by shifting physician-patient contact to the earliest possible process point (e.g., triage) is an effective cost-neutral strategy to increase flow. Focusing ED staff on operational improvement is likely to improve performance, regardless of the intervention type.