Measures of Emergency Department Crowding, a Systematic Review. How to Make Sense of a Long List

Abstract

Emergency department (ED) crowding, a common and serious phenomenon in many countries, lacks standardized definition and measurement methods. This systematic review critically analyzes the most commonly studied ED crowding measures. We followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. We searched PubMed/Medline Database for all studies published in English from January 1st, 1990, until December 1st, 2020. We used the National Institute of Health (NIH) Quality Assessment Tool to grade the included studies. The initial search yielded 2293 titles and abstracts, of whom we thoroughly reviewed 109 studies, then, after adding seven additional, included 90 in the final analysis. We excluded simple surveys, reviews, opinions, case reports, and letters to the editors. We included relevant papers published in English from 1990 to 2020. We did not grade any study as poor and graded 18 as fair and 72 as good. Most studies were conducted in the USA. The most studied crowding measures were the ED occupancy, the ED length of stay, and the ED volume. The most heterogeneous crowding measures were the boarding time and number of boarders. Except for the National ED Overcrowding Scale (NEDOCS) and the Emergency Department Work Index (EDWIN) scores, the studied measures are easy to calculate and communicate. Quality of care was the most studied outcome. The EDWIN and NEDOCS had no studies with the outcome mortality. The ED length of stay had no studies with the outcome perception of care. ED crowding was often associated with worse outcomes: higher mortality in 45% of the studies, worse quality of care in 75%, and a worse perception of care in 100%. The ED occupancy, ED volume, and ED length of stay are easy to measure, calculate and communicate, are homogenous in their definition, and were the most studied measures.

Overcrowding in Emergency Department: Causes, Consequences, and Solutions—A Narrative Review

“…It is important that the demand for assistance and the actual working capacity are balanced so that it can be ensured that the flow goes on properly, especially under emergency conditions [ 20 ]. Anything that compromises the flow of patients through the ED can lead to overcrowding [ 19 ]; if a resource (e.g., medical staff, consultant, diagnostic service, or bed slot) has a demand that exceeds its capacity, there will be a blockage in the system; therefore, the flow will be regular if available resources balance the demand in all the stages of the path [ 6 , 20 ].…”

“…Although many factors contribute to overcrowding, the latter depends essentially on three factors: the incoming volume of patients (input), the time to process and treat patients (throughput), and the volume of patients leaving the ED (output) [ 6 ].…”

“…An accurate measurement of crowding in the ED and an evidence-based understanding of its impact are essential prerequisites before attempting to find solutions [ 6 ]. Although there are various scores for estimating the different degrees of overcrowding, to date, there is still no gold standard for measuring this phenomenon [ 4 , 15 ].…”

Characteristics of First Nations patients who take their own leave from an inner‐city emergency department, 2016–2020

“…However, ‘length of wait time’ is universally accepted to be one of the most important factors associated with patients who leave unseen from the ED 14,16,17,20,24 . We used ‘Presentations in the previous hour’ as a marker of ‘ED Busyness’ because availability, but this measure has well‐documented limitations 13,30 . More robust ‘busyness’ markers such as ‘ED occupancy’ at the time of triage for each patient would have been preferable 30 .…”

FebriDx host-response point-of-care testing improves patient triage for coronavirus disease 2019 (COVID-19) in the emergency department

“…The influx of COVID-19 patients into EDs during the current omicron surge has exacerbated the long-standing problem of ED overcrowding. 5 Burnt-out healthcare workers and those who may be absent due to quarantine, isolation, or caring for a child whose school has been canceled lead to shortages of staff. 6,7 This shortage frequently results in insufficient capacity to open certain areas of the ED where isolation rooms might exist.…”