Measures of Crowding in the Emergency Department: A Systematic Review

Abstract

Objectives: Despite consensus regarding the conceptual foundation of crowding, and increasing research on factors and outcomes associated with crowding, there is no criterion standard measure of crowding. The objective was to conduct a systematic review of crowding measures and compare them in conceptual foundation and validity.Methods: This was a systematic, comprehensive review of four medical and health care citation databases to identify studies related to crowding in the emergency department (ED). Publications that ''describe the theory, development, implementation, evaluation, or any other aspect of a 'crowding measurement ⁄ definition' instrument (qualitative or quantitative)'' were included. A ''measurement ⁄ definition'' instrument is anything that assigns a value to the phenomenon of crowding in the ED. Data collected from papers meeting inclusion criteria were: study design, objective, crowding measure, and evidence of validity. All measures were categorized into five measure types (clinician opinion, input factors, throughput factors, output factors, and multidimensional scales). All measures were then indexed to six validation criteria (clinician opinion, ambulance diversion, left without being seen (LWBS), times to care, forecasting or predictions of future crowding, and other).Results: There were 2,660 papers identified by databases; 46 of these papers met inclusion criteria, were original research studies, and were abstracted by reviewers. A total of 71 unique crowding measures were identified. The least commonly used type of crowding measure was clinician opinion, and the most commonly used were numerical counts (number or percentage) of patients and process times associated with patient care. Many measures had moderate to good correlation with validation criteria.Conclusions: Time intervals and patient counts are emerging as the most promising tools for measuring flow and nonflow (i.e., crowding), respectively. Standardized definitions of time intervals (flow) and numerical counts (nonflow) will assist with validation of these metrics across multiple sites and clarify which options emerge as the metrics of choice in this ''crowded'' field of measures.

Wait times in the emergency department for patients with mental illness

“…6,14 Perhaps surprisingly, as crowding increased, the delays experienced by patients with mental illness were actually lesser than the delays experienced by other patients; this is in contrast to concerns that these patients are disproportionately affected by crowding in the emergency department. 8,10 For time to physician assessment, this effect may be partly explained by the presence of dedicated psychiatric teams in some emergency departments. In Ontario, these teams are available in many emergency departments that see a high volume of psychiatric patients (academic centres and some large community hospitals); these are the same centres that experience crowding.…”

“…Length of stay is a good proxy for crowding 8,9 and is commonly used in crowding research. [10][11][12] This variable is calculated by dividing the day into three 8-hour periods and determining the median length-ofstay of all patients who were present in the emergency department during that period.…”

Physician-Rated Utility of Procedure Videos for Teaching Procedures in the Emergency Department, Overall and during Emergency Department Crowding

“…The first was with a dichotomous measure: physician perception of crowding during the shift worked. EP perception of crowding has been shown to have good correlation with many standard crowding measures [14]. This was measured as either "yes" or "no", and if "yes", whether it was such that the EP was very busy managing the emergency department (emergency department crowded), or such that there were no beds to see patients in, and the EP had more time available (emergency department not crowded, in terms of teaching availability).…”

Expanding emergency department capacity: a multisite study

“…Finally, research examining structures, processes and other outcomes not described within our study (e.g. costs, time to triage, re-presentation, readmission rates and other crowding measures noted by Hwang et al 46 and Liu et al 47 ) can be useful in providing further insight into the care quality and outcomes of this change in service and to this patient group. Further research accounting for these limitations is warranted.…”