Authors' objectives:

The objective of the systematic review was to identify and characterize the measures and indicators that have been used to document emergency department (ED) overcrowding in the scientific literature. The objective of the Delphi study was to identify the level of consensus among a group of Canadian ED experts on the importance and relevance of measures to document ED overcrowding.

Authors' results and conclusions: From 486 potentially relevant studies, 169 studies were selected; 735 measures documenting ED overcrowding were identified (median number per study=3; interquartile range=2, 5). Operational definitions of ED overcrowding were infrequently reported (31%). Most measures focused on delays in the process of ED care (39.7%), overall volume of patients in the ED (11.6%), volume of patients waiting to receive care at different stages (8.8%), or the proportion of patients being seen at different stages while in the ED (7.6%). Measures such as ED access block (7%), ambulance diversion (7%), number of patients who left without being seen (5.5%), and ED length of stay (4.2%) were less commonly reported. When the measures were analyzed according to the input-throughput-output model of ED service pressures, throughput measures were the ones most commonly used (67.8%), followed by input and output measures (19.5% and 11.8% respectively). System measures were reported less often (0.8%). For the Delphi study, 32 participants (84% response rate) completed the questionnaire in the first round, and 33 participants (87% response rate) completed the second round. The most important measure identified was the percentage of the ED occupied by in-patients. The other top five measures, in order of importance, were total ED patients, total time in the ED, percentage of time ED is at or above capacity, and overall bed occupancy. The top 10 measures reported accord with measures that researchers in English-speaking countries outside North America have considered to be important for documenting ED overcrowding.

Authors' recommendations: The evidence reveals the limitations of research on measuring overcrowding in EDs. Many measures and indicators have been used, and there is little agreement on the development of standardized definitions and measures that take into account regional variations and differences between EDs. The multitude of measures and their variable definitions highlight the complexity of this issue. The inconsistent use of definitions, indicators, and measures of ED overcrowding has created a contradictory research base. This report describes a set of indicators that may be used to evaluate the problem of ED overcrowding, and thereby make it more consistently measurable across settings. Through the combination of a literature review and a Delphi study, 10 clinically important indicators were identified. The measures developed using consensus techniques have face validity, and those based on the rigorous collection of evidence possess content validity. These indicators should be tested for acceptability, feasibility, reliability, sensitivity to change, and validity to optimize their effectiveness for documenting ED overcrowding across Canada. Without a greater knowledge of the measurement properties of ED overcrowding indicators, study results will remain difficult to interpret, and consequently of limited value to policy makers, clinicians, and patients.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.cadth.ca/

Year Published: 2006

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Canada

Organisation Name: Canadian Agency for Drugs and Technologies in Health

Contact Address: 600-865 Carling Avenue, Ottawa, ON K1S 5S8 Canada. Tel: +1 613 226 2553; Fax: +1 613 226 5392;

Contact Name: requests@cadth.ca

Contact Email: requests@cadth.ca

Copyright: Canadian Agency for Drugs and Technologies in Health (CADTH)