Ambulance diversion and its use as an ED
overcrowding mitigation strategy: Does it
work? A scoping review

Ambulance diversion and its use as an ED
overcrowding mitigation strategy: Does it
work? A scoping review

Emergency department (ED) overcrowding is a worldwide issue with significant negative consequences,

Abstract
Objective Emergency department (ED) overcrowding is a worldwide issue with significant negative consequences,
including increased patient mortality. Ambulance diversion (AD) is sometimes used as an intervention to momentarily
relieve overcrowded EDs, however, jury is still out about the negative consequences both for emergency medical
services (EMS) who are required to divert to an alternative destination, and for patients whose care is delayed.
Additionally, there is no operational guidance to best operationalize AD. The objective of this scoping review was to
collate and organize the peer-reviewed published literature on the effects of both diversion and diversion aversion
measures, on emergency medical services (EMS) and patient outcomes.
Method A systematic, comprehensive search was conducted in various databases to identify relevant studies.
Medline, Embase, CINAHL, Psychinfo, Cochrane and ClinicalTrials.gov databases were searched. Online ACEP and
NAEMSP portals were also searched. Included studies discussed AD in the setting of ED overcrowding that reported
either EMS or patient outcomes. The effects of interventions implemented to reduce AD were also reported. Two
independent reviewers screened the articles and consensus was reached when disagreements arose.
Results Out of 10,061 identified records, 95 papers meeting the inclusion criteria contributed to the results. 51 were
observational, 16 simulation, 15 interventional, 10 descriptive, 2 systematic reviews and 1 mixed method. 12 articles
reported negative EMS outcomes compared to only 2 neutral or positive EMS outcomes. 19 articles reported negative
patient outcomes, whereas 9 reported neutral or positive outcomes. 34 articles reporting on intervention attempts to
reduce diversion found overall positive results with diversion aversion. Only 7 articles studied the qualitative effects of
diversion.
Conclusion There is no conclusive evidence on the effects of AD on EMS and patient outcomes. 31 articles reported
negative EMS or patient outcomes with 11 articles reporting neutral or positive outcomes. Measures to reduce or avoid
diversion, however, showed overall positive trend in the results when diversion was averted. More research to ascertain
accurate effects with standardised criteria for outcomes is required. Qualitative outcomes were also not well reported and
further research should be conducted to determine the psychological impact on both staff and patients.

Jin Han Malcolm Ong1*, Bernard J. W. Lim2

, Muhammad Ariffin B. M. Zahrin3

, Isaac J. S. Yong4

, Luke L. L. Tan4
, Ren Hao

Desmond Mao1

, Marcus E. H. Ong5

and Fahad Javaid Siddiqui6

2025

Peri Irawan

pdf

english

text