Spring 2015
ETM 568
Callier, Demers, Drabek, & Hutchison
Carter, E. J., Pouch, S. M., & Larson, E. L. (2014). The relationship between
emergency department crowding and patient outcomes: a systematic
review. Journal of Nursing Scholarship, 46(2), 106-115.
“From 1999 to 2009 the number of visit to the emergency
department (ED) increased by 32% nationwide, from 102.8 to
136.1 million” (p.1).
During same time period…
 ED visits that resulted in hospitalizations increased from 13.2
to 17.1 millions
 ED visits that resulted in intensive care unit admission
increased from 1.1 to 2.2 million
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Insufficient inpatient hospital capacity results in extended
patient stay
Studies suggest that ED crowding is an issue on an
international scale
The relationship between ED crowding and care processes and
quality have been examined
The relationship between ED crowding and patient outcomes
had not previously been examined prior to this study
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
Through a research librarian at Columbia University Medical
Center, searched
◦ OVID Medline
◦ OVID Medline In-Process
◦ Other non-indexed citations search engines
for studies published between January 2002 and July 2012 using
keywords
 Also searched tables of contents of journals:
Emergency Medicine Journal, Emergency Medicine, Journal of
Emergency Nursing, Annals of Emergency Medicine, European
Journal of Emergency Medicine, and Academic Emergency Medicine
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1 researcher screened titles and abstracts
3 researchers independently reviewed remaining studies
4 researchers collectively discussed relevance of each article’s
inclusion in study
Studies that measured proxy of ED crowding were included
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(Carter, Pouch & Larson, p. 108)
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Adopted quality of observation studies’ assessment tool
developed by Agency for Healthcare Research and Quality
(AHRQ)
Evaluated whether study authors addressed following
domains:
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Study question population
Comparability of subjects
Exposure or intervention measurement
Outcome measurement
Statistical analysis
Results
Discussion
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
A total of 196 articles titles and abstracts were screened
◦ 180 of these did not meet inclusion criteria
◦ 5 did not meet exclusion criteria
◦ Leaving 11 articles for review
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Emergency Department Characteristics
Relationship Between Emergency Department Crowding and
Patient Outcomes
Quality Appraisal
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Majority of the research examined Emergency Departments that
were located in urban areas or part of tertiary care facilities
One study was conducted in a community teaching hospital
One study had an ED annual visit rate of 35,000, the other ten had
upwards of 45,000
Three studies were conducted outside of the U.S. in Korea, Canada,
and Australia
◦ These three included children analyses
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Study periods ranged from 18 days to 7 years
Two studies were prospective, and the rest were retrospective or
had retrospective components
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Negatives
◦ Many studies lacked study questions and population domain information
 Only one study included a sample size justification or power calculation
 Four studies did not provide characteristics of their sample
◦ One study assessed ED crowding as perception of ED providers
◦ One surveys questions appeared leading which likely influenced responses
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Positives
◦ A majority of the studies fully addressed:
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Exposure measure
Outcome Measure
Statistical Analysis
Result Domains
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Findings
◦ “Several studies have detailed the relationship between ED crowding
and patient outcomes. Notably, studies found that ED crowding is
associated with higher rates of inpatient mortality among those
admitted to the hospital from the ED and discharged from the ED to
home. Studies also consistently found that ED crowding is associated
with higher rates of individuals leaving the ED without being seen.
Given the significance and magnitude of ED crowding, policies are
needed to address this major patient safety concern”
Significance
◦ This study offers conclusions about the safety and efficacy of the
American medical system based on somewhat sparse evidence.
The inclusion of various articles in the present study was determined
through “group discussion and consensus”. This method may be
reason to question the validity of the article selection.
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 “Only in the three international studies did authors primarily seek to detect and
find a relationship between ED crowding and patient mortality “
 “In a retrospective cohort, Cha and colleagues (2011) reported that 30-day
mortality was significantly greater among pediatric patients exposed to ED
crowding, versus pediatric patients not exposed to crowding (hazard ratio
[HR] 1.26; 95% confidence interval [CI] 1.02–1.59).” (Korea)
 “In a retrospective stratified cohort study, Richardson (2006) reported that
the risk of 10-day inpatient mortality for patients admitted to the hospital via
the ED during crowding periods was 34% higher (relative risk [RR] 1.34; 95%
CI 1.04–1.72) “ (Australia)
 “Guttman et al. (2011) found that the risk for 7-day death among those
discharged from the ED was greater among those who visited the ED during
shifts with mean patient length of stay ≥ 6 hr than among those who
presented to the ED during shifts with mean length of stay <1 hr (odds ratio
[OR] 1.79; 95% CI 1.24–2.59).” (Canada)
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 Study form the University of Pennsylvania
 “Pines and colleagues (2009) performed a retrospective cohort study to
examine the relationship between ED crowding and adverse cardiovascular
outcomes (e.g., dysrhythmias, heart failure, cardiac arrest, etc.) among ED
patients admitted to the hospital with acute coronary syndrome (ACS)related chest pain and non-ACS-related chest pain. Authors found a positive
relationship between adverse cardiovascular outcomes and several ED
crowding measures.”
 This study could not determine the cause of the adverse outcomes.

Future Work
◦ Investigate the impact of the affordable care act on ED crowding
 Evidence from the Massachusetts health care system indicated that similar
health reform laws have failed to reduce ED utilization.
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◦ This article provides evidence that estimates of ED crowding are
significantly associated with several negative outcomes. Such as
patient LWBS, morbidity, and mortality.
◦ The article did not offer any rationale for the observed results from
crowded emergency departments
◦ The (pines et al 2009) study presented on the previous page
hypothesized that their observed results were based on less time
for communication between the care provider and the patient
 This hypothesis was based on evidence that the majority of the adverse
health outcomes occurred more than 24 hours after ED admission.
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