The impact of emergency department (ED) overcrowding on
in-patient length of stay, mortality and time critical conditions
August 2009
The following literature review was written in response to the call made by the
Working Group for Achieving Quality in Emergency Departments for New Zealand
evidence on the impact of ED overcrowding on in-patient length of stay, mortality,
time critical conditions and hospital systems. The impact of overcrowding on hospital
systems is broadly covered in the Ministry of Health’s companion literature review
“Solutions to ED Overcrowding,” in Section 2: Using master plans within hospitals
and Section 5: Hospital capacity planning / managing access block.
The literature search1 by the Ministry of Health’s ED Team in 2009 produced no NZ
studies of the impact of overcrowding on in-patient length of stay or mortality
although in September 2008, two NZ newspapers reported on the impact of
overcrowding on mortality (NZ Herald, 2008 and Otago Daily Times, 2008). There is
NZ evidence for the impact of ED overcrowding on people with fractured neck of
femur (NZGG, 2003), (Turner P, Cocks J, 1997). In the absence of a range of NZ
studies, it seems reasonable to presume that the survey of international findings that
follows will be relevant here2.
ED overcrowding and in-patient length of stay3
ED overcrowding has been associated with prolonged in-patient length of stay in a
number of studies.
Long ED length of stay has been linked to an increased in-patient length of stay
(Working Group, 2008). In Canberra, patients kept in the ED for longer than eight
hours had an average in-patient length of stay after leaving the ED of 4.9 days,
compared to an average in-patient length of stay of 4.1 days for other patients
(Richardson DB. 2001). In Ferntree Gully, Victoria, a more complex study found that
the average length of stay for in-patients ranged from 3.73 days for patients who
stayed in the ED less than four hours, to 7.2 days for patients in the ED more than 12
hours. The observed correlation between ED and in-patient lengths of stay held true
when results were adjusted for age, sex, and time of presentation to the ED (Liew D.
Liew D. Kennedy MP, 2003). A study of 1536 intensive care admissions in hospitals
across six mid-Atlantic states supports these findings (Working Group, 2008). In that
study, the researchers found that all levels of administrators, physicians and nurses
must take measures to determine what affects timeliness of interventions, because
timely interventions affected outcomes, access and quality of care (Clark K, Normile
LB, 2007).
1
The search methodology is included in the appendix to the companion paper on “Solutions to ED
Overcrowding”
2
The starting point for this survey was the Working Group’s report (working Group, 2008) p.13 on
Overcrowding and Related Problems Have Been Linked to Negative Clinical Outcomes
3
The companion paper focuses on ED length of stay, rather than in-patient length of stay
1
ED overcrowding and mortality
Two Australian studies link ED overcrowding with increased mortality.
1. In Perth, 62,495 ED admissions and death records were the subject of a
retrospective study that found that there is an association between hospital
and ED overcrowding and increased mortality. This association was made
explicit by the use of an Overcrowding Hazard Scale. The Scale was based
on both hospital occupancy and percentage of patients in the ED who were
waiting for an in-patient bed in Perth hospitals. The researchers found that
where hospital bed occupancy was above 90 percent and 10-19 percent of
ED beds contained patients waiting for an in-patient bed, or with a similar
combinations of factors giving high hazard score ratings, 2.3 additional deaths
would be seen per 1,000 new patients at day 30. Overcrowding in Perth
hospitals was estimated to cause 120 deaths amongst 53,025 tertiary hospital
presentations during 2003 (Sprivulis PC, Da Silva J-A, et al 2006).
2. In Canberra, in a study of 34,377 overcrowded and 32,231 not overcrowded
presentations, there was a higher mortality rate by triage status in a study of
10 days mortality and overcrowding. Presentation during high ED occupancy
was associated with approximately one third increased in-hospital mortality at
10 days, after controlling for seasonal, shift, and day of the week effects. The
magnitude of the effect is about 13 deaths per year (Richardson DB, 2006).
The Otago Daily Times and the NZ Herald reported on 8 September 2008 that
“A shortage of hospital beds is killing as many as the national road toll of about
400..…Emergency doctors are calling for a 15% increase in the number of beds to
help solve the problem, following research that indicates hundreds die every
year…..An international review of studies on EDs, done for the (Australasian College
for Emergency Medicine) finds that overcrowding and blocked access increase the
risk of death 10 days later by 34%.....The review …..calculates the excess death toll
in Australia is similar to the annual road toll of about 1500…..Dr Tim Parke, clinical
director of Auckland City Hospital’s adults’ emergency department, said yesterday the
number of deaths in New Zealand probably matched its road toll too.…..Overcrowded
emergency departments lead to worse outcomes because of factors like delays in
starting antibiotics for pneumonia, delayed heart-attack care and patients simply
being overlooked because they are on a trolley in a corridor” (NZ Herald, 2008 and
Otago Daily Times, 2008)4.
Time-critical conditions
ED overcrowding causes delays to treatment and this can be detrimental for patients
with certain time-critical conditions (Duke G. Green J, Briedis J, 2004). A relationship
between time to treatment and clinical outcomes has been demonstrated for patients
with:
 stroke (Tilley BC, Lyden PD, et al, 1997), (Wester P, Radberg J et al 1999)
 acute myocardial infarction (Maynard C, Weaver WD, 1995), (Heath SM, Bain
RJI, et al 2003) (Diercks DB, Roe MT, et al, 2007) (Chan PS, Krumholz HM,
2008)
 fractured neck of femur (NZGG, 2003), (Turner P, Cocks J, 1997)
 compound/open and long bone fractures (Stewart DGJr, Kay RM, Skaggs
DL, 2005)
 sepsis, pneumonia and meningitis (International Sepsis Collaborative)
4
Debate ensued in Parliament between Hons Tony Ryall and Jim Anderton on the overcrowding issue
(They Work For You, 2008).
2
 penetrating trauma and major head injury (Brain Trauma Foundation)
 pneumonia in blunt trauma (Carr BG, Kaye AJ, et al, 2007)
 critical illness (Chalfin DB, Trzeciak S, et al, 2007).
______________________________________________________________
References
Brain Trauma Foundation, URL:
http://www.braintrauma.org/site/DocServer/Copy_of_Surgical_Guidelines_article_2.p
df?docID=143. (Accessed April 2009. Login required)
Carr BG, Kaye AJ, Wiebe DJ, Gracias VH et al (2007) Emergency department length
of stay: a major risk factor for pneumonia in intubated blunt trauma patients J.Trauma
63:9
Chalfin DB, Trzeciak S, Likourezos A, Baumann BM et al (2007) Impact of delayed
transfer of critically ill patients from the emergency department to the intensive care
unit. Crit Care Med 35:1477
Chan PS, Krumholz HM, Nichol G, Nallamothy BK, Mancini M, Berg R, Peberdy MA,
Allen E, Braithwaite S, Gosbee J, Hunt E, Larkin GL, Mears G, Nadkarni V, Truitt T,
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Defibrilation after In-Hospital Cardiac Arrest, N Engl J Med 358:9
Clark K, Normile LB (2007) Patient Flow in the Emergency Department: Is
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Diercks DB, Roe MT, Chen AY, Peacock WF et al (2007) Prolonged emergency
department stays on non-ST-segment elevation myocardial infarction patients are
associated with worse adherence to the American College of Cardiology/American
Heart association guidelines for management and increased adverse events. Ann
Emerg Med 50: 489)
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Heath SM, Bain RJI, Andrews A, Chida S, Kitchen SI, Walters MI (2003) Nurse
initiated thrombolysis in the accident and emergency department: safe, accurate, and
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(accessed April 2009)
Liew D, Liew D, Kennedy M P (2003) Emergency department length of stay
independently predicts excess inpatient length of stay MJA 179:524
Maynard C, Weaver WD (1995) Streamlining the triage system for acute myocardial
infarction, Cardiology Clinics 13(3):311
New Zealand Guidelines Group (2003) Acute management and immediate
rehabilitation after hip fracture amongst people aged 65 years and over
www.cebp.nl/media/m19.pdf
NZ Herald (8 Sept 2008)
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http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10531020
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http://www.odt.co.nz/news/national/21330/overcrowding-killing-patients
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Sprivulis PC, Da Silva J-A, Jacobs IG, Frazer ARL, Jelinek GA (2006) The
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via Western Australian emergency departments MJA 184 (5): 208
http://www.mja.com.au/public/issues/184_05_060306/spr10395_fm.html (accessed
April 2009)
Stewart DG Jr, Kay RM, Skaggs DL (2005) Open Fractures In Children – Principles
of Evaluation and Management Journal of Bone and Joint Surgery 87-A:12.
They work for you (2008)
http://theyworkforyou.co.nz/portfolios/health/2008/sep/10/emergency_departments
Tilley BC, Lyden PD, Brott TG, Lu M, Levine SR, Welch KMA (1997) Total Quality
Improvement Method for Reduction of Delays Between Emergency Department
Admission and Treatment of Acute Ischemic Stroke, Arch Neurol 54:1466
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of femur (DRG 210/211): prospective outcome study Australian and New Zealand
Journal of Surgery 67:126
Wester P, Radberg J, Lundgren B, Peltonen M (1999) Factors Associated With
Delayed Admission to Hospital and In-Hospital Delays in Acute Stroke and TIA,
Stroke 30:40
Working Group for Achieving Quality in Emergency Departments (2008)
Recommendations to Improve quality and the Measurement of Quality in New
Zealand Emergency Departments Wellington: Ministry of Health
http://www.moh.govt.nz
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