UMEM Educational Pearls

Category: Quality Assurance/Quality Improvement

Title: Does Crowding Negatively Impact Low and Moderate Acuity Patients?

Keywords: Emergency Department Boarding, Emergency Department Crowding (PubMed Search)

Posted: 6/3/2023 by Brent King, MD
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The authors of this study retrospectively compared the 10-day mortality rates of patients who were triaged to levels 3-5 on the Scandinavian Rapid Emergency Triage and Treatment System (RETTS) during times of ED crowding (as measured by length of stay and percentage bed occupancy) with those who came to the ED at other times.


Patients were divided into four quartiles, corresponding with 2-hour length of stay blocks with quartile one having a length of stay of 2 or fewer hours and quartile four having a length of greater than 8 hours


Results: 705,076 patients were seen in one of two EDs from 2009 to 2016. The 10-day mortality rate was 0.09% (n = 623). The authors found an increased 10-day mortality for patients in quartile four as compared to those in quartile one “(adjusted odds ratio 5.86; 95% confidence interval [CI] 2.15 to 15.94)”  This was also true for times when the ED occupancy ratio was greater than one (more than one patient in the ED per available bed). “Adjusted odds ratios for ED occupancy ratio quartiles 2, 3, and 4 versus quartile 1 were 1.48 (95% CI 1.14 to 1.92), 1.63 (95% CI 1.24 to 2.14), and 1.53 (95% CI 1.15 to 2.03), respectively”


Older patients and those with co-morbidities were at greatest risk but lower-acuity patients in all age and morbidity classes had an increased risk of death within 10 days if they came to the ED when it was crowded.



The RETTS Triage System as Described by the Authors:


A “ 5-level triage scale descending from red (1) to blue (5), in which red represents the most urgent level. RETTS is based on one main principle: whether the patient is assessed as unstable or stable during triage. Unstable patients are experiencing potentially life-threatening conditions and are allocated to 1 of the 2 highest triage levels (1 to 2), whereas stable patients are allocated to 1 of the 3 lowest triage levels (3 to 5). Stable patients need medical attention but are considered able to wait because they are not at any obvious medical risk. RETTS uses a combination of vital signs and 59 chief complaint algorithms to allocate the triage level. The vital signs have cutoff levels for each triage level, and the chief complaint algorithms are known as emergency symptoms and signs for emergency care. Each emergency symptom and sign includes one or more chief complaints and is classified according to the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, 2007 (ICD-10), and a logistic process is attached to each algorithm”


The authors state that the RETTS system cannot be directly compared to the ESI system used in much of the US but they believe that RETTS levels 3-5 roughly correspond to levels 4 and 5 in the Canadian Triage and Acuity Scale.


Berg LM, Ehrenberg A, Florin J, et al. Associations Between Crowding and Ten-Day Mortality Among Patients Allocated Lower Triage Acuity Levels Without Need of Acute Hospital Care on Departure From the Emergency Department Ann Emerg Med. 2019;74:345-356.