ED Overcrowding – Measure and Interventions

January 2009

Does BNP Augment Acute Decompensated CHF ED Management?

Search Strategy: For the first PICO question, PUBMED was searched using the term “emergency department overcrowding measurement” on December 18, 2008 you identify 21 citations including one pertinent study (PGY II). Using this single study, you identify another by selecting the “related articles” tab (122 citations – one pertinent).

For the second PICO question PUBMED is searched using clinical queries for therapy and the search term “emergency department overcrowding” yielding 4 citations, one of which is pertinent. The final article (PGY III) is obtained by reviewing the Annals of Emergency Medicine pre-publication website.

As the Director of Emergency Medicine at American Memorial Community Hospital, you are awakened at 2AM for the third night in a row by the charge nurse requesting permission to go on diversion. Your thirty-bed ED (without hallway beds) has 24-hour physician double-coverage. After the charge nurse informs you that technician and nursing levels are appropriate, she tells you that there are currently 28 patients in ED rooms with 12 awaiting inpatient bed assignments, including 2 ICU patients with one patient requiring constant one-on-one nursing care. Unfortunately, eight patients in the (15-seat) waiting room are still awaiting triage and will not have an ED room assigned for another several hours. As recommended by the Missouri Hospital Association, your hospital uses the “saturation index”:

Saturation Index [Number of ED beds + Number of Patients Waiting + Number of Pending EMS Arrivals + Number of Telemetry or Medical/Surgical Admissions + (Number of ICU Admits x 2) + (Number of one-on-one nursing care patients x 3) + 2 (if average wait time > 4 hours)] ÷ [ED bed capacity + Waiting Room Capacity]

For American Memorial tonight, the saturation index calculates as follows: [30 + 8 + 0(?) + 10 + (2 * 2) + (1 * 3) + 2] ÷ [30 + 15] = 57/45 = 1.27* *In order to justify ambulance diversions, an ED must have a saturation of >1.2. Alternative indicators of overcrowding include total ED volume over 90 patients, over 10 boarded patients, or over 3 trauma rooms double-booked.

Although you are not going to sleep again tonight, you contemplate a few pertinent questions in devising an answer to your anxious charge nurse. How does one decide if their ED should go on diversion? How do different institutions define “overcrowded”? Do any validated decision aids exist to quantify “overcrowded” in a standardized fashion? What interventions can help mitigate ED overcrowding?

PICO Question #1

Population: Emergency Departments

Intervention: Application of over-crowding indices

Comparison: Raw ED volumes

Outcome: Prognostic accuracy for over-crowding related outcomes (increased error rates, ED length of stay, staff burnout), reliability, physician/patient acceptability, external validity.

PICO Question #2

Population: Emergency Departments

Intervention: Operational Improvement Interventions to Reduce ED Overcrowding and/or Overcrowding Related Sequelae

Comparison: Routine ED operations

Outcome: Over-crowding related outcomes (error rates, ED length of stay, staff burnout), physician/patient acceptability, external validity.


First years: Development and validation of a new index to measure emergency department crowding, Acad Emerg Med 2003; 10: 938-942. (http://pmid.us/12957975)

Second years: Measuring and forecasting emergency department crowding in real time. Ann Emerg Med 2007; 49: 747-755. (http://pmid.us/17391809)

Third years: Adding more beds to the emergency department or reducing admitted patient boarding times: Which has a more significant influence on emergency department congestion? Ann Emerg Med 2009 in press (http://pmid.us/18783852)

Fourth years: Impact of a triage liaison physician on emergency department overcrowding and throughput: a randomized controlled trial, Acad Emerg Med 2007; 14: 702-708. (http://pmid.us/17656607)


Article 1: Development and Validation of a New Index to Measure Emergency Department Crowding, Acad Emerg Med 2003;10:938-942

Article 2: Measuring and Forecasting Emergency Department Crowding in Real Time, Annals EM 2007; 49: 747-755

Article 3: Adding More Beds to the Emergency Department or Reducing Admitted Patient Boarding Times: Which Has a More Significant Influence on Emergency Department Congestion? Annals EM 2009

Article 4: Impact of a Triage Liaison Physician on Emergency Department Overcrowding and Throughput: A Randomized Controlled Trial, Acad EM 2007; 14: 702-708

Emergency Department Crowding: What Is It, Is It a Problem, & How Do We Fix It?

Bottom Line

The Succinct Answer

For measuring ED overcrowding occupancy level is superior to EDWIN, NEDOCS, and READI and equal to the Work Score in identifying the need for ambulance diversion now. When assessing the ability to predict ambulance diversion in the next 4-hours, occupancy level is superior to all four tools. However, if permitted three false-alarms per week, READI can provide over one-hour advanced notice of the need for ambulance diversion compared with the other tools. While each of these now validated tools may offer valuable, additions to the over-crowding research and administrative armamentarium, future investigations should evaluate the ability of each to efficiently trigger interventions to offset the sequelae of over-crowding: ambulance diversion, prolonged waiting times, patient dissatisfaction, increased error rates, and staff burnout.

For combating overcrowding, ED LOS can be reduced by decreasing admitted patient departure times, but not by increasing the number of ED beds. A triage physician can significantly and independently reduce ED LOS, particularly in the sickest subset. Before widespread acceptance of these findings occurs, future research should prospectively confirm these findings while controlling for myriad confounding variables (staffing level, patient acuity, consultant responsiveness, etc.)