Using Clinical Decision Units to Improve ED Efficiency

Executive Summary

Patients who seek emergency department (ED) treatment are often found not well enough for immediate discharge yet are also not sick enough to warrant full inpatient admission. These patients are increasingly treated as outpatients using observation services. Clinical Decision Units (CDU) provide a potential solution by allowing protocol-driven care for patients who require longer observation, but don’t require admission. This strategy can help patients go home safer and faster, while saving hospitals money. A clinical decision unit (CDU) is a designated section of the emergency department where patients are monitored by a staff team for 6-24 hours. Patients who require observation or testing are moved to a separate area where they are monitored and treated according to disease-specific protocols. Further information detailing the operation of a CDU can be found in each of the following sections of this article:

  • Principles of Care
  • Physical Design
  • Admission Criteria
  • Benefits & Drawbacks of CDUs


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Principles of Care

For a CDU to be successful, there is a need for a clear vision among staff in a system with tight structural organization, processes of delivery, and well-defined outcome measures to evaluate performance. The structural organization must include circumstances that require notification of the physican who is respphysicianfor the patient, and a maximum allowable length of stay in the unit.

Physical Design

CDUs work best when they are located in or near the ED to minimize travel costs and maintain infection control measures. Although amenities such as telephone and TV are not necessary, the area should be designed to maximize patient comfort during a 24-hour stay. All CDU patients should be kept in the same area to make it easier for staff to properly care for them.

Admission Criteria

ED staff may be tempted to use the CDU as a temporary place for “difficult-to-discharge” patients; this is not the original intention and may create long-term problems. The American College of Emergency Physicians (ACEP) recommends CDU observation for patients with the following conditions:

  • Chest pain
  • Asthma
  • Heart failure
  • Syncope
  • Arrhythmia
  • Transient ischemic attack
  • Deep vein thrombosis
  • Blood transfusion or other IV therapy


Benefits & Drawbacks of CDUs

The ideal CDU patient requires monitoring for less than 24 hours. Prior to the CDU phenomenon, an emergency room physician had to choose to keep the patient in an Emergency Department (ED) bed for observation or to request for the patient's admission to hospital. In the first case, a valuable ED bed would be out of commission for several hours; in the second case, hospital resources would be used on an expensive admission that may end up being only several hours long.

Hospitals with CDUs can expect the following benefits:1

  • Reduced number of admissions to hospital results in cost savings and better patient flow;
  • Decreased wait times and decreased length of stay for patients in the emergency room; and
  • Enhanced quality and patient safety through close observation and protocol-based treatment.


A recent study showed that patients in a CDU had a 25% shorter overall length of stay, resulting in estimated cost savings of $1 billion/year across the US.2 For these reasons, the ACEP has included CDUs as a Best Practice. In 2007, however, only 36 percent of US hospitals had a CDU.A recent Canadian study found only 4% of ED patients were admitted to CDU's noting that limited efficiencies were gained, however, small improvements were noted in ED LOS, decreased admission and readmission rates.7


Some drawbacks to CDUs have been noted, including tendency to discharge patient's close to the 24-hour mark, 'ownership' issues around who is most responsible for the patient, staffing challenges and reimbursement disincentives. 

Key Takeaways:

Clinical Decision Units can be an effective way to assess patients who require close monitoring over a short duration in order to determine next steps. CDUs are best suited for patients with specific needs, and require the use of evidence-based protocols in order to ensure that these spaces are being used appropriately. Organizational structures must be in place with clear lines of accountability for managing CDUs. Related articles: