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All EMS systems must be looked at as a continual "Chain of Survival" of which the telecommunicator is a vital link. As a primary point of contact with the public, the dispatcher provides a channel for communications between the caller reporting the emergency and the Emergency Medical Response Units.

The Emergency Medical Dispatch (EMD) program includes medically-approved emergency medical dispatch triage guidelines for telecommunicators, a comprehensive EMD training program, quality improvement measures and ongoing research. The Criteria Based Dispatch guidelines are an internationally-recognized innovative approach to emergency medical dispatching. These guidelines have been implemented in a number of jurisdictions in the United States, Sweden, Norway, and Israel and are available for use by other jurisdictions via a licensing agreement with the King County Emergency Medical Services Division. These EMD guidelines have resulted in a more effective and efficient use of emergency medical services resources, particularly paramedic (ALS) services in King County.

Criteria Based Dispatch (CBD) is based on the recognition that the level of care (ALS vs. BLS) needed by the patient and the urgency of patient care should be the determining factors in the level of response. Critical medical emergencies are those where paramedic intervention within minutes can be crucial to the patient's outcome. Non-critical emergencies are those in which paramedic intervention is not immediately needed and time is not a critical factor in treatment; therefore, a delay of several minutes would make no difference. In other words, we should not be sending a level of care the patient does not need and we should not be sending units Code Red using red lights and siren if time is not critical to patient care.

In 1989, King County EMS developed the Criteria Based Dispatch Guidelines, which were implemented in 1990. CBD Guidelines are based on:

  • the level of care required for a patient;
  • the urgency for the care to be given; and,
  • the specified medical criteria for determining the appropriate response.

The development process included an exhaustive analysis of our EMS dispatch system in King County and a review of other EMD protocols available at that time. Rather than buy existing EMD protocols, King County EMS chose to develop our own program. Not only does CBD provide guidelines to identify dispatch criteria for the appropriate response, but they also provide Pre-Arrival Instructions, of which the most important are those of CPR.

The Criteria Based Dispatch Guidelines differ from other approaches to guidelines or protocols for telecommunicators. The CBD Guidelines do not give telecommunicators required questions for use in interrogating the caller, with the exception of an All Callers Interrogation. Instead, the dispatcher uses symptom criteria, i.e. specific signs and symptoms or mechanism of injury to determine which level of response is appropriate. This allows critical medical conditions to receive an ALS response and less critical conditions to receive a BLS response.

Quality improvement

The system is monitored at three levels:

  • First, an in-house evaluation form is available for individual dispatchers, peer evaluation and supervisor evaluation.
  • Second, all dispatchers, EMTs, nurses and paramedics within the EMS system are encouraged to use a Suggestions/Comments/Kudos form (PDF) to provide feedback to communication centers and to the King County EMS Division. Specific problem areas may be reviewed and changes in the guidelines made if necessary.
  • Third, each dispatch criteria is given a code, called an Initial Dispatch Code (IDC) This IDC is included on all 911 Medical Incident Report forms, and allow us to compare the criteria for which the call was dispatched with the actual disposition of the patient. In this way we can examine the effectiveness of individual criteria and differences, which may exist among various paramedic or dispatch agencies. We are also able to evaluate oversends and undersends and trends in our system. An oversend is an ALS unit sent when not needed. An undersend is an ALS unit not sent when needed.

See article reference: Culley L, Eisenberg M, Horton C, et al. Criteria based dispatch sends the appropriate providers to the scene. Emergency 23(7):29-32, 1993.

EMS Online training

EMS Online is a continuing education resource that offers online, interactive courses and content for emergency medical service professionals. Originally this training program was developed by King County EMS for EMS professionals to use as an alternative for completing the cognitive objectives of the annual competency-based training (CBT) or on-going training and evaluation (OTEP) courses. Today, EMS Online continues to serve this purpose and due to the excellence of the program and demand for online training, has extended out to other organizations in Washington State and beyond. These continuing education courses are accessible only to EMS providers who have established accounts.

Contact Cleo Subido if you have questions about future trainings at

Only employees of public safety 911 centers that receive and process medical calls for service and hold a current licensing agreement with Public Health - Seattle & King County Emergency Medical Services are able to participate in trainings. If you want information on gaining employment with a 911 agency please contact one of those agencies. King County Emergency Medical Services operates a regional medical services/triage program but does not operate a 911 center.

The information packet contains some samples of CBD Guidelines, training materials and several publications. It also contains information on how to begin the process of obtaining a licensing agreement to use Criteria Based Dispatch. The copyright for the Criteria Based Dispatch Guidelines and associated training materials is held by King County Emergency Medical Services Division. We authorize the use of King County's CBD Program via a licensing agreement with Public Health - Seattle and King County EMS Division, Seattle, Washington. A copy of the boilerplate licensing agreement is enclosed in the information packet although also available to download. See also: CBD license agreement flowchart.

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