Note from the Director
The Agency for Healthcare Research and Quality is pleased to bring you the Emergency Severity
Index, Version 4: Implementation Handbook. This manual covers all details of the Emergency
Severity Index (ESI)—a five-level emergency department triage algorithm that provides
clinically relevant stratification of patients into five groups from 1 (most urgent) to 5 (least
urgent) on the basis of acuity and resource needs.
After emergency physicians Richard Wuerz and David Eitel developed the ESI in 1998 and
pilot testing yielded favorable results, the ESI Triage Group was formed. Further work on the
initial development of ESI was carried out under an AHRQ grant. The ESI Triage Group, which
consisted of medical clinicians, managers, educators, and researchers, further refined the
algorithm to what it is today.
In keeping with our mission to improve the quality, safety, efficiency, and effectiveness of
health care for all Americans, one of AHRQ's areas of emphasis is training. Along with the
accompanying set of two DVDs, this handbook will provide invaluable assistance to
emergency department nurses, physicians, and administrators in the implementation of a
comprehensive ESI educational program. These materials are based on ESI Version 4, which
updates the algorithm with a particular emphasis on the expansion of ESI level 1 criteria and
refinement of the pediatric fever criteria.
A well-implemented ESI program will help hospital emergency departments rapidly identify
patients in need of immediate attention, better identify patients who could safely and more
efficiently be seen in a fast-track or urgent care center rather than the main ED, and more
accurately determine thresholds for diversion of ambulance patients from the ED.
We hope that you find this tool useful in your ongoing efforts to improve the quality of care
provided by your emergency department.
Carolyn M. Clancy, M.D.
Director
Agency for Healthcare Research and Quality
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