The story of how the Emergency Severity Index was inititally developed and now practiced both across the country and in international footprints. 



Emergency Severity Index brand and website relaunched. 


The Emergency Severity Index web course for Pediatrics released in English. 


Spanish Version of the ESI web course released.


Results of the National Opinion Research Center (NORC) Evaluation of ESI published in the Journal of Emergency Nursing. 


ESI web course released.


The National Opinion Research Center (NORC) completed a formal evaluation of ESI and gave it to the Agency for Healthcare Research and Quality (AHRQ). 

2006 - 2009 

Evaluation of ESI reliability and validity for pediatric triage in 7 emergency departments in 3 states. Sites include: 

  • University of North Carolina Hospitals, Chapel Hill, NC
  • Wake Med Children’s, Raleigh, NC
  • Lehigh Valley Hospital, 17th Street Allentown, PA
  • Lehigh Valley Hospital, Muhlenberg, Bethlehem, PA
  • York Hospital, York, PA
  • Intermountain Primary Children’s Hospital, Salt Lake City, Utah


High acuity criteria revised and ESI Version 4 released. AHRQ published revised handbook, ESI Version 4 Implementation Handbook and training DVDs.


ESI Version 3 released. ESI Handbook first published by the Emergency Nurses Association.


Refinement and implementation of the ESI in 5 additional hospitals. AHRQ-funded study of ESI reliability and validity in 7 emergency departments in 3 states. Sites include: 

  • University of North Carolina Hospitals, Chapel Hill, NC
  • Brigham & Women’s Hospital, Boston, MA
  • York Hospital, York, PA
  • Faulkner Hospital, Boston, MA
  • Lehigh Valley Health Network, Allentown, PA


Pilot testing of the ESI completed and the results were promising. Drs. Wuerz and Eitel brought together a number of emergency professionals interested in triage and further refined the algorithm.

May 1999

Initial ESI implementation at the University of North Carolina Hospitals in Chapel Hill, North Carolina and at Brigham and Women’s Hospital in Boston. Post-implementation and refinement study at UNC and Brigham and Women’s Hospitals.


Emergency physicians, Richard Wuerz and David Eitel developed the original ESI concept and initiated pilot testing.