Implementation and refinement of the emergency severity index.
OBJECTIVES: To implement a new five-level emergency department (ED) triage algorithm, the Emergency Severity Index (ESI), into nursing practice, and validate the instrument with a population-based cohort using hospitalization and ED length of stay as outcome measures. METHODS: The five-level ESI algorithm was introduced to triage nurses at two university hospital EDs, and implemented into practice with reinforcement and change management strategies. Interrater reliability was assessed by a posttest and by a series of independent paired patient triage assignments, and a staff survey was performed. A cohort validation study of all adult patients registered during a one-month period immediately following implementation was performed. RESULTS: Eight thousand two hundred fifty-one ED patients were studied. Weighted kappa for reproducibility of triage assignments was 0.80 for the posttest (n = 62 nurses), and 0.73 for patient triages (n = 219). Hospitalization was 28% overall and was strongly associated with triage level, decreasing from 58/63 (92%) of patients in triage category 1, to 12/739 (2%) in triage category 5. Median lengths of stay were two hours shorter at either triage extreme (high and low acuity) than in intermediate categories. Outcomes followed a-priori predictions. Staff nurses rated the new program easier to use, and more useful as a triage instrument than previous three-level triage. They provided feedback, which resulted in significant revisions to the algorithm and educational materials. CONCLUSIONS: Triage nurses at these two hospitals successfully implemented the ESI algorithm and provided useful feedback for further refinement of the instrument. Emergency Severity Index triage reproducibly stratifies patients into five groups with distinct clinical outcomes.