The Emergency Severity Index (ESI) Version 5: Simulation of Predictive Validity and Triage Level Distribution

Area of Science:

• Emergency Medicine
• Healthcare Systems Analysis
• Patient Triage Systems

Background:

• The Emergency Severity Index (ESI) was updated to version 5 to better identify abnormal vital signs in low-acuity patients (ESI levels 3, 4, 5) and prevent undertriage.
• This update aims to improve patient safety by ensuring that patients who require urgent care are not misclassified into lower acuity levels.

Purpose of the Study:

• To simulate the ESI 5th version (sESI-v5) using real emergency department (ED) patient data.
• To evaluate changes in triage level distribution due to vital signs assessment in the sESI-v5.
• To assess the predictive validity of sESI-v5 concerning resource utilization, length of stay, disposition, and mortality.
• To identify specific cases that could benefit from the ESI update.

Main Methods:

• A prospective cohort study was conducted, initially using the ESI 4th version (ESI-v4) for triage.
• The sESI-v5 was applied retrospectively to the same patient data.
• Predictive validity metrics including resource utilization, ED length of stay, disposition, and mortality were compared between ESI-v4 and sESI-v5.
• Patients who were uptriaged from ESI-v4 levels 3, 4, or 5 to sESI-v5 level 2 and subsequently admitted to the ICU or experienced early death were identified as potential beneficiaries.

Main Results:

• In a cohort of 6,230 adult ED patients, 636 (10.2%) would have been uptriaged to ESI level 2 under sESI-v5.
• The sESI-v5 demonstrated comparable predictive validity to the ESI-v4.
• A total of 30 patients (0.5%) showed potential benefits from sESI-v5, defined by ICU admission or death within 30 days. Of these, 29 were uptriaged from ESI-v4 level 3, and 1 from ESI-v4 level 4.

Conclusions:

• Adopting ESI-v5 could enhance the identification of high-risk patients but may lead to a significant increase in ESI level 2 classifications.
• This potential increase in ESI level 2 patients could strain ED resources and potentially delay care for critically ill individuals, without definitive proof of improved outcomes.
• While sESI-v5 shows similar predictive validity to ESI-v4, only a small proportion of patients appear to benefit from the revised triage criteria.