What are the Emergency Severity Index (ESI) triage recommendations?

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Last updated: March 25, 2025View editorial policy

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From the Guidelines

The Emergency Severity Index (ESI) triage system is recommended for emergency departments, with stroke patients categorized as level 2, requiring immediate assessment. This recommendation is based on the American College of Emergency Physicians and the Emergency Nurses Association's endorsement of the 5-level ESI system as a preferred triage method in busy EDs 1. The ESI system prioritizes patients based on acuity and resource needs, with level 2 indicating high-risk situations or severe pain/distress, such as stroke patients.

Key Components of ESI Triage

  • Implement a 5-level ESI system, where:
    • Level 1 represents patients requiring immediate life-saving interventions
    • Level 2 is for high-risk situations or severe pain/distress, including stroke patients
    • Level 3 is for multiple resources needed but stable vital signs
    • Level 4 is for one resource needed
    • Level 5 is for no resources required
  • Train triage nurses in standardized ESI methodology, including vital sign assessment and recognition of high-risk presentations, such as neurological symptoms suggesting stroke 1
  • Reassess patients waiting longer than recommended timeframes, with immediate reassessment for Level 1 patients, and regular reassessments for other levels

Importance of Timely Triage and Treatment

The ESI system's effectiveness in improving patient outcomes stems from its combination of acuity assessment with anticipated resource utilization, creating a more nuanced prioritization than simpler triage models. For stroke patients, timely triage and treatment are critical, as studies have shown that the sooner thrombolytic therapy is started, the greater the benefit 1. The NIH-National Institute of Neurological Disorders and Stroke (NINDS) benchmark treatment time for AIS with intravenous rtPA is within 60 minutes of arrival in the ED.

Additional Considerations

  • Use specialized checklists, protocols, and other tools to identify stroke patients and rapidly assess the initial time of symptom onset or the last known well time 1
  • Consider common stroke mimics, such as hypoglycemia, which can be quickly identified by measuring blood glucose during transport 1

From the Research

Emergency Severity Index (ESI) Triage Recommendations

The Emergency Severity Index (ESI) is a five-level triage acuity scale used to assess patients in emergency departments. The ESI levels range from 1 (highest acuity) to 5 (lowest acuity) 2.

ESI Triage Levels

  • ESI level 1: highest acuity, requires immediate intervention 2
  • ESI level 2: high acuity, may require immediate intervention or can wait for at least ten minutes 2
  • ESI level 3: moderate acuity, may be up-triaged to level 2 based on vital signs such as respiratory rate, heart rate, or oxygen saturation 3
  • ESI level 4 and 5: lower acuity, may not require immediate intervention 4

Up-Triage Recommendations

  • Patients with danger zone respiratory rate, heart rate, or oxygen saturation should be up-triaged from ESI level 3 to 2 3
  • Abnormal findings in respiratory rate and heart rate are more common reasons for up-triage from ESI level 3 to 2 compared to oxygen saturation 3

Limitations of ESI Triage

  • ESI score is poorly associated with serious outcomes in patients with suspected acute coronary syndrome 5
  • Supplementing ESI with other validated clinical tools can improve the accuracy of triage in patients with suspected acute coronary syndrome 5
  • Higher acuity patients may face inappropriate stratification and longer waiting times 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Refining Emergency Severity Index triage criteria.

Academic emergency medicine : official journal of the Society for Academic Emergency Medicine, 2005

Research

The Emergency Severity Index 5-level triage system.

Dimensions of critical care nursing : DCCN, 2009

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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