The Emergency Severity Index (ESI) is a five-level

emergency department An emergency department (ED), also known as an accident and emergency department (A&E), emergency room (ER), emergency ward (EW) or casualty department, is a medical treatment facility specializing in emergency medicine, the acute care of pati ...

triage algorithm, initially developed in 1999. It was previously maintained by the Agency for Healthcare Research and Quality (AHRQ), but is currently maintained by the

Emergency Nurses Association The Emergency Nurses Association (ENA) is the premier professional organization that represents emergency nursing. Consisting of more than 50,000 members, ENA addresses issues relevant to emergency care, publishes professional guidelines, provides ...

(ENA).

Algorithm

ESI triage is based on the acuity of patients' health care problems and the number of resources their care is anticipated to require. This differs from standardized triage algorithms used in several other countries, such as the Australasian Triage Scale, which attempt to divide patients based on the time they may safely wait. The concept of a "resource" in ESI means types of complex interventions or diagnostic tools, above and beyond physical examination. Examples of resources include

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

, blood tests, sutures, and

intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...

intramuscular Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have l ...

medications. Oral medications and prescriptions are specifically not considered resources by the ESI algorithm. The ESI levels are numbered one through five, with level one indicating the greatest urgency. However, levels 3, 4, and 5 have are determined not by urgency, but by the number of resources expected to be used as determined by an experienced nurse. The levels are as follows:

References

Diagnostic emergency medicine Management cybernetics Triage {{emergency-services-stub