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Definition of an Emergency Department

The definition of an emergency department (ED) is ambiguous. While it may seem obvious to many people, definitions vary greatly from country to country and even within specific countries, including the United States (US). The National Emergency Department Inventory (NEDI)-USA is a database of all hospital-affiliated EDs in the US. For NEDI purposes, we define EDs as full-service facilities open daily, at least 156 (of 168) hours per week, including on holidays. (The hourly requirement allows a maximum of 6 hours closed per day on Saturdays and Sundays.)

There are many ways to describe emergency departments, as listed below:

1. ED Location

 

a. Hospital-based

 

 

i. Independent from other hospital departments

 

 

ii. Belonging to another hospital department

 

 

iii. Independent from hospital

 

b. Non-hospital-based (freestanding)

 

 

i. Satellite (hospital-affiliated)

 

 

ii. Autonomous

 

 

iii. Primary-care-based

 

 

 

2. ED Layout

 

a. Contiguous

 

 

i. With triage to service

 

 

ii. Without triage to service

 

b. Non-contiguous

 

 

 

3. Availability

 

a. Full-time

 

b. Part-time

 

c. Seasonal

 

d. Alternating

 

 

 

4. Patients Served

 

a. General population

 

 

i. Combined

 

 

ii. Separate

 

b. Adult

 

c. Pediatric

 

d. Special population

 

 

 

5. Special Service Type

 

a. Government/Institution

 

b. Insurance-driven

 

c. Medical specialty

To provide a comprehensive overview of emergency care delivery in a country, NEDI incorporates many, but not all, of the categories listed above.

NEDI-USA includes:

  • Hospital-based full service EDs: Full service EDs located inside a hospital, (whether a general acute care hospital or a specialty hospital), including all EDs in Critical Access Hospitals (CAHs).
  • EDs that are independent departments, EDs that belong to another department in the hospital, and EDs that belong to another hospital than the one in which they are located.
  • Satellite EDs: A type of freestanding ED that is physically separate from, but affiliated with, a hospital or hospital system (provided that they belong to a hospital-based “main ED,” or the same division of the department to which the main ED belongs).
  • Satellite urgent care centers: Facilities that belong to a hospital-based main ED (or the same division of the department to which the main ED belongs) provided that they are open for at least 156 hours per week. Although called urgent care centers, these entities are very similar to a satellite ED.
  • Primary-care-based EDs: EDs in which primary care providers deliver emergency care in addition to regular primary care for at least 156 hours per week. We are not aware of any EDs in the US that fit this description.
  • Contiguous EDs: EDs in which all medical and surgical emergency care occurs in one or adjacent areas.
  • Non-contiguous EDs: EDs in which medical and surgical emergency care is provided in separate locations within a hospital.
  • EDs with triage to service: EDs in which a preliminary triage examination determines to which particular service (within the ED) a patient is sent.
  • Seasonal EDs: EDs which are open at least 156 hours per week during several months each year. These EDs are mainly found in areas whose populations are themselves seasonal (e.g., beach areas, ski resorts).
  • Alternating EDs: A pair or group of EDs which are open less than 156 hours per week but which have a formal agreement to together provide emergency care for one population for a total of at least 156 hours per week. We are not aware of any EDs in the US that fit this description.
  • EDs which closed at some point during a NEDI year, but which met our guidelines while open during that year (e.g., for 2007 NEDI-USA, an ED which closed during 2007 was still included, and data collected for the period in which it was open).
  • EDs which serve the general population (i.e., both children and adults), either in “combined” (same) or “separate” (different) locations.
  • EDs which serve primarily children or primarily adults, provided that they would at least stabilize any patient who presented to their ED for transport to another facility.
  • EDs which predominantly serve individuals with one insurance plan, provided that the ED would at least stabilize any individual presenting to the ED.
  • EDs belonging to a public or private institution (e.g., a prison or a university), provided that they are accessible to members of the general public and would at least stabilize any patient presenting to their ED. We are not aware of any EDs in the US that fit this description.

NEDI-USA does not include:

  • Autonomous EDs: Another type of freestanding ED that is physically separate from, and not affiliated with, a hospital, even if affiliated with another kind of healthcare facility.
  • Urgent care centers that meet our hourly requirement (i.e., are open for at least 156 hours per week) but which are either (1) autonomous (i.e., physically separate from and not affiliated with a hospital) or (2) located in a hospital with an already recognized ED.
  • EDs that are limited to a specific population (e.g., members of an institution, individuals with a specific insurance plan), including federal hospitals (e.g., military hospitals). As a general rule, these EDs are not accessible to all individuals. Federal hospitals that are also designated as CAHs are accessible to all individuals and, as such, are included.
  • EDs at specialty hospitals that are not “full service” because they handle only emergencies related to their specialty (e.g., psychiatric EDs at psychiatric hospitals).

The excluded ED types (above) may be included in the NEDI database for a specific country outside the US, depending on local perceptions and needs. In all such cases, analyses will be repeated without these ED types to improve comparability of data across countries.

If you have any questions, please contact the NEDI Project Coordinator at emnet@partners.org.

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©2017 EMNet Last Updated:07/09/15 er