Implementation Handbook

Emergency Severity Index, Version 4


The Emergency Severity Index (ESI) is a five-level emergency department (ED) triage algorithm that provides clinically relevant stratification of patients into five groups from 1 (most urgent) to 5 (least urgent) on the basis of acuity and resource needs.The Agency for Healthcare Research and Quality (AHRQ) funded initial work on the ESI.

A well-implemented ESI program will help hospital emergency departments rapidly identify patients in need of immediate attention, better identify patients who could safely and more efficiently be seen in a fast-track or urgent care center rather than the main ED, and more accurately determine thresholds for diversion of ambulance patients from the ED.

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Contents

Note from the Director
Preface
Copyright Notice
1: The Evolution of Triage
2: Triage Acuity Systems
3: Introduction to the Emergency Severity Index
4: ESI Level 2
5: Expected Resource Needs
6: The Role of Vital Signs in ESI Triage
7: Implementation of ESI Triage
8: Evaluation and Quality Improvement
9: Practice Cases
10: Competency Cases
Appendixes
Appendix A: Frequently Asked Questions and Post-Test Materials for Chapters 3-8
Appendix B: ESI Triage Algorithm, v. 4


Chapter 1. The Evolution of Triage

The purpose of emergency department (ED) triage is to prioritize incoming patients and to identify those patients who cannot wait to be seen. The experienced triage nurse is able to rapidly and accurately identify the small percentage of patients requiring immediate care. The triage nurse is then challenged to sort the remaining large number of patients who do not require immediate treatment and can wait for physician evaluation. The number of patients presenting to emergency departments is increasing, and this trend is not likely to change. As EDs are struggling to cope with overcrowding there is a critical need for a valid, reliable triage acuity rating system in order to sort these incoming patients more rapidly and accurately.

This chapter explores the evolution of triage in the United States and describes the dominant triage systems currently in use in EDs. A discussion follows of why the acuity ratings scales currently in place in most emergency departments are no longer adequate to meet the needs of the 21st century in light of recent trends in patient demographics, ED utilization, and other factors affecting patient flow through the ED.

Triage History

The word "triage" is derived from the French verb "trier," to "sort" or "choose." Originally the process was used by the military to sort soldiers wounded in battle for the purpose of establishing treatment priorities. Injured soldiers were sorted by severity of their injuries ranging from those that were severely injured and deemed not salvageable, to those who needed immediate care, to those that could safely wait to be treated. The overall goal of sorting was to return as many soldiers to the battlefield as quickly as possible.

Changes in the health care delivery system forced U.S. emergency departments to consider alternative ways of handling an increase in the number of incoming patients during the 1950s and early 1960s. In the late 1950s, physician practice began to change. Physicians moved away from solo practice; the days of house calls and the family doctor became nearly obsolete. Physicians formed office-based group practices that offered regular office hours with appointments. Emergency departments became the principal provider of primary medical care when doctors' offices were closed, principally during evenings and weekends. At the same time, more physicians entered specialties rather than general practice. Emergency departments started to experience a large increase in volume. The increased volume was a result of use of the ED by patients with lower acuity problems. Emergency departments recognized they needed a method to sort patients and identify those needing immediate care. This provided the impetus to put ED triage systems into place. Physicians and nurses who had used the triage process effectively in the military first introduced triage into civilian EDs. The transition of the triage process from the military to U.S. emergency departments was extremely successful.

Thompson and Dains (1982) identified the three most common types of triage systems:

Traffic director is the simplest type of system. A nonclinical employee greets the patient and directs the patient to a treatment area or the waiting room based on their initial impression. By 2002, this type of system no longer worked effectively.

The second type of triage is a spot-check triage system, appropriate for a low volume emergency department where it is not cost effective to always have an RN at triage since patients do not need to wait. Instead, a registration person greets the patient and pages the triage nurse when a patient presents. The RN then determines patient acuity based on a brief triage assessment. Patient assessment is a nursing function that cannot be delegated to less qualified personnel.

Comprehensive triage, the most advanced system, has continued to evolve in the United States. It is supported by the Emergency Nurses Association (ENA) Standards of Emergency Nursing Practice:

The emergency nurse triages each patient and determines the priority of care based on physical, developmental and psychosocial needs as well as factors influencing access to health care and patient flow through the emergency care system.

Triage is to be performed by an experienced ED nurse who has demonstrated competency in the triage role. The goal is to rapidly gather "sufficient" information to determine triage acuity (ENA, 1999, p. 23).

Though it is recommended that comprehensive triage is to be completed in 2 to 5 minutes, Travers (1999) demonstrated at one tertiary center ED that this goal was only met 22 percent of the time.

Triaging pediatric and elderly patients has been found to take more time than other patients. The level of detail necessary for comprehensive triage can be difficult for the experienced nurse to complete in a short timeframe such as 2 to 5 minutes. The triage nurse is expected to obtain a complete history, take vital signs and complete department-specific screening questions. Sufficient information must be obtained to make the correct triage decision. Under-triage in the era of ED overcrowding can compromise patient safety.

Emergency nurses must question whether we have set unrealistic standards for ourselves and whether the distinction between a comprehensive triage assessment and initial assessment remains clear. A comprehensive triage system can lead to a backlog of patients waiting to be seen by the triage nurse. In an attempt to facilitate the flow of patients through high-volume emergency departments and to ensure that no patient waits to be seen by a triage nurse, two-tier or two-step triage systems have evolved. An experienced triage nurse greets the patient and decides whether the patient can safely wait for further assessment and registration or whether they should go directly to the patient care area. The decision is based on chief complaint and an "across-the-room assessment."

The introduction of triage systems into emergency departments in the 1960s, 1970s, and 1980s had a number of clear benefits for patients and for the department. Some of the benefits included:

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Triage Acuity

Today most emergency departments in the United States use some type of triage acuity system. A triage acuity system is used to communicate to the clinical staff in the department which patient can safely wait and which patient needs to be seen immediately.

In 2001, the Emergency Nurses Association surveyed U.S. emergency departments about the type of triage acuity scale used by their department (MacLean, 2002). The survey included responses from 1,380 emergency department managers, which represent approximately 27 percent of all EDs in the United States. Sixty-nine percent of the emergency departments used a three-level scale, 12 percent used a four-level scale, 3 percent used either the Australasian or Canadian five-level scale, and 16 percent did not answer the question or used no triage acuity rating scale.

More recent data reflect a trend towards five-level triage. In 2003, the National Center for Health Statistics found that 47 percent of EDs used three-level triage systems, while 20 percent used four-level and 20 percent used five-level systems (personal communication, Catharine Burt, November 1, 2004).

The commonly used three-level scale includes these acuity levels:

Patients are rated as emergent if they have a problem that poses an immediate life or limb threat (ENA, 2001). Patients considered urgent are those that require prompt care, but can wait up to several hours if necessary. Nonurgent patients have conditions that need attention, but time is not a critical factor.

As emergency departments and the health care system have continued to change, the value of the existing acuity rating scales have come under increasing scrutiny. This scrutiny led to research which found traditional triage models inadequate. In particular, emergency medicine and emergency nursing leaders question the reliability and validity of the three-level acuity-rating scale being used by the majority of EDs in the United States. The definitions of emergent, urgent, and nonurgent are unclear, not uniform and are often hospital dependent and nurse dependent. Wuerz, Fernandes, and Alarcon (1998) measured the interrater and intrarater agreement of three-level triage. Agreement was measured with the kappa statistic, which ranges from 0 (no agreement) to 1 (perfect agreement).

Triage nurses and emergency medical technicians (EMTs) at two hospitals were asked to rate the acuity of five scripted patient scenarios using a three-level scale. Six weeks later participants were asked to again rate the same scenarios. Only 24 percent of participants rated all five cases the same in both phases. The overall kappa statistic for severity rating was 0.35, which shows poor agreement among nurses.

Rapid, accurate triage of patients is key to successful emergency department operations in the 21st century. In particular, the triage nurses' initial acuity categorization is critical. Under-categorization (undertriage) leaves the patient at risk for deterioration while waiting. Initial overcategorization (overtriage) uses scarce resources, limiting availability of an open ED bed for another patient who may require immediate care. For these reasons, the initial triage categorization by the triage nurse must be as accurate as possible. Accurate triage categorization can only be accomplished by the use of a reliable and valid triage acuity system in which all ED nurses have been adequately trained. Initial triage categorization is not as important in small, low volume emergency departments where there is often no wait to be seen. Unfortunately, this is not the case for most EDs throughout the United States. However, an important benefit of using a valid and reliable triage system is the ability to use triage data to describe ED casemix. Therefore, using a valid and reliable triage system is also important in low-volume EDs.

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Recent Trends Affecting Emergency Departments

Many opposing forces affect our ability to provide quality care and maximize patient flow through the ED. Emergency department overcrowding is a well-documented problem in the United States today; patient volumes continue to rise for many reasons and this trend is not likely to change in the near future (Adams & Biros, 2001; Derlet, Richards, & Kravitz, 2001; Taylor, 2001). The American Hospital Association (2002) reported 90 percent of hospital emergency departments perceive they are at or over operating capacity. This translates into longer waiting times to be seen and longer lengths of stay in the ED. The average waiting time to be seen by an emergency physician in 2001 was 49 minutes, which represented an increase of 11 minutes from 1997 (McCaig & Ly, 2002).

Factors contributing to the increase in ED patient volumes and waiting times include a decrease in the number of U.S. emergency departments, aging of the general population, longer lengths of ED stays, an inability to move admissions into the hospital because of a decreased number of inpatient beds due to hospital closings and downsizing, an increase in the number of uninsured patients, poor access to primary care, and a nursing shortage which often leaves open beds unable to be used due to lack of nursing staff. The impact of these issues on triage will be discussed in detail.

The number of visits to emergency departments in the United States is continuing to grow. The National Hospital Ambulatory Medical Care Survey: 2002 Emergency Department Summary reports an estimated 110 million visits were made to emergency departments in 2002 (McCaig & Burt, 2004). This represents an increase of 23 percent between 1992 and 2002, with an average of 38.9 visits per 100 persons in 2004.

The highest rate of ED visits is by persons age 75 and older. This rate is approximately 61.1 visits per 100 persons (McCaig & Burt, 2004). The U.S. Census Bureau (1996) reports that the number of persons in the 65 to 74 age group and in the 75 and older category will continue to grow rapidly. In 1990 there were approximately 10 million persons in the 75 and older age group. This number is projected to grow to 23 million by 2030. One in eight Americans was 65 and older in 1994; by 2030 this ratio will change to about one in five. This age group has the highest number of emergency department visits; thus, it is expected that EDs will see a continuing increase in the number of visits by the elderly population each year.

There were approximately 39 million uninsured persons in the United States in 2001 and that number is continuing to rise (U.S. Department of Health and Human Services, 2002). Individuals may be uninsured because they lack access to a group plan or are unable to afford the cost of health insurance. The number of immigrants with health insurance is low (Velianoff, 2002). Many of these individuals are using and will continue to use emergency departments for primary care.

The actual number of emergency departments in the United States has continued to decline (McCaig & Ly, 2002). Over the 3-year period from 1997 to 2000, the number of hospital emergency departments decreased from 4,005 to 3,934. As the demand for ED services continues to increase, the number of annual visits to each emergency department has increased 14 percent on average.

At the same time, the actual number of hospital beds across the country has decreased. For example, the American Hospital Association reports that between 1994 and 1998 the number of inpatient beds nationwide dropped 8 percent (Shute & Marcus, 2001). As a result emergency departments are experiencing difficulty moving admitted patients into the hospital, at times creating gridlock. Hospitals are making changes to cope with the volume. For example, systems are being put into place to clean rooms more efficiently and physicians are being asked to make rounds and discharge patients earlier in the day. Despite these efforts, the average emergency department length of stay for both admitted and discharged patients is increasing. Anecdotal reports of patients staying in an ED for days are no longer uncommon.

The nursing shortage is another factor that has impacted emergency department overcrowding. Most emergency departments are facing serious staffing issues and are increasingly turning to new and/or inexperienced ED nurses. The average ED RN is very experienced but is 45 years of age, working harder, and concerned about the increased volume. For many, the solution is leaving for a position that is less stressful and offers more control over their own assignment. In-house nursing shortages directly affect the ED, as some open beds cannot be filled due to the unavailability of a nurse to staff the bed.

Emergency departments are in a unique and challenging position with regard to controlling patient flow in and out of the unit. As opposed to inpatient units that don't admit patients when they are full, EDs have generally been thought of as units that are always open, with a potentially limitless capacity for patients. Most emergency departments have little control over when admissions can be transferred from the ED to their assigned inpatient bed. One option for the overcrowded ED is to try to control the "front end," or the number of patients presenting for care. Some hospitals have the ability to close to ambulance traffic for a period of time, which is known as "going on diversion" or bypass.

This is a strategy EDs can use when they are overcrowded and unable to safely care for any additional patients. This strategy may buy an emergency department time to deal with the patients already in the department; however, it is not a panacea for the problem of overcrowding. Due to their remote location some hospitals do not have the option to divert ambulances. Diversion is not an absolute solution, since 75 percent of patients arrive at the emergency department by means other than ambulances (McCaig & Ly, 2002).

Clearly a busy emergency department can lead to delays in care. One problem related to the increase in volume is emergency departments seeing an increased number of patients who are choosing to leave prior to a medical screening exam (Derlet, 2002). The patient may recognize that the wait to see a physician is significant and they decide to leave without being seen. While some of these patients may have less urgent conditions and suffer no ill effects by leaving the ED, others may be at risk for serious consequences by not receiving treatment. Those patients who stay may endure long waits and suffer adverse events.

In June 2002, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) released a Sentinel Event Alert (JCAHO, 2002). JCAHO identified emergency departments as the source for more than half the reported sentinel event cases of patient death or permanent disability due to delays in treatment. In 31 percent of the cases, overcrowding was identified as a contributing factor.

The causes and effects of ED overcrowding are complex and difficult to define, and researchers continue to develop metrics to measure them (Derlet, Richards & Kravitz, 2001; Weiss et al., 2004). Many models identify increasing patient acuity as a major factor in ED overcrowding, and in some studies researchers have used triage ratings to represent ED patient acuity (Derlet & Richards, 2000; Liu, Hobgood & Brice, 2003). It is even more important to move beyond defining overcrowding and examining the effects of overcrowding on patient outcomes. The triage decision is an important element to be examined. Due to the prevalence of overcrowding, many EDs are actually beginning to implement protocols that involve a physician or nurse practitioner role at triage. The benefits and cost-effectiveness of this arrangement need to be studied.

In many ways emergency departments today are facing the same major issues seen in the late 1950s and early 1960s. At that time EDs were dealing with an increase in volume. No method was in place to identify the patient who needed to be seen immediately from the one who could wait safely.

Patient safety was a major concern. One solution was the introduction of basic triage principles into the emergency department. Today, EDs are once again facing the issues of overcrowding and finding that some of the triage solutions put into place in the 1950s are no longer effective. The current state of overcrowding threatens patient safety and has caused an increased focus on triage. The triage process, use of standing orders, and a physician or nurse practitioner role at triage are all important concepts that need to be examined to optimize safety of the triage process. Attention to adequate training of triage nurses is another critical element that requires attention.

While all of these issues are important, the selection of a reliable and valid triage system is a fundamental decision to help begin to address safety at triage. Current triage acuity systems are inadequate given the complex issues facing EDs. There is a need to replace the traditional triage acuity system with a research-based, valid, and reliable system. The Emergency Severity Index (ESI), which is introduced in Chapter 3, can provide EDs with a reliable, valid triage system. The ESI is a triage system that accurately identifies those patients who need to be seen immediately from those patients who can safely wait to be seen. The ESI is discussed in detail in subsequent chapters of the handbook.

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References

Adams JG, & Biros MH (2001). The endangered safety net: Establishing a measure of control. Academic Emergency Medicine 8(11):1013-5.

American Hospital Association (2002). Emergency department overload: A growing crisis. Medical Benefits 19(10):8.

Derlet RW (2002). Overcrowding in emergency departments: Increased demand and decreased capacity. Annals of Emergency Medicine 39(4):430-2.

Derlet RW, & Richards JR (2000). Overcrowding in the nation's emergency departments: Complex causes and disturbing effects. Annals of Emergency Medicine 35(1):63-8.

Derlet RW, Richards JR, Kravitz RL (2001). Frequent overcrowding in U.S. emergency departments. Academic Emergency Medicine 8(2):151-5.

Emergency Nurses Association (1997). Triage: Meeting the challenge. Park Ridge, IL: Author.

Emergency Nurses Association (1999). Standards of emergency nursing practice (4th ed.). Des Plaines, IL: Author.

Emergency Nurses Association (2001). Making the right decision: A triage curriculum (2nd ed.). Des Plaines, IL: Author.

Joint Commission on Accreditation of Healthcare Organizations (JCAHO) (2002). Delays in treatment. Sentinel Event Alert 26:1.

Liu S, Hobgood C, & Brice JH (2003). Impact of critical bed status on emergency department patient flow and overcrowding. Academic Emergency Medicine 10(4):382-5.

MacLean S (2002). 2001 ENA national benchmark guide: Emergency departments. Des Plaines, IL: Emergency Nurses Association.

McCaig LF & Burt CW (2004). National hospital ambulatory medical care survey: 2002 emergency department summary. Advance Data from Vital and Health Statistics 340. Hyattsville, MD: National Center for Health Statistics.

McCaig LF & Ly N (2002). National hospital ambulatory medical care survey: 2000 emergency department summary. Advance Data from Vital and Health Statistics 326:1-31. Hyattsville, MD: National Center for Health Statistics.

Shute N & Marcus M (2001). Code blue crisis in the ER. U.S. News and World Report 131(9):54-61.

Taylor TB (2001). Emergency services crisis in 2000—The Arizona experience. Academic Emergency Medicine 8(11):1107-8.

Thompson J & Dains J (1982). Comprehensive triage. Reston, VA: Reston Publishing Company, Inc.

Travers D (1999). Triage: How long does it take? How long should it take? Journal of Emergency Nursing 25(3):238-40.

United States Bureau of the Census (1996). Current population reports, Special Studies, 65+ in the United States (pp. 23-190). Washington, DC: U.S. Government Printing Office.

United States Department of Health and Human Services. (2002). Health insurance coverage improves for American children. HHS News 02(04):1.

Velianoff, G. (2002). Overcrowding in the emergency department: The health care safety net unravels. Nursing Clinics of North America 37(1):59-65.

Weiss SJ, Derlet R, Arndahl J, Ernst AA, Richards J, Fernandez-Frankelton M, et al. (2004). Estimating the degree of emergency department overcrowding in academic medical centers: Results of the national ED overcrowding study (NEDOCS). Academic Emergency Medicine 11(1):38-50.

Wuerz RC, Fernandes CM & Alarcon J (1998). Inconsistency of emergency department triage. Emergency department operations research working group. Annals of Emergency Medicine 32(4):431-5.

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