A 42-year-old woman presented to a busy urban emergency department (ED) and approached the triage nurse. The patient told the triage nurse that she had "3 days of face and tongue swelling." She also said that, in the previous 2 weeks, she had two intensive care unit (ICU) admissions for similar complaints and that she had required intubation in one of those instances.

The triage nurse documented that the patient was "speaking in full sentences" and "swallowing secretions." The vital signs at triage, including respiratory rate and oxygen saturation, were normal. The triage nurse decided that this was "urgent" and not "emergent," and therefore the patient was asked to wait in the waiting room.

The patient sat in the waiting room for more than 2 hours before she was finally placed into a room in the ED. It was another hour after that before a physician evaluated her. By that time, her tongue and throat had swollen substantially, and she was having difficulty breathing. She required emergency intubation, a potentially dangerous and high-risk procedure, and aggressive treatment with intravenous epinephrine, steroids, and nebulizers.

The patient was given a diagnosis of angioedema—rapid swelling of the skin and tissues around the mouth and throat. She was admitted to the ICU and had an uncomplicated 5-day hospital stay. The patient experienced no major long-term consequences.

The case was discussed in the departmental quality conference. When asked why she did not bring the patient into the ED more emergently, the triage nurse responded, "I didn't think the patient was telling the truth about her recent intubation."

by Debbie Travers, PhD, RN

In a perfect world, all patients presenting to the ED would be promptly evaluated by the ED caregiver. But that is not the world we live in. Instead, all EDs must employ triage: the process of categorizing patients according to severity of illness to determine treatment priority—that is, "to sort and assign the right patient to the right resources in the right place at the right time."(1,2) The triage function is a key component in keeping EDs safe, especially in the presence of ED crowding. This case illustrates some of the challenges that triage nurses face in differentiating patients who need treatment urgently or emergently from patients who can safely wait to be seen.

Emergency Department Triage Acuity Rating Systems

Triage is a critical step in the flow of patients through the ED and is typically a high-volume and high-intensity function. In most EDs, triage is performed by a nurse who evaluates patients when they first arrive. As in this case, the triage nurse's decisions directly affect the timeliness of care, and the triage process has been linked to patient outcomes. For example, under-triaged myocardial infarction patients in one study were found to have delays in electrocardiogram acquisition and reperfusion therapy.(3) In another study, differences in triage affected rates of admission for varying degrees of illness.(4) To perform triage most effectively, ED triage nurses should have a reliable, valid method of identifying which patients need to be taken from triage directly to the treatment area and which patients can safely wait.

Standardized triage acuity scales are in use in virtually all EDs in the United States to provide a method for rating the urgency of patients' presenting conditions. Historically, EDs in the United States used three-level or four-level triage scales to divide patients by severity of illness. A typical three-level acuity scale would have category labels such as emergent, urgent, and non-urgent.(1) Examples of each level are shown in Table 1. Researchers have found a higher error rate with the largely subjective three-level triage system than with newer triage acuity systems.(5-7) In addition, with three-level scales, most patients are characterized in the middle level, which provides poor discrimination of patients with clinically distinct urgency.(6,8)

In recent years, there has been growing evidence that five-level scales provide improved accuracy of triage acuity decisions.(6,9-11) Such scales allow stratification of patients into five clinically distinct categories from level 1 (resuscitation) to level 5 (non-urgent).(12,13) Examples of each level are shown in Table 2. There is no consensus in the literature regarding the amount of time that patients in each category can or do wait to be seen by a provider, though some five-level triage systems have recommended "response" times.(9,14) Five-level scales offer more accuracy in classifying the urgency of ED patients' conditions. Compared with three-level scales, the addition of two additional triage strata provides three middle levels for patients who don't need resuscitation but require more than minimal care and evaluation.

In 2004, the American College of Emergency Physicians (ACEP) and the Emergency Nurses Association (ENA) issued a joint recommendation that EDs adopt a reliable, valid five-level triage scale to support quality of patient care and move toward a standard method for triage in US EDs.(2) While no recent national data are available regarding the adoption of five-level triage, there is a trend toward five-level triage as a voluntary standard in the United States. In Canada and Australia, five-level systems are the standard for ED acuity.(14,15) Several different five-level triage scales are available, and adopting these could improve the accuracy of triage, help better manage crowded EDs, and assist in understanding daily ED operations.(2)

Many resources are available to assist EDs in implementing a robust, valid, and workable five-level triage.(13-15) Switching triage systems represents a major change for ED staff, and change management strategies can be employed to guide the process and foster adoption of the new five-level system. Standardized case scenarios have been found effective in educating triage nurses.(11,16,17) Triage audits are an effective way to monitor triage post-implementation.(13)

Let's consider the case in question. While many triage decisions hinge on generic issues like breathing and circulation, it is often necessary to understand the underlying disease process in order to triage effectively. Angioedema is a rare but potentially life-threatening condition. Patients with angioedema typically present to the ED with edema, most commonly of the tongue, face, and neck. The edema can progress rapidly, leading to airway obstruction.(18) Most patients with the acute swelling of angioedema should receive prompt attention.

Yet, this case highlights some of the challenges of triage and how using a three-level scale presents a dilemma for triage nurses in overcrowded EDs. Put yourself in the place of that nurse to see why. While the patient with tongue and facial swelling has the potential for deterioration, at the time of triage the patient had stable vital signs and was in no apparent respiratory distress. The nurse may have found it difficult to justify classifying the patient as emergent (level 1) since many patients in this category typically have unstable vital signs (e.g., low blood pressure or low oxygen saturation) and are in need of resuscitation and attention within minutes. If beds are scarce in a crowded ED, fellow staff members may disagree with a triage nurse who places a patient with stable vital signs in the last open bed. Research has shown that under-triage is more common with three-level systems.(6) If a five-level triage acuity system had been used to triage this patient, she clearly would have been classified in level 2—the level used for all patients with high-risk conditions, whether or not the patient has stable vital signs.(12,13) Past medical history is an important parameter in identifying some high-risk patients, such as this patient's history of ICU admissions and intubation. Examples of high-risk conditions that warrant a level 2 rating in a five-level triage system are provided in Table 3.

The rationale in identifying high-risk patients is that they have the potential for deterioration, as in the case of the missed angioedema patient whose tongue and facial swelling indicate a potential for airway compromise. A fundamental principle in five-level triage systems is the understanding that, while level 1 patients are clearly unstable and in need of life-saving interventions, level 2 patients are at high risk and need to be moved to the clinical area promptly for monitoring. (We need to acknowledge, of course, that the triage nurse's skepticism about this patient's clinical history may have prevented her from triaging the patient correctly. Nevertheless, the history could have increased the likelihood that the patient was seen in a timely manner.) While no triage scale can overcome human error, they can improve outcomes. Triage nurses are encouraged to err on the side of over-triage if patients seem to be on the border between two levels; this approach favors patient safety over resource allocation.

As ED crowding has worsened, many performance improvement initiatives have focused on ED patient wait times, and a common method is to stratify wait times by triage levels.(19) With the focus on reducing wait times, especially for the most acute patients, there is a potential to down-triage patients during periods of peak ED crowding. For example, if treatment areas are full and patients backed up in the waiting room, triage nurses may be inclined to rate a borderline patient level 3 (urgent) instead of level 2 (emergent). In this case, the less acute rating wouldn't necessitate that a bed be cleared. The patient would likely be sent to the waiting room. This phenomenon of "triage drift" has been suggested in the literature but has not been well studied.(4,20) This is only one of many reasons for under-triaging patients, which can still happen even in five-category triage systems.(3,16)

While the adoption of the five-category triage system can improve triage accuracy, it is not the complete answer, since many judgments remain subjective and thereby subject to errors. A promising development is the use of computerized decision support systems for triage. Dong and colleagues in Canada (4) created a standardized electronic triage tool based on the five-level Canadian Triage and Acuity Scale (CTAS) and demonstrated that the tool improved categorization of all levels, and in particular improved under-triage of level 2 patients.

Take-Home Points

• Triage is very challenging in the context of crowding, but it is critical to ED safety.
• Five-level triage is associated with more accurate triage overall, and less under-triage.
• Case studies are a key strategy for effective triage education.

Debbie Travers, PhD, RN
Assistant Professor, Health Care Systems & Emergency Medicine

School of Nursing
University of North Carolina at Chapel Hill

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14. Australian College for Emergency Medicine. Policy on the Australasian Triage Scale. [Available at]

15. Canadian Association of Emergency Physicians. Implementation Guidelines for the Canadian ED Triage and Acuity Scale (CTAS). [Available at]

16. Travers DA, Waller AE, Katznelson J, Agans R. Reliability and validity of the emergency severity index for pediatric triage. Acad Emerg Med. 2009;16:843-849. [go to PubMed]

17. Manos D, Petrie DA, Beveridge RC, Walter S, Ducharme J. Inter-observer agreement using the Canadian Emergency Department Triage and Acuity Scale. CJEM. 2002;4:16-22. [go to PubMed]

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20. Jímenez JG, Murray MH, Beveridge R, et al. Implementation of the Canadian Emergency Department Triage and Acuity Scale (CTAS) in the principality of Andorra: can triage parameters serve as emergency department quality indicators? CJEM. 2003;5:315-322. [go to PubMed]

Table 1. Examples of Three-Level Triage Acuity Scales.

Table 2. Examples of Five-Level Triage Acuity Scales.

Table 3. Examples of High-Risk Conditions (Level 2).