Chapter 6. The Role of Vital Signs in ESI Triage


In this chapter, we focus on decision point D—the patient's vital signs. To reach this point in the ESI algorithm, the triage nurse has already determined that the patient does not meet ESI level-1 or 2 criteria, and that he or she will require two or more resources. Since the patient requires two or more resources, he or she meets the criteria for at least an ESI level 3. It is at this point in the algorithm that vital signs data are considered, so the triage nurse's next step is to assess the patient's heart rate, respiratory rate, and oxygen saturation, and, when appropriate (for children under age 3), temperature. If the danger zone vital sign limits are exceeded (as illustrated in decision point D, Figure 6-1), the triage nurse must strongly consider up-triaging the patient from a level 3 to a level 2.

Figure 6-1. Danger Zone Vital Signs

Detail from ESI Triage Algorithm. Box D is labeled 'danger zone vitals?' with the following vital sign formulae: HR/RR/SaO2<92%: <3 m/>180/>50; 3 m-3y/>160/>40; 3-8 y/>140/>30; >8y/>100/>20'. An line  labeled 'Consider' leads upwards from Box D and an arrow labeled 'No' points to a 3 in a circle.

During the ESI triage educational program, a considerable amount of time should be devoted to exploring the importance of vital signs in the decision to move a patient from ESI level 3 to an ESI level 2. It should be stressed that it is always the decision of the experienced triage nurse to determine whether the patient meets criteria for ESI level 2, based upon their past medical history, current medications, and subjective and objective assessment that includes general appearance. This decision is based on the triage nurse's clinical judgment and knowledge of normal vital sign parameters for all ages and the influence of factors such as medications, past medical history, and pain level.

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What Are Vital Signs?

Vital signs traditionally include simple measurements of physiological parameters including temperature, blood pressure, pulse, and respiratory rate as well as pulse oximetry (Table 6-1). They frequently prompt a health care worker to follow a particular path of action. Recently, the nursing literature has placed increased emphasis on pain. The American Pain Society adopted the phrase "Pain: the fifth vital sign" to increase healthcare workers' awareness of the importance of assessment and management of pain. Pain assessment is an important component of ESI and is actually assessed earlier in the algorithm. So, for the purpose of ESI, heart rate, respiratory rate, oxygen saturation and temperature in children under age 3 are the vital sign parameters considered in decision point D.

Vital signs represent a set of objective data for use in determining general parameters of patients' health and viability. The values we obtain influence our interpretation of a patient's overall condition and, therefore, the path we take in establishing a diagnosis and treatment for the patient. However, vital signs alone do not paint a complete picture of the patient's condition. Vital signs may be affected by a variety of factors including prescription medications, herbals, and recreational drugs. For example, beta-blockers cause bradycardia and blunt the tachycardic response to shock. Hypothyroidism, common in the elderly, may lead to the finding of low temperature, even in the face of sepsis. A young adult may have an elevated body temperature due to recreational drug use.

Vital signs are variable, dynamic indicators that are an adjunct to a patient's evaluation. Vital sign measurements may also be operator dependent, and the definition of normal vital signs varies according to the reference consulted. Even under the best conditions, vital signs are not always reliable or accurate (Edmonds, Mower, Lovato & Lomeli, 2002). The patient's general appearance and clinical picture frequently prove to be of the most value. However, if in a triage nurse's judgment, knowing a patient's vital signs would help with risk analysis, then vital signs should be measured. For example, if the patient is using immunosuppressive medications or chemotherapy or is immunosuppressed by an illness such as AIDS, then the body temperature should be measured.

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Are Vital Signs Necessary at Triage?

Prior to the advent of five-level triage in the United States, tradition dictated that every patient presenting to an emergency department should have a set of vital signs taken before triage level assignment. Vital signs were considered an integral component of the initial nursing assessment and were often used as a decisionmaking tool. In a traditional three-level triage system, vital signs helped determine how long a patient could wait for treatment (i.e., if no abnormal vital signs were present, in many cases, the patient could wait a longer period of time). Vital signs, therefore, in the past weighted heavily in the patient triage assessment, with variable emphasis placed on the clinical presentation.

More recently, newer triage models advocate selective use of vital signs at triage (Gilboy, Travers & Wuerz, 2000). Initial vital signs are not a mandatory component of other five-level triage systems and in general are not reported during the triage phase of a level-1 or 2 patient (i.e., those patients with the highest acuity). For example, the Guidelines for Implementation of the Australasian Triage Scale in Emergency Departments states that "vital signs should only be measured at triage if required to estimate urgency, or if time permits" (Australasian College for Emergency Medicine, 2000). Similarly, the Canadian Triage and Acuity Scale (CTAS) upholds the need for vital signs if, and only if, they are necessary to determine a triage level (in the cases of levels 3, 4, and 5) as time permits (Beveridge, et al., 2002). The Manchester Triage Group uses specific vital sign parameters as discriminators within a presentational flow chart. The vital sign parameter is one of the factors that help the triage nurse assign an acuity level.

Vital signs may not always be the most appropriate tool to determine triage acuity. At least one study has suggested that vital signs are not always necessary in the initial assessment of the patient at triage. In 2002, Cooper, Flaherty, Lin, and Hubbell examined the use of vital signs to determine a patient's triage status. They considered age and communication ability as factors. Twenty-four different U.S. emergency departments and more than 14,000 patients participated in that study. Final results demonstrated that vital signs changed the level of triage acuity status in only eight percent of the cases. When further examining individual age groups, pediatric patients age 2 or younger showed the largest variation in triage decision with an 11.4-percent change once vital signs were collected.

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Vital Signs and ESI Triage

Using ESI triage, the only absolute requirement for vital signs assessment is for patients who don't initially meet ESI level-1 or 2 criteria, but who are of vital signs at triage is optional and at the discretion of the triage nurse for patients triaged as ESI level 1, 2, 4, or 5. While the ESI system does not require vital signs assessment on all patients who present to triage, local policies may dictate a different procedure. Factors such as staffing levels, casemix, and local resources influence individual hospital policies regarding vital signs at triage and are beyond the scope of this handbook. In general when triaging a stable patient, it is never wrong to obtain a set of vital signs. ESI requires vital signs for only level-3 patients (Table 6-2).

The developers of the ESI and the current ESI research team believe that experienced ED nurses can use vital sign data as an adjunct to sound clinical judgment when rating patients with the ESI. There is limited evidence on vital sign abnormalities as they relate to ED acuity and that are proven to truly represent serious illness. The ESI has been revised over time to reflect changes in the available evidence and recommendations from the literature. The ESI working group initially used the systemic inflammatory response syndrome (SIRS) literature (Rangel-Frausto, et al., 1995) in developing the danger zone vital sign box and accompanying footnotes.

The first version of the ESI used the SIRS criteria to include a heart rate of greater than 90 (for adults) as an absolute indicator to up-triage from ESI level 3 to level 2 (Wuerz, Milne, Eitel, Traers & Gilboy, 2000). The SIRS research was based on predictors of mortality in an intensive care unit population. Based on an excess of false positives using these criteria for ED patients at the initial ESI hospitals, the heart rate cutoff was changed to 100 in ESI version 2, and nurses were instructed to consider up-triage to ESI 2 for adult patients with heart rates greater than 100 (Wuerz, et al., 2001; Gilboy, Tanabe, Travers, Eitel & amp; Wuerz, 2003). Additionally, pediatric vital signs were added to the danger zone vital signs box.

When using ESI as a triage system, vital signs assessment is not necessary in the triage area for patients who are immediately categorized as level 1 or 2. If the patient appears unstable or presents with a chief complaint that necessitates immediate treatment, then transport of the patient directly to the treatment area should be expedited. For these patients, the resuscitation team is responsible for obtaining and monitoring vital signs at the bedside. This would include patients that have clinical appearances that indicate high risk or need for immediate cardiovascular or respiratory intervention. These patients may appear pale, diaphoretic, or cyanotic. However, the triage nurse has the option to perform vitals in the triage area, if an open bed is not immediately available or if he or she feels that the vital signs may assist in confirming the triage acuity level.

Some patients may not initially be identified as ESI level 1 until vital signs are taken. For example, an awake, alert elderly patient who complains of dizziness might be found to have a life-threatening condition when a heart rate of 32 or 180 is discovered during vital sign measurement.

As shown in the ESI algorithm in Chapter 3, if patients do not meet ESI level-1 or 2 criteria, the triage nurse comes to decision point C. The nurse then determines how many resources the patient is expected to need in the ED. If the patient is expected to need one or no resources, he or she can be assigned an ESI level of 4 or 5 and no vital sign assessment is necessary. But if the patient is expected to need two or more resources, then the nurse comes to decision point D and vital signs should be assessed.

Vital signs can play a more important role in the evaluation of some patients at triage, especially those triaged as ESI level 3. The range of vital signs may provide supporting data for potential indicators of serious illness. If any of the danger zone vital signs are exceeded, it is recommended that the triage nurse consider up-triaging the patient from level 3 to level 2.

Vital signs that are explicitly included in ESI triage are heart rate, respiratory rate, and oxygen saturation (for patients with potential respiratory compromise). Temperature is specifically used in ESI triage for children under age 3. It is important to note that when considering abnormal vital signs, blood pressure is not included in the ESI algorithm. This does not mean that the triage nurse should not take a blood pressure or a temperature on older children or adults but that these vital signs are not necessarily used to assist in selecting the appropriate triage acuity level.

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Vital Signs and Pediatric Fever

In this version of the ESI Handbook, version 4 (v.4) of the ESI algorithm has been updated to include more current pediatric fever criteria. As shown in Figure 6-2, note D of the ESI algorithm addresses pediatric fever considerations for ESI triage. This section incorporates recommendations from the American College of Emergency Physicians' Clinical Policy for Children Younger Than Three Years Presenting to the Emergency Department With Fever (ACEP, 2003).

Figure 6-2. Danger Zone Vital Signs

D. Danger Zone Vital Signs. Consider uptriage to ESI 2 if any vital sign criterion is exceeded.

Pediatric Fever Considerations:
  1. 1 to 28 days of age: assign at least ESI 2 if temp >38.0 C (100.4F)
  2. 1-3 months of age: consider assigning ESI 2 if temp >38.0 C (100.4F)
  3. 3 months to 3 yrs of age: consider assigning ESI 3 if: temp >39.0 C (102.2 F), or incomplete immunizations, or no obvious source of fever.

The ESI Triage Research Team recommends that vital signs in patients under age 3 be assessed at triage. In particular, temperature measurement is important during triage of all children from newborn through 36 months of age, and vital sign evaluation is essential to the overall assessment of a known febrile infant under age 36 months (Baraff, 2000). This helps to differentiate ESI level-2 and 3 patients and minimize the risk that potentially bacteremic children will be sent to an express care area or otherwise experience an inappropriate wait. Remember, if a patient is in immediate danger or high risk, he or she will be assigned to either ESI level 1 or 2.

Table 6-3 provides direction for the triage nurse in using the ESI to assess the febrile child and determine the most appropriate triage level. The generally accepted definition of fever is a rectal temperature greater than 38.0° C (100.4° F) (Baraff, et al., 1993; ACEP, 2003). The infant less than 28 days old with a fever should be considered high risk and assigned to at least ESI level 2. There are no clear guidelines for the infant between 28 days and 3 months of age. The ESI research team recommends triage nurses rely on local hospital guidelines. We suggest that the nurse consider assigning at least an ESI level 2 for such patients.

In v. 4 of the ESI, we have incorporated a different set of pediatric fever guidelines for children ages 3 to 36 months. These pediatric fever considerations pertain to highly febrile children, defined as those with a fever of greater than 39.0° C (102.2° F) (ACEP, 2003). When triaging a child between 3 and 36 months of age who is highly febrile, it is important for the triage nurse to assess the child's immunization status and whether there is an identifiable source for the fever.

The patient with incomplete immunizations or with no identifiable source for the fever should be assigned to at least ESI level 3. If the patient has an identifiable source for the fever and his or her immunizations are up to date, then a rating of 4 or 5 is appropriate. For example, a 7-month-old who is followed by a pediatrician, has had the Haemophilus influenza type b (HIB) vaccine and presents with a fever and pulling on his ear could be assigned to an ESI level 5.

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Case Examples

The following case studies are examples of how vital signs data are used in ESI triage:

This patient meets the criteria for being up-triaged from a level 3 to a level 2 based on her vital signs. Her increased heart rate, respiratory rate, and decreased blood pressure are a concern. These factors could indicate internal bleeding from a ruptured ectopic pregnancy.

This patient meets the criteria for at least ESI level 3. For resources he would require labs and IV fluid. Based on his vital signs the triage nurse can uptriage him to an ESI level 2. For a baby this age, both heart rate and respiratory rate criteria are violated.

At the beginning of her triage assessment, this patient sounds as though she could have pneumonia. She will need two or more resources but her low oxygen saturation and increased respiratory rate are a concern. After looking at her vital signs the triage nurse should up-triage the patient to an ESI level 2.

This patient will need a minimum of two or more resources: lab, IV fluids, perhaps IV medication for nausea, and a CT scan. The triage nurse would review the patient's vital signs and consider the heart rate. The heart rate falls just outside the accepted parameter for the age of the patient but could be due to pain or exertion. In this case, the decision should be to assign the patient to ESI level 3.

This child is experiencing pain from her fall and is obviously upset. She will require at least two resources: x-ray and orthopedic consult, and perhaps conscious sedation. Her heart rate and respiratory rate are elevated, but the triage nurse should feel comfortable assigning this patient to ESI level 3. Her vital sign changes are likely due to pain and distress.

This patient will require two or more resources: labs and IV antibiotics. She meets the criteria for ESI level 3. The triage nurse notices that her oxygen saturation and respiratory rate are outside the accepted parameters for the adult but this patient has advanced COPD. These vital signs are not a concern so the patient will not be up-triaged but will stay an ESI level 3.

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The information in this chapter provides a foundation for understanding the role of vital signs in the Emergency Severity Index triage system. We addressed the special case of patients under 36 months of age. Further research is necessary to clarify the best vital sign thresholds used in emergency department triage. Further study will also examine pediatric populations presenting to the emergency department. It is our hope that future versions of the ESI will be based on additional evidence regarding the predictive value of triage vital signs for pediatric and adult patients.

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American College of Emergency Physicians (2003). Clinical policy for children younger than 3 years presenting to the emergency department with fever. Annals of Emergency Medicine 43(4):530-45.

Australasian College for Emergency Medicine (2000). Policy document—the Australasian triage scale. Retrieved March 27, 2002, from

Australasian College for Emergency Medicine (2000). Guidelines for the implementation of the Australasian triage scale in emergency departments. Retrieved March 27, 2002, from

Baraff LJ (2000). Management of fever without source in infants and children. Annals of Emergency Medicine 36:602-14.

Baraff LJ, Bass JW, Fleisher GR, Klein JO, McCracken GH, Powell KR, et al. (1993). Practice guideline for the management of infants and children 0 to 36 months of age with fever without source. Agency for Health Care Policy and Research. Annals of Emergency Medicine 22:1198-210.

Beveridge R, Clarke B, Janes L, Savage N, Thompson J, Dodd G, et al. Implementation guidelines for the Canadian emergency department triage and acuity scale (CTAS). Retrieved March 27, 2001, from

Cooper R, Flaherty H, Lin E, Hubbell K (2002). Effect of vital signs on triage decisions. Annals of Emergency Medicine 39:223-32.

Edmonds Z, Mower W, Lovato L, Lomeli R (2002). The reliability of vital sign measurements. Annals of Emergency Medicine 39:233-7.

Gilboy N, Travers DA, Wuerz RC (2000). Reevaluating triage in the new millennium: A comprehensive look at the need for standardization and quality. Journal of Emergency Nursing 25(6):468-73.

Gilboy N, Tanabe P, Travers DA, Eitel DR, Wuerz RC (2003). The Emergency Severity Index Implementation Handbook: A five-level triage system. Des Plaines, IL: Emergency Nurses Association.

Paris P (1989). No pain, no pain. American Journal of Emergency Medicine 7:660.

Rangel-Frausto M, Pittet D, Costigan M, Hwang T, Davis C, Wenzel R (1995). The natural history of the systemic inflammatory response syndrome (SIRS): A prospective study. Journal of the American Medical Association 273:117-23.

Stedman's Medical Dictionary (26th ed.) (1995). Baltimore: Williams & Wilkins.

Tintinalli J, Kelen G, Stapczynski J (2000). Emergency medicine: A comprehensive study guide (5th ed.). New York: McGraw-Hill.

Wuerz R, Milne LW, Eitel DR, Travers D, Gilboy N (2000). Reliability and validity of a new five-level triage instrument. Academic Emergency Medicine 7(3):236-42.

Wuerz R, Travers D, Gilboy N, Eitel DR, Rosenau A, Yazhari R (2001). Implementation and refinement of the emergency severity index. Academic Emergency Medicine 8(2):170-6.

Note: Appendix A of this handbook includes frequently asked questions and post-test assessment questions for Chapters 3 through 8. These sections can be incorporated into the ESI training course.

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