Modern Triage in the Emergency Department (2024)

Table

ATS, Australasian Triage Scale (previously National Triage Scale, NTS); CTAS, Canadian Triage and Acuity Scale; MTS, Manchester Triage Scale; ESI, Emergency Severity Index; n. s., not specified; I to V: triage priority levels. For some instruments no time limits are defined for first contact with a doctor after arrival at the emergency department. In the ATS and CTAS, adherence to these time limits is recorded as an indicator describing emergency department performance. For example, in ATS triage levels I and II at least 97.5% and at least 95% of patients, respectively, should be seen by a doctor within the defined time limits. These data are published in the performance reports of emergency departments in Australia (ATS) and Canada (CTAS), serve as reference data, and to a certain extent have an effect on reimbursem*nt

eTable

w, weighted statistic; n.s., not stated or not applicable

Validity of a triage instrument

A method is described as “valid” if its results agree with the “true” value. With regard to triage systems, the assigned priority level should correspond with the actual degree of urgency. In the absence of a gold standard for the genuine degree of urgency, surrogate markers such as rate of hospital admission, rate of admission to intensive care, mortality rate, and utilization of resources are used to assess validity (5, 9).

Reliability of a triage instrument

The reliability or replicability of the results should be as high as possible; otherwise the method is not sufficiently dependable (5). Ideally, different investigators should come to the same conclusions regarding treatment priority. Reliability is described using the kappa statistic, where κ = 0 indicates a random result and κ = 1 shows total agreement between two or more measurements. Agreement is classified as follows: poor (κ<0.2), adequate (0.2<κ<0.4), satisfactory (0.4<κ<0.6), good (0.6<κ<0.8), and very good (0.8<κ<1) (5). Some studies have used weighted kappa statistics. Because usually only one of these two parameters is reported, the results cannot be directly compared.

Overview of triage instruments

Registration of vital signs alone is not suitable for identification of critically ill patients in the emergency department (10). Therefore various systems are used internationally to determine initial treatment priorities. These range from unstructured classification according to one’s own experience (“best guess” [11]) over instruments such as a three-level “traffic light” system (red: emergency; amber: urgent; green: non-urgent [12]) to four- and five-level scales (13– 16). Some of these instruments are just used at one particular institution, so their dependability is insufficiently documented.

Five-level instruments are significantly correlated with resource utilization, rates of admission for inpatient treatment, duration of emergency treatment, and frequency of transfer to intensive care or mortality (14). Comparison of methods revealed that three-level triage systems have insufficient reliability. The interobserver reliability between triage personnel and experts is low (κ = 0.19 to 0.38 [5]), while that of the five-level system is significantly higher (κ = 0.68; p<0.01 [17]). We will therefore review the literature on established five-level triage systems.

Australasian Triage Scale

The Australasian Triage Scale (ATS) has been employed in all Australian emergency departments since 1994 (7). Each level of priority has a defined time limit within which evaluation by a doctor should begin (Table). The process data from individual hospitals and for different regions are published on the Internet. Findings on the validity or reliability of this instrument are available, although no prospective assessment of reliability has yet been carried out (Box).

Canadian Triage and Acuity Scale

The Canadian Triage and Acuity Scale (CTAS) is based on the ATS and was developed in the 1990s by emergency physicians in New Brunswick, Canada (15). Since 1997 the parameters of the CTAS have been compulsorily documented by the Canadian Institute of Health Information. As in the ATS, the times from arrival to evaluation by a doctor are recorded.

In the CTAS an extensive list of presenting clinical complaints and symptoms is used to determine the triage level. These include anamnestic parameters associated with high risk, e.g., intoxication, together with clinical signs, vital parameters, and symptoms such as shortness of breath or abdominal pain. Triage must be repeated after a defined waiting time or when there is a change in the patient’s symptoms. The validity and reliability of the CTAS are outstanding (Box), and a modified instrument has been developed for evaluation of pediatric emergencies (18). The descriptors and modifiers of the CTAS are encapsulated in a software application (www.caep.ca). In rural areas of Canada the triage is sometimes carried out exclusively by specially trained nurses, who then decide whether patients need to be transferred elsewhere for further medical care.

Manchester Triage System

The Manchester Triage System (MTS) is used in emergency departments in Great Britain and, in a modified translation, in German emergency departments (3, 13). The MTS follows a specific approach: the patient’s principal presenting complaints are allocated to one of 52 flowchart diagrams, e.g., head injury or abdominal pain. Key discriminators are defined for each of these diagrams, such as danger to life, pain, or state of consciousness. When a new patient presents to the emergency department the triage nurse assigns their reported complaints to a defined algorithm and then determines the treatment priority with the aid of fixed rules that take account of vital signs. The few studies that have been performed point to satisfactory reliability of this tool (Box) (19).

Emergency Severity Index

The Emergency Severity Index (ESI) is a five-level triage algorithm that was developed in the USA in the late 1990s (20). Treatment priority is decided on the basis of disease severity and the expected resource needs (Figure 2). The triage algorithm consists of four decision points where the trained triage nurse asks specific questions. First, patients with life-threatening conditions (ESI levels 1 and 2) are identified. Unstable patients are typically assigned to ESI triage level 1, e.g., in the presence of hemodynamic or respiratory instability. Patients with (potentially) life-threatening symptoms, e.g., thoracic pain in acute coronary syndrome or loss of consciousness, and also those with severe pain, psychiatric disorders, or states of intoxication, are assigned to triage level 2. The remaining levels (3 to 5) are defined by the expected resource needs and vital signs (Figure 2). Resources in this sense are services such as X-ray and administration of intravenous medication that go beyond physical examination and are necessary to reach a decision on how to proceed (6). Clinical studies show that this instrument also has good validity and reliability in specific groups of patients such as children and the elderly (Box). A validated translation of this tool into German has been published by a team from the emergency department of the University Hospital Basel, Switzerland (8).

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Figure 2

Triage algorithm of the Emergency Severity Index, version 4. An accompanying brief description of this algorithm (8) supports the members of staff concerned during the triage process. The triage system is explained in detail in the original English handbook (6). At decision point D (danger zone vitals?) there are defined age-dependent thresholds (m, months; y, years) for heart rate (HR) in beats per minute, respiratory rate (RR) in breaths per minute, and oxygen saturation as measured by pulse oximetry (SpO2). If these thresholds are exceeded, the triage nurse may decide to assign the patient to a higher priority level.

Other five-level triage instruments

Regional solutions such as the Gruppo Formazione Triage system in Italy (21), the Taiwan Triage Scale (22), the Cape Triage Scale (23), and the Geneva Emergency Triage Scale (16) have been used, and yet other tools have been employed in individual hospitals. Not all of these systems have been described in journals with external peer review. Since some of these methods draw on the above-mentioned triage instruments and some have not been comprehensively evaluated, they will not be discussed further here.

Evaluation of the triage instruments

The five-level triage scales are superior to three-level systems with regard to validity and reliability (12). Some European societies therefore demand the use of a five-level triage system in emergency departments in which treatment capacity is sometimes exceeded (4). Taking the above-mentioned limitations of methodology into account, the highest numbers of publications refer to the five-level instruments CTAS and ESI, both of which have been the subject of multicenter studies and analyses carried out in Europe. The ATS is also well documented, but published data on the MTS are sparse.

Five-level triage instruments in German

Among the triage instruments described herein, the MTS has been documented in detail in German. In our view, however, problems arise from the fact that the German translation does not make it quite clear why the original algorithm has been modified. For example, there are only 50 instead of 52 flowchart diagrams, the defined reaction times have been changed, and various other modifications, e.g., in evaluation of pain, have been introduced. Moreover, concepts such as “hot adult” and “young pain,” though defined in the book (13), are unaccustomed in German and therefore may constitute sources of error. The MTS is widely used in Germany, but there are no published data on the validity and reliability of the German version.

In the meantime a study has been conducted on the validity and reliability of the German translation of the ESI (8). Initial analyses confirm high validity and reliability of this instrument in German (Grossmann FF et al.: Transporting clinical tools to new settings: cultural adaptation and validation of the Emergency Severity Index in German. Ann Emerg Med 2010; in press). Because the training of nurses varies internationally, one might assume that triage instruments developed in English-speaking countries require modification and adaptation to circ*mstances in Germany. However, our experience with the implementation of the ESI in the emergency departments of Nuremberg Hospital, Germany and the University Hospital Basel, Switzerland shows that this triage instrument can be adopted without modification and safely applied by nursing staff trained in Germany. The systematic data acquired in the course of triage yield information on the severity of illness of patients presenting to German emergency departments (Figure 1); this is important not only for epidemiological purposes but also for health policy and economic analyses and prognoses.

Implementation and quality management

The implementation of a structured triage system in an emergency department is associated with a transitional phase and requires careful planning involving all parties concerned, including the nursing and medical staff. Besides the development of a training program, the consequences for patient flow, the hospital information system, and the workflow of the interprofessional team must be considered. Realistically, a modern triage instrument should be able to be implemented within 9 to 12 months (6). Our own experience shows that any instrument that is implemented has to be regularly evaluated and quality improvement measures developed jointly by the members of the team. Case discussions are suggested (6). Another possibility is practice on an interactive triage simulator, as done at the University Hospital Geneva, Switzerland (16).

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Conflict of interest statement

The authors declare that no conflict of interest exists according to the guidelines of the International Committee of Medical Journal Editors.

1. Pitts SR, Niska RW, Xu J, Burt CW. National Hospital Ambulatory Medical Care Survey: 2006 emergency department summary. Natl Health Stat Report. 2008:1–38. [PubMed] [Google Scholar]

2. Steffen W, Tempka A, Klute G. Falsche Patientenanreize in der Ersten Hilfe der Krankenhäuser. Dtsch Arztebl. 2007;104:1088–1091. [Google Scholar]

3. Schellein O, Ludwig-Pistor F, Bremerich DH. Manchester triage system: Process optimization in the interdisciplinary emergency department. Anaesthesist. 2008;58:163–170. [PubMed] [Google Scholar]

4. Rutschmann OT, Siber RS, Hugli OW. Empfehlung der Schweizerischen Gesellschaft für Notfall- und Rettungsmedizin (SGNOR) zur Triage in Schweizer Notfallstationen. Schweiz Ärztezeitung. 2009;90:1–2. [Google Scholar]

5. Fernandes CM, Tanabe P, Gilboy N, et al. Five-level triage: a report from the ACEP/ENA Five-level Triage Task Force. J Emerg Nurs. 2005;31:39–50. [PubMed] [Google Scholar]

6. Gilboy N, Tanabe P, Travers D, Rosenau AM, Eitel DR. MD: Agency for Healthcare Research and Quality. 05-0046-2 ed. Rockville: AHRQ Publication No; 2005. Emergency Severity Index, Version 4. Implementation Handbook. [Google Scholar]

7. Australasian College for Emergency Medicine. Guidelines on the implementation of the Australasian Triage Scale in emergency departments. www.acem.org.au/infocentre.aspx?docId=59#POLICIES. Accessed on 5 January 2009.

8. Grossmann FF, Delport K, Keller DI. Emergency Severity Index: Deutsche Übersetzung eines validen Triageinstruments. Notfall Rettungsmed. 2009;12:290–292. [Google Scholar]

9. Twomey M, Wallis LA, Myers JE. Limitations in validating emergency department triage scales. Emerg Med J. 2007;24:477–479. [PMC free article] [PubMed] [Google Scholar]

10. Subbe CP, Slater A, Menon D, Gemmell L. Validation of physiological scoring systems in the accident and emergency department. Emerg Med J. 2006;23:841–845. [PMC free article] [PubMed] [Google Scholar]

11. Wuerz R, Fernandes CM, Alarcon J. Inconsistency of emergency department triage. Emergency Department Operations Research Working Group. Ann Emerg Med. 1998;32:431–435. [PubMed] [Google Scholar]

12. Wuerz RC, Milne LW, Eitel DR, Travers D, Gilboy N. Reliability and validity of a new five-level triage instrument. Acad Emerg Med. 2000;7:236–242. [PubMed] [Google Scholar]

13. Mackway-Jones K, Marsden J, Windle J. Das Manchester Triage System. 2nd edition. Bern: Huber; 2006. Ersteinschätzung in der Notaufnahme. [Google Scholar]

14. Tanabe P, Gimbel R, Yarnold PR, Kyriacou DN, Adams JG. Reliability and validity of scores on The Emergency Severity Index version 3. Acad Emerg Med. 2004;11:59–65. [PubMed] [Google Scholar]

15. Bullard MJ, Unger B, Spence J, Grafstein E. Revisions to the Canadian Emergency Department Triage and Acuity Scale (CTAS) adult guidelines. CJEM. 2008;10:136–151. [PubMed] [Google Scholar]

16. Rutschmann OT, Kossovsky M, Geissbuhler A, et al. Interactive triage simulator revealed important variability in both process and outcome of emergency triage. J Clin Epidemiol. 2006;59:615–621. [PubMed] [Google Scholar]

17. Travers DA, Waller AE, Bowling JM, Flowers D, Tintinalli J. Five-level triage system more effective than three-level in tertiary emergency department. J Emerg Nurs. 2002;28:395–400. [PubMed] [Google Scholar]

18. Warren DW, Jarvis A, LeBlanc L, Gravel J. Revisions to the Canadian Triage and Acuity Scale paediatric guidelines (PaedCTAS) CJEM. 2008;10:224–243. [PubMed] [Google Scholar]

19. van Veen M, Steyerberg EW, Ruige M, et al. Manchester triage system in paediatric emergency care: prospective observational study. BMJ. 2008;337 [PMC free article] [PubMed] [Google Scholar]

20. Shelton R. The emergency severity index 5-level triage system. Dimens Crit Care Nurs. 2009;28:9–12. [PubMed] [Google Scholar]

21. Gruppo Formazione Triage. Triage infermieristico. 2nd edition. McGraw-Hill Companies; 2005. [Google Scholar]

22. Chi CH, Huang CM. Comparison of the Emergency Severity Index (ESI) and the Taiwan Triage System in predicting resource utilization. J Formos Med Assoc. 2006;105:617–625. [PubMed] [Google Scholar]

23. Bruijns SR, Wallis LA, Burch VC. A prospective evaluation of the Cape triage score in the emergency department of an urban public hospital in South Africa. Emerg Med J. 2008;25:398–402. [PubMed] [Google Scholar]

24. Richardson JR, Braitberg G, Yeoh MJ. Multidisciplinary assessment at triage: a new way forward. Emerg Med Australas. 2004;16:41–46. [PubMed] [Google Scholar]

25. Cooke MW, Jinks S. Does the Manchester triage system detect the critically ill? J Accid Emerg Med. 1999;16:179–181. [PMC free article] [PubMed] [Google Scholar]

e1. Cooke MW, Jinks S. Does the Manchester triage system detect the critically ill? J Accid Emerg Med. 1999;16:179–181. [PMC free article] [PubMed] [Google Scholar]

e2. Goodacre SW, Gillett M, Harris RD, Houlihan KP. Consistency of retrospective triage decisions as a standardised instrument for audit. J Accid Emerg Med. 1999;16:322–324. [PMC free article] [PubMed] [Google Scholar]

e3. Speake D, Teece S, Mackway-Jones K. Detecting high-risk patients with chest pain. Emerg Nurse. 2003;11:19–21. [PubMed] [Google Scholar]

e4. Roukema J, Steyerberg EW, van Meurs A, Ruige M, van der Lei J, Moll HA. Validity of the Manchester triage system in paediatric emergency care. Emerg Med J. 2006;23:906–910. [PMC free article] [PubMed] [Google Scholar]

e5. van Veen M, Steyerberg EW, Ruige M, et al. Manchester triage system in paediatric emergency care: prospective observational study. BMJ. 2008;337 [PMC free article] [PubMed] [Google Scholar]

e6. van der Wulp I, van Baar ME, Schrijvers AJ. Reliability and validity of the Manchester triage system in a general emergency department patient population in the Netherlands: results of a simulation study. Emerg Med J. 2008;25:431–434. [PubMed] [Google Scholar]

e7. Jelinek G, Little M. Inter-rater reliability of the national triage scale: over 11’500 simulated occasions of triage. Emerg Med. 1996;8:226–230. [Google Scholar]

e8. Dilley S, Standen P. Victorian nurses demonstrate concordance in the application of the national triage scale. Emerg Med. 1998;10:12–18. [Google Scholar]

e9. Van Gerven R, Delooz H, Sermeus W. Systematic triage in the emergency department using the Australian national triage scale: a pilot project. Eur J Emerg Med. 2001;8:3–7. [PubMed] [Google Scholar]

e10. Doherty SR, Hore CT, Curran SW. Inpatient mortality as related to triage category in three New South Wales regional base hospitals. Emerg Med (Fremantle) 2003;15:334–340. [PubMed] [Google Scholar]

e11. Considine J, LeVasseur SA, Villanueva E. The Australasian triage scale: examining emergency department nurses’ performance using computer and paper scenarios. Ann Emerg Med. 2004;44:516–523. [PubMed] [Google Scholar]

e12. Creaton A, Liew D, Knott J, Wright M. Interrater reliability of the Australasian triage scale for mental health patients. Emerg Med Australas. 2008;20:468–474. [PubMed] [Google Scholar]

e13. Beveridge R, Ducharme J, Janes L, Beaulieu S, Walter S. Reliability of the Canadian emergency department triage and acuity scale: interrater agreement. Ann Emerg Med. 1999;34:155–159. [PubMed] [Google Scholar]

e14. 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. [PubMed] [Google Scholar]

e15. Worster A, Gilboy N, Fernandes CM, et al. Assessment of inter-observer reliability of two five-level triage and acuity scales: a randomized controlled trial. CJEM. 2004;6:240–245. [PubMed] [Google Scholar]

e16. Grafstein E, Innes G, Westman J, Christenson J, Thorne A. Inter-rater reliability of a computerized presenting-complaint-linked triage system in an urban emergency department. CJEM. 2003;5:323–329. [PubMed] [Google Scholar]

e17. Jimenez JG, Murray MJ, 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. [PubMed] [Google Scholar]

e18. Goransson K, Ehrenberg A, Marklund B, Ehnfors M. Accuracy and concordance of nurses in emergency department triage. Scand J Caring Sci. 2005;19:432–438. [PubMed] [Google Scholar]

e19. Dong SL, Bullard MJ, Meurer DP, et al. Predictive validity of a computerized emergency triage tool. Acad Emerg Med. 2007;14:16–21. [PubMed] [Google Scholar]

e20. Dong SL, Bullard MJ, Meurer DP, Blitz S, Holroyd BR, Rowe BH. The effect of training on nurse agreement using an electronic triage system. CJEM. 2007;9:260–266. [PubMed] [Google Scholar]

e21. Bergeron S, Gouin S, Bailey B, Amre DK, Patel H. Agreement among pediatric health care professionals with the pediatric Canadian triage and acuity scale guidelines. Pediatr Emerg Care. 2004;20:514–518. [PubMed] [Google Scholar]

e22. Gravel J, Gouin S, Bailey B, Roy M, Bergeron S, Amre D. Reliability of a computerized version of the pediatric Canadian triage and acuity scale. Acad Emerg Med. 2007;14:864–869. [PubMed] [Google Scholar]

e23. Ma W, Gafni A, Goldman RD. Correlation of the Canadian pediatric emergency triage and acuity scale to ED resource utilization. Am J Emerg Med. 2008;26:893–897. [PubMed] [Google Scholar]

e24. Gravel J, Gouin S, Manzano S, Arsenault M, Amre D. Interrater agreement between nurses for the pediatric Canadian triage and acuity scale in a tertiary care center. Acad Emerg Med. 2008;15:1262–1267. [PubMed] [Google Scholar]

e25. Wuerz RC, Milne LW, Eitel DR, Travers D, Gilboy N. Reliability and validity of a new five-level triage instrument. Acad Emerg Med. 2000;7:236–242. [PubMed] [Google Scholar]

e26. Wuerz RC, Travers D, Gilboy N, Eitel DR, Rosenau A, Yazhari R. Implementation and refinement of the emergency severity index. Acad Emerg Med. 2001;8:170–176. [PubMed] [Google Scholar]

e27. Wuerz R. Emergency severity index triage category is associated with six-month survival. ESI triage study group. Acad Emerg Med. 2001;8:61–64. [PubMed] [Google Scholar]

e28. Travers DA, Waller AE, Bowling JM, Flowers D, Tintinalli J. Five-level triage system more effective than three-level in tertiary emergency department. J Emerg Nurs. 2002;28:395–400. [PubMed] [Google Scholar]

e29. Eitel DR, Travers DA, Rosenau AM, Gilboy N, Wuerz RC. The emergency severity index triage algorithm version 2 is reliable and valid. Acad Emerg Med. 2003;10:1070–1080. [PubMed] [Google Scholar]

e30. Tanabe P, Gimbel R, Yarnold PR, Kyriacou DN, Adams JG. Reliability and validity of scores on The emergency severity index version 3. Acad Emerg Med. 2004;11:59–65. [PubMed] [Google Scholar]

e31. Tanabe P, Gimbel R, Yarnold PR, Adams JG. The emergency severity index (version 3) 5-level triage system scores predict ED resource consumption. J Emerg Nurs. 2004;30:22–29. [PubMed] [Google Scholar]

e32. Baumann MR, Strout TD. Evaluation of the emergency severity index (version 3) triage algorithm in pediatric patients. Acad Emerg Med. 2005;12:219–224. [PubMed] [Google Scholar]

e33. Chi CH, Huang CM. Comparison of the emergency severity index (ESI) and the Taiwan triage system in predicting resource utilization. J Formos Med Assoc. 2006;105:617–625. [PubMed] [Google Scholar]

e34. Worster A, Fernandes CM, Eva K, Upadhye S. Predictive validity comparison of two five-level triage acuity scales. Eur J Emerg Med. 2007;14:188–192. [PubMed] [Google Scholar]

e35. Baumann MR, Strout TD. Triage of geriatric patients in the emergency department: validity and survival with the emergency severity index. Ann Emerg Med. 2007;49:234–240. [PubMed] [Google Scholar]

e36. Elshove-Bolk J, Mencl F, van Rijswijck BT, Simons MP, van Vugt AB. Validation of the emergency severity index (ESI) in self-referred patients in a European emergency department. Emerg Med J. 2007;24:170–174. [PMC free article] [PubMed] [Google Scholar]