2.4 Field Triage Rate

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Description of Indicator

Relationship to Quality  Medical care should be efficient and effective 
Type of Indicator Prehospital and Hospital process, System level
Proposed Data Source Trauma Registries OR Administrative Data
Definition Patients with major anatomic injuries admitted to a hospital without the resources to manage the patient's injuries per 100 patients
Numerator All pagients* age 18 years and older diagnosed with major anatomic injuries AND admitted to a hospital within the trauma system ‡ that is not a Level 1 OR Level 2 trauma center
Denominator All patients* age 18 years and older diagnosed with major anatomic injuries AND admitted to a hospital within the trauma system
Benchmark Under triage rate < 5%†
Risk Adjustment Not applicable

* Field triage criteria for injured patients are evolving. We propose currently using recommendations from an expert panel on field triage published by the CDC9,10, but restricting criteria to major anatomic injury diagnoses (excluding physiological variables, e.g. blood pressure) to facilitate the use of trauma registry or administrative data for measurement purposes.
‡ Includes all acute care hospitals within the geographical area and/or operational boundaries of an inclusive trauma system.

† American College of Surgeons Committee on Trauma has proposed that under triage rates can be as high as 5% and over triage rates range between 25% and 50%2. These benchmarks were proposed using different methods of calculation. We propose using the American College of Surgeons Committee on Trauma benchmark of <5% for under triage in order to make the measure sensitive for identifying patients with major anatomic injuries that may benefit from admission to a Level 1 or Level 2 trauma center.
Inclusion criteria for patients with major anatomic injuries likely to benefit from admission to a Level 1 OR Level 2 trauma center are (satisfying any criterion is sufficient):

Penetrating injury to head, neck, torso extremities (proximal to elbow or knee)
Flail chest
> 2 proximal long-bone fractures
Crush, degloved or mangled extremity
Amputation proximal to wrist and ankle
Pelvic fracture
Open or depressed skull fracture


Treatment of injured patients in the prehospital setting should include rapid transport to the closest appropriate facility. Under triage is defined as a triage decision that classifies patients as not needing trauma center care when in fact they are likely to benefit from this level of care (false negative triage)2. Over triage is the decision that incorrectly classifies a patient as needing trauma center care when in fact they are unlikely to benefit from this level of care (false positive triage)2.
The indicator has been constructed to complement quality indicator #1 (Protocol of Field Triage) and quality indicator #7 (Time to Definitive Trauma Center). It is intended to monitor rates of patients with major anatomic injuries admitted to hospitals without the resources to manage the patients’ injuries and not to evaluate the initial destination hospital of EMS transports. We selected this approach to allow prehospital transport algorithms to include initial transport of severely injured patients to the closest facility for the purposes of facilitating transport to a Level 1 or Level 2 trauma center.


Panel Review
Panelists emphasized that field triage is an important measure of the coordination of prehospital and hospital care and determines whether patients are receiving care in the most appropriate setting. Panelists suggested EMS, trauma registry and/or administrative data as possible data sources for this indicator.
Panelists discussed the challenges of data collection relating to this indicator as it may potentially involve multiple regions and data sources. In rural areas this indicator may be dependent on what type of hospital (trauma classification) is available, as Level 1 or 2 trauma centers may be a long distance away. Panelists noted that this indicator would work well in urban areas with multiple types of healthcare facilities.
Panelists indicated that ideally both under and over triage would be calculated and examined given the potential impact of both on patient care and trauma system efficiency. It was also noted that examining over triage may not be practical as it is likely dependent on local protocols, which depict what patients go to what hospitals.


Trauma Center Review
The trauma centers reported that this indicator was crucial for assessing system performance. Specifically, they indicated that it allows for evaluation of how well EMS personnel are performing in relation to the triage protocol and assesses global performance of the triage protocol. Concerns from the trauma centers reflected the panelists’ discussion that data collection may be difficult. They noted that considerations for geographical area, anatomic and physiological criteria and mechanism of injury need to be included. The trauma centers stressed the need for all centers to be compliant in documentation of both under and over triage. They highlighted that in order for the indicator to be accurate, information must be available for all injured patients transported to hospitals (trauma centers and non-trauma centers).


Review of Literature & Evidence
Face Validity: In one study, 95% of Delphi panel participants ranked monitoring under triage and identifying causes as very important13.
Construct Validity: No studies identified.
Reliability: No studies identified.
Risk Adjustment: Eight variables for risk adjustment have been used in the literature to examine this indicator: gender, race, age, GCS at scene, ISS, mechanism of injury, type of injuries and provider level (type)25,26,27,28,29. However, it is unclear that risk adjustment should be used when measuring processes of care.
Utilization: Measures of under triage rate are used as an indicator by a moderate number of trauma centers: USA 31% (61/200), Canada 3% (1/35), Australasia 0% (0/12).


This indicator is a combination of two indicators evaluated by the Quality Indicators in Trauma Care Consensus Panel: Under Triage and Severely Injured Patients Admitted to Non-Trauma Center. Rosengart et al. developed the indicator using a Delphi panel of trauma experts13. A national expert panel convened by the CDC in the United States proposed a triage scheme9,10.


2. American College of Surgeons Committee on Trauma. Resources for Optimal Care of the Injured Patient 2006. Chicago: American College of Surgeons; 2006.
9. Centers for Disease Control and Prevention (CDC). CDC - Injury Prevention and Control: Field Triage - Guidelines for the Field Triage of Injured Patients. 2011; http://www.cdc.gov/fieldtriage/index.html. Accessed July 8, 2012.
10. Sasser SM, Hunt RC, Sullivent EE, et al. Guidelines for field triage of injured patients. Recommendations of the National Expert Panel on Field Triage. MMWR Recomm Rep. 2009;58(RR-1):1-35.
13. Rosengart MR, Nathens AB, Schiff MA. The identification of criteria to evaluate prehospital trauma care using the Delphi technique. J Trauma. 2007;62(3):708-713.
25. Caterino JM, Valasek T, Werman HA. Identification of an age cutoff for increased mortality in patients with elderly trauma. Am J Emerg Med. 2010;28(2):151-158.
26. Chang DC, Bass RR, Cornwell EE, Mackenzie EJ. Undertriage of elderly trauma patients to state-designated trauma centers. Arch Surg. 2008;143(8):776-781.
27. Lane P, Sorondo B, Kelly JJ. Geriatric trauma patients-are they receiving trauma center care? Acad Emerg Med. 2003;10(3):244-250.
28. Meldon SW, Reilly M, Drew BL, Mancuso C, Fallon W, Jr. Trauma in the very elderly: a community-based study of outcomes at trauma and nontrauma centers. J Trauma. 2002;52(1):79-84.
29. Haas B, Gomez D, Zagorski B, Stukel TA, Rubenfeld GD, Nathens AB. Survival of the fittest: the hidden cost of undertriage of major trauma. J Am Coll Surg. 2010;211(6):804-811.