Abstract
Introduction
The American College of Surgeons (ACS) delineates trauma team activation (TTA) criteria to identify seriously injured trauma patients in the field. Patients are deemed to be severely undertriaged (SU), placing them at risk for adverse outcomes, when they do not meet TTA criteria but nonetheless sustain significant injuries (Injury Severity Score [ISS] ≥25).
Objectives
Delineate patient demographics, injuries, and outcomes after SU.
Participants
Trauma patients presenting to our ACS-verified Level 1 trauma center with ISS ≥25 were included (11/2015-03/2022). Transfers and private vehicle transports were excluded. Patients were dichotomized and compared by trauma arrival level: TTA (Appropriately Triaged, AT) vs routine consults (SU).
Results
Study criteria were satisfied by 1653 patients: 1375 (83%) AT and 278 (17%) SU. Severely undertriaged patients were older than AT patients (47 vs 36 years, P < .001). Severely undertriaged occurred almost exclusively following blunt trauma (96% vs 71%, P < .001). Injury Severity Score was lower following SU than AT (29 vs 32, P < .001). The most common severe injuries (Abbreviated Injury Scale score [AIS] ≥3) among the SU group were in the Chest (n = 179, 64%). Severely undertriaged patients necessitated emergent intubation (n = 34, 12%), surgery (n = 59, 21%), and angioembolization (n = 22, 8%) at high rates. Severely undertriaged mortality was n = 40, 14%.
Conclusion
Severely undertriaged occurred among a substantial proportion of ISS ≥25 patients, predominately following blunt trauma. Severe chest injuries were most likely to evade capture. Rates of intubation, emergent intervention, and in-hospital mortality were high after SU. Efforts should be made to identify such patients in the field as they may benefit from TTA.
Keywords
Introduction
The American College of Surgeons Committee on Trauma (ACS COT) delineates trauma team activation (TTA) criteria, which allow for field identification of the sickest trauma patients. 1 Appropriate hospital triage ensures patients with major trauma receive early mobilization of necessary personnel and resources while also preventing misallocation of these finite resources to patients who do not need them. When patients with major trauma, defined as an Injury Severity Score (ISS) > 15, do not meet TTA criteria, they are termed undertriaged and are at risk for adverse outcomes and mortality.2,3 It is unclear what impact undertriage has on severely injured patients (ISS ≥25) who evade current TTA criteria. These patients are termed the severely undertriaged (SU) and theoretically are at further risk for adverse outcomes due to the magnitude of their traumatic injuries. The study objective was to compare SU patients to similarly injured patients who met TTA criteria (defined as the Appropriately Triaged, AT) in order to identify any impact on outcomes from severe undertriage.
Methods
From November 1, 2015, to March 31, 2022, all trauma patients presenting to our ACS-verified Level I trauma center were screened for inclusion in this retrospective observational study. Institutional review board approval was sought and granted with a waiver of informed consent. Patients with ISS ≥25 were included. Transfers and private vehicle transports were excluded. Compliance with TTA criteria was 100% and there were no patients meeting TTA criteria who failed to be activated appropriately.
Patients demographics (age, sex); clinical data (prehospital and first Emergency Department [ED] vital signs); injury data (mechanism of injury, ISS, Abbreviated Injury Scale [AIS] score by body region); and outcomes were collected. When the mechanism of injury was a fall, this included both ground level falls and falls from height. Outcomes included need for emergent intervention, defined by patient transfer directly from the ED to the operating room (OR) or interventional radiology (IR) suite; intubation in the ED; blood transfusion; hospital length of stay (LOS, in days); intensive care unit LOS; and in-hospital mortality.
The standard ACS COT TTA criteria 1 are systolic blood pressure <90 mmHg; gunshot wound to the neck, torso, or extremities proximal to the elbow and knee; Glasgow Coma Scale (GCS) score <9; patients with respiratory compromise, including those intubated on scene; transferred patients who are receiving blood products; and any trauma patient deemed to potentially benefit from prehospital TTA as determined by the Emergency Medicine provider’s discretion. 3 At our institution, we use a modified set of TTA criteria (mTTA) in which age over 70 years with traumatic mechanism other than ground level falls is added to the ACS COT TTA criteria. This is a result of previous work demonstrating an increased risk of morbidity and mortality among older adult trauma patients.4-6
Our institution has two levels of trauma arrivals: patients who trigger mTTA and those who do not, termed routine consults. Routine consult patients do not arrive as mTTAs and are assessed by Emergency Medicine with consultation to Trauma Surgery and other services as needed. Patients were dichotomized into study groups based on level of trauma arrival: AT patients, who arrived after meeting mTTA criteria; and SU patients, who did not meet mTTA criteria and were routine consults. Appropriateness of hospital triage was thereby assessed using the Cribari matrix 1 , based on ISS and level of trauma arrival. In this way, SU was defined as patients who did not meet TTA criteria but had an ISS of ≥25. AT was defined as patients who met TTA criteria and had an ISS of ≥25.
Descriptive statistics were used to summarize the patients’ demographics, injury data, clinical data, and outcomes. Continuous variables are presented as median (interquartile range [IQR]) and categorical variables as numbers (percentages). Bivariable analysis compared demographics, clinical and injury data, and outcomes between groups using the Mann-Whitney U test, Student’s T-test, chi square (χ2) test, and Fisher’s exact test as appropriate. Statistical significance was defined as P < .05.
Results
During the study, 16,182 trauma patients presented to our center. Of these, 1761 (11%) had an ISS of ≥25 and were included in the study (Figure 1). After exclusion of 85 transfers (<1%) and 23 private vehicle transports (<1%), 1653 patients satisfying study criteria remained and were analyzed. Among the study patients, 1375 (83%) were AT patients and 278 (17%) were SU. Flow of patients through Study. ACS, American College of Surgeons. ISS, Injury Severity Score.
Patient Demographics, Clinical Data, and Injury Data.
Continuous variables presented as median [interquartile range]. Categorical variables presented as number (percentage).
Abbreviations: TTA, trauma team activation. ED, emergency department. SBP, systolic blood pressure in mmHg. HR, heart rate in beats per minute. GCS, Glasgow Coma Scale score. AVP, auto vs pedestrian. MVC, motor vehicle crash. MCC, motorcycle crash. GSW, gunshot wounds. SW, stab wounds. ISS, Injury Severity Score. AIS, Abbreviated Injury Scale score.
Outcomes.
Continuous Variables Present as Median [Interquartile Range].
Categorical variables presented as number (percentage).
Abbreviations: TTA, trauma team activation. ED, emergency department. OR, operative room. IR, interventional radiology. LOS, length of stay. ICU, intensive care unit.
aTransfusion volumes in cc.
Discussion
Accurate hospital triage is a fundamental quality metric for trauma systems. The ACS COT TTA criteria must be both comprehensive and succinct to be useful in the prehospital environment, which is extraordinarily difficult if not impossible to achieve. Therefore, there are some patients who evade capture by the current TTA system but still stand to benefit from full activation of the trauma team, including the early mobilization of resources that may be needed such as the blood bank or operating room. Such patients are referred to as undertriaged, and the COT defines an undertriage rate of less than 5% as the accepted goal for high quality systems.
While the undertriaged (ISS >15) have now been studied to some extent, little work has been done to focus on the SU (ISS ≥25). Conceptually, one would expect these patients to be at highest risk for morbidity or mortality after being undertriaged due to the severe nature of their injuries. In our study, SU occurred among a substantial proportion of ISS ≥25 patients and almost exclusively following blunt trauma. Severe chest injuries were most likely to evade capture by current TTA criteria. Despite not meeting TTA criteria, the severely undertriaged necessitated emergent intubation, surgical intervention, and angioembolization at substantial rates. Perhaps most strikingly, despite not meeting TTA criteria, the severely undertriaged still experienced an in-hospital mortality rate of 14%.
The severely undertriaged had improved outcomes as compared to appropriately triaged patients. This is intuitive as the appropriately triaged patients who met standard TTA criteria were likely to have sustained greater physiologic disturbances prior to arrival to our trauma center by virtue of their manifestation of field hypotension or comatose status, for example. Regardless, given the high rates of need for emergent intervention in the severely undertriaged, it is likely that these patients would still benefit from the prehospital mobilization of trauma personnel and resources that accompany TTA.
The most important question that arises from this work is how to better capture the severely injured patients who do not meet standard ACS COT TTA criteria. Because severe chest trauma was most likely to evade capture by current TTA criteria, the development of a better framework for EMS providers to identify injuries such as chest injuries that are externally occult may be warranted. 7 This may feasibly include the integration of pulse oximetry values into field TTA criteria, but this is speculative. It should also be noted that although severe chest trauma was most likely to evade capture, this was closely followed by severe head and abdominopelvic trauma. Furthermore, we did not examine the need for emergent intervention specifically among undertriaged patients with severe chest trauma and therefore the true mitigated harm from having these patients arrive as TTAs is unclear. Further study is necessary.
Much work has been done to identify factors to improve triage fidelity. One factor that is well documented to affect COT triage criteria validity is age.4,6 The geriatric cohort of patients is much more likely to have underlying medical conditions that affect their physiologic reserve and to be treated with medications that mask derangement of physiologic parameters.5,8 As such, age greater than 70 has been a part of the modified TTA criteria at our institution for many years.
Given the variety of factors influencing triage decisions, a number of other metrics have been investigated. Patients who have only mild-moderate perturbations in GCS but nonetheless have a TBI are at particularly high risk for adverse outcomes after undertriage. 9 As such, it has been suggested that a higher GCS cut-off score (eg <12 instead of the current < 9) may be a prudent adjustment to current TTA criteria to allow for better capture of these patients without a dramatic increase in overtriage. 9 The risk for poor outcomes among this group may be related to the delayed time to investigations, such as computed tomography scan of the head, and/or resultant delayed time to neurosurgical intervention.10,11
Pulse pressure is an additional metric that may allow for the prehospital identification of patients who are otherwise stable but still stand to benefit from early mobilization of trauma center personnel and resources. Narrow pulse pressure in the field has been shown to indicate the likelihood of significant hemorrhage 12 and predicts the need for massive transfusion 13 and emergent intervention 14 in otherwise stable trauma patients. Other suggested potential metrics to improve triage fidelity include prehospital lactate 15 and shock index. 16
Another potentially problematic aspect of the appropriateness of hospital triage must be emphasized. The appropriateness of hospital trauma triage, as delineated by the ACS COT, is currently quantified with the ISS via the Cribari matrix method. 1 While in many ways the ISS is a useful metric to quantify injury severity, for example for research and communication purposes, it is limited in its ability to retrospectively analyze the fidelity of triage decisions, especially given its strictly post-hoc application.17,18 The ISS is also particularly limited in its ability to quantify severity of penetrating injury, as the system cannot account for the compounded severity of a projectile damaging multiple organs within a single body region. Newer triage accuracy scoring systems such as the Need for Trauma Intervention (NFTI) 19 and the Need for Emergent Intervention within 6 hours (NEI-6) 20 are credited for better reflecting the need for early mobilization of trauma center resources and personnel. Therefore, these systems may be better tools to use in the future to assess the accuracy of trauma triage.
This study was limited by its construction as a single center retrospective cohort study. In particular, our use of an age modification to the ACS COT TTA criteria limits generalizability of our data. While this is an important modifier to prevent undertriage,4,6 TTA of all patients aged >70 with traumatic mechanism of injury other than ground level falls is not universally adopted among trauma centers. The generalizability of our findings to centers that do not apply this modification is therefore unclear. Further study of this topic will be important.
While our SU cohort fared better than the AT patients of similar severity in many respects, these data demonstrate that they are still at risk for poor outcomes, and as such, developing novel ways to identify these patients in the field should be a priority. One future direction of this research should include methods to improve the prehospital evaluation for the presence of severe chest trauma. Additionally, analysis of SU patients with novel scoring criteria such as NFTI and NEI-6 may help to identify the subset that stands to benefit the most from early mobilization of trauma personnel and resources. Developing strategies to identify the SU cohort on a prehospital basis will be an important goal moving forward in order to continue to strive towards the optimal care of all injured patients.
Footnotes
Author Contributions
KA and MS provided the study concept. KA, LD, and MDW performed the data collection. MS and NO completed the data analysis. KA, MS, RM, and DD performed the data interpretation. All authors participated in writing and critically reviewing the final manuscript.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Presentations
Accepted for presentation (plenary session oral presentation) at the Annual Scientific Meeting of the Southern California Chapter of the American College of Surgeons (ACS) on January 20-22, 2023 in Santa Barbara, CA.