The trade-offs in field trauma triage: a multiregion assessment of accuracy metrics and volume shifts associated with different triage strategies

A comparison of performance between a deep learning model with residents for localization and classification of intracranial hemorrhage

Intracranial hemorrhage (ICH) from traumatic brain injury (TBI) requires prompt radiological investigation and recognition by physicians. Computed tomography (CT) scanning is the investigation of choice for TBI and has become increasingly utilized under the shortage of trained radiology personnel. It is anticipated that deep learning models will be a promising solution for the generation of timely and accurate radiology reports. Our study examines the diagnostic performance of a deep learning model and compares the performance of that with detection, localization and classification of traumatic ICHs involving radiology, emergency medicine, and neurosurgery residents. Our results demonstrate that the high level of accuracy achieved by the deep learning model, (0.89), outperforms the residents with regard to sensitivity (0.82) but still lacks behind in specificity (0.90). Overall, our study suggests that the deep learning model may serve as a potential screening tool aiding the interpretation of head CT scans among traumatic brain injury patients.

Mechanism of injury and special considerations as predictive of serious injury: A systematic review

OBJECTIVES

The Centers for Disease Control and Prevention's field triage guidelines (FTG) are routinely used by emergency medical services personnel for triaging injured patients. The most recent (2011) FTG contains physiologic, anatomic, mechanism, and special consideration steps. Our objective was to systematically review the criteria in the mechanism and special consideration steps that might be predictive of serious injury or need for a trauma center.

METHODS

We conducted a systematic review of the predictive utility of mechanism and special consideration criteria for predicting serious injury. A research librarian searched in Ovid Medline, EMBASE, and the Cochrane databases for studies published between January 2011 and February 2021. Eligible studies were identified using a priori inclusion and exclusion criteria. Studies were excluded if they lacked an outcome for serious injury, such as measures of resource use, injury severity scores, mortality, or composite measures using a combination of outcomes. Given the heterogeneity in populations, measures, and outcomes, results were synthesized qualitatively focusing on positive likelihood ratios (LR+) whenever these could be calculated from presented data or adjusted odds ratios (aOR).

RESULTS

We reviewed 2418 abstracts and 315 full-text publications and identified 42 relevant studies. The factors most predictive of serious injury across multiple studies were death in the same vehicle (LR+ 2.2-7.4), ejection (aOR 3.2-266.2), extrication (LR+ 1.1-6.6), lack of seat belt use (aOR 4.4-11.3), high speeds (aOR 2.0-2.9), concerning crash variables identified by vehicle telemetry systems (LR+ 4.7-22.2), falls from height (LR+ 2.4-5.9), and axial load or diving (aOR 2.5-17.6). Minor or inconsistent predictors of serious injury were vehicle intrusion (LR+ 0.8-7.2), cardiopulmonary or neurologic comorbidities (LR+ 0.8-3.1), older age (LR+ 0.6-6.8), or anticoagulant use (LR+ 1.1-1.8).

CONCLUSIONS

Select mechanism and special consideration criteria contribute positively to appropriate field triage of potentially injured patients.

An economic evaluation of triage tools for patients with suspected severe injuries in England

BACKGROUND

Many health care systems triage injured patients to major trauma centres (MTCs) or local hospitals by using triage tools and paramedic judgement. Triage tools are typically assessed by whether patients with an Injury Severity Score (ISS) ≥ 16 go to an MTC and whether patients with an ISS < 16 are sent to their local hospital. There is a trade-off between sensitivity and specificity of triage tools, with the optimal balance being unknown. We conducted an economic evaluation of major trauma triage tools to identify which tool would be considered cost-effective by UK decision makers.

METHODS

A patient-level, probabilistic, mathematical model of a UK major trauma system was developed. Patients with an ISS ≥ 16 who were only treated at local hospitals had worse outcomes compared to being treated in an MTC. Nine empirically derived triage tools, from a previous study, were examined so we assessed triage tools with realistic trade-offs between triage tool sensitivity and specificity. Lifetime costs, lifetime quality adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) were calculated for each tool and compared to maximum acceptable ICERs (MAICERs) in England.

RESULTS

Four tools had ICERs within the normal range of MAICERs used by English decision makers (£20,000 to £30,000 per QALY gained). A low sensitivity (28.4%) and high specificity (88.6%) would be cost-effective at the lower end of this range while higher sensitivity (87.5%) and lower specificity (62.8%) was cost-effective towards the upper end of this range. These results were sensitive to the cost of MTC admissions and whether MTCs had a benefit for patients with an ISS between 9 and 15.

CONCLUSIONS

The cost-effective triage tool depends on the English decision maker's MAICER for this health problem. In the usual range of MAICERs, cost-effective prehospital trauma triage involves clinically suboptimal sensitivity, with a proportion of seriously injured patients (at least 10%) being initially transported to local hospitals. High sensitivity trauma triage requires development of more accurate decision rules; research to establish if patients with an ISS between 9 and 15 benefit from MTCs; or, inefficient use of health care resources to manage patients with less serious injuries at MTCs.

ISS alone, is not sufficient to correctly assign patients post hoc to trauma team requirement

Purpose

An injury severity score (ISS) ≥ 16 alone, is commonly used post hoc to define the correct activation of a trauma team. However, abnormal vital functions and the requirement of life-saving procedures may also have a role in defining trauma team requirement post hoc. The aim of this study was to describe their prevalence and mortality in severely injured patients and to estimate their potential additional value in the definition of trauma team requirement as compared to the definition based on ISS alone.

Methods

Retrospective analysis of a trauma registry including patients with trauma team activation from the years 2009 until 2015, who were 16 years of age or older and were brought to the trauma center directly from the scene. Patients were divided into a group with an ISS ≥ 16 vs. ISS < 16. For analysis a predefined list of abnormal vital functions and life-saving interventions was used.

Results

58,723 patients were included in the study (N = 32,653 with ISS ≥ 16; N = 26,070 with ISS < 16). From the total number of patients that required life-saving procedures or presented with abnormal vital functions 29.1% were found in the ISS < 16 group. From the ISS < 16 group, 36.7% of patients required life-saving procedures or presented with abnormal vital signs. The mortality of those was 8.1%.

Conclusions

Defining the true requirement of trauma team activation post hoc by using ISS ≥ 16 alone does miss a considerable number of subjects who require life-saving interventions or present with abnormal vital functions. Therefore, life-saving interventions and abnormal vital functions should be included in the definitions for trauma team requirement. Further studies have to evaluate, which life-saving procedures and abnormal vital functions are most relevant.

Comorbidities, anticoagulants, and geriatric-specific physiology for the field triage of injured older adults

BACKGROUND

Comorbid conditions and anticoagulants have been considered as field triage criteria to raise the sensitivity for identifying seriously injured older adults, but research is sparse. We evaluated the utility of comorbidities, anticoagulant use, and geriatric-specific physiologic measures to improve the sensitivity of the field triage guidelines for high-risk older adults in the out-of-hospital setting.

METHODS

This was a cohort study of injured adults 65 years or older transported by 44 emergency medical services agencies to 51 trauma and nontrauma hospitals in seven Oregon and Washington counties from January 1, 2011, to December 31, 2011. Out-of-hospital predictors included current field triage criteria, 13 comorbidities, preinjury anticoagulant use, and previously developed geriatric specific physiologic measures. The primary outcome (high-risk patients) was Injury Severity Score of 16 or greater or need for major nonorthopedic surgical intervention. We used binary recursive partitioning to develop a clinical decision rule with a target sensitivity of 95% or greater.

RESULTS

There were 5,021 older adults, of which 320 (6.4%) had Injury Severity Score of 16 or greater or required major nonorthopedic surgery. Of the 2,639 patients with preinjury medication history available, 400 (15.2%) were taking an anticoagulant. Current field triage practices were 36.6% sensitive (95% confidence interval [CI], 31.2%-42.0%) and 90.1% specific (95% CI, 89.2%-91.0%) for high-risk patients. Recursive partitioning identified (in order): any current field triage criteria, Glasgow Coma Scale score of 14 or less, geriatric-specific vital signs, and comorbidity count of 2 or more. Anticoagulant use was not identified as a predictor variable. The new criteria were 90.3% sensitive (95% CI, 86.8%-93.7%) and 17.0% specific (95% CI, 15.8%-18.1%).

CONCLUSIONS

The current field triage guidelines have poor sensitivity for high-risk older adults. Adding comorbidity information and geriatric-specific physiologic measures improved sensitivity, with a decrement in specificity.

LEVEL OF EVIDENCE

Prognostic/Epidemiologic, level II.

Using machine-learning risk prediction models to triage the acuity of undifferentiated patients entering the emergency care system: a systematic review

BACKGROUND

The primary objective of this review is to assess the accuracy of machine learning methods in their application of triaging the acuity of patients presenting in the Emergency Care System (ECS). The population are patients that have contacted the ambulance service or turned up at the Emergency Department. The index test is a machine-learning algorithm that aims to stratify the acuity of incoming patients at initial triage. This is in comparison to either an existing decision support tool, clinical opinion or in the absence of these, no comparator. The outcome of this review is the calibration, discrimination and classification statistics.

METHODS

Only derivation studies (with or without internal validation) were included. MEDLINE, CINAHL, PubMed and the grey literature were searched on the 14th December 2019. Risk of bias was assessed using the PROBAST tool and data was extracted using the CHARMS checklist. Discrimination (C-statistic) was a commonly reported model performance measure and therefore these statistics were represented as a range within each machine learning method. The majority of studies had poorly reported outcomes and thus a narrative synthesis of results was performed.

RESULTS

There was a total of 92 models (from 25 studies) included in the review. There were two main triage outcomes: hospitalisation (56 models), and critical care need (25 models). For hospitalisation, neural networks and tree-based methods both had a median C-statistic of 0.81 (IQR 0.80-0.84, 0.79-0.82). Logistic regression had a median C-statistic of 0.80 (0.74-0.83). For critical care need, neural networks had a median C-statistic of 0.89 (0.86-0.91), tree based 0.85 (0.84-0.88), and logistic regression 0.83 (0.79-0.84).

CONCLUSIONS

Machine-learning methods appear accurate in triaging undifferentiated patients entering the Emergency Care System. There was no clear benefit of using one technique over another; however, models derived by logistic regression were more transparent in reporting model performance. Future studies should adhere to reporting guidelines and use these at the protocol design stage.

REGISTRATION AND FUNDING

This systematic review is registered on the International prospective register of systematic reviews (PROSPERO) and can be accessed online at the following URL: https://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42020168696This study was funded by the NIHR as part of a Clinical Doctoral Research Fellowship.

Crash Telemetry-Based Injury Severity Prediction is Equivalent to or Out-Performs Field Protocols in Triage of Planar Vehicle Collisions

INTRODUCTION

With the increasing availability of vehicle telemetry technology, there is great potential for Advanced Automatic Collision Notification (AACN) systems to improve trauma outcomes by detecting patients at-risk for severe injury and facilitating early transport to trauma centers.

METHODS

National Automotive Sampling System Crashworthiness Data System (NASS-CDS) data from 1999-2013 were used to construct a logistic regression model (injury severity prediction [ISP] model) predicting the probability that one or more occupants in planar, non-rollover motor vehicle collisions (MVCs) would have Injury Severity Score (ISS) 15+ injuries. Variables included principal direction of force (PDOF), change in velocity (Delta-V), multiple impacts, presence of any older occupant (≥55 years old), presence of any female occupant, presence of right-sided passenger, belt use, and vehicle type. The model was validated using medical records and 2008-2011 crash data from AACN-enabled Michigan (USA) vehicles identified from OnStar (OnStar Corporation; General Motors; Detroit, Michigan USA) records. To compare the ISP to previously established protocols, a literature search was performed to determine the sensitivity and specificity of first responder identification of ISS 15+ for MVC occupants.

RESULTS

The study population included 924 occupants in 836 crash events. The ISP model had a sensitivity of 72.7% (95% Confidence Interval [CI] 41%-91%) and specificity of 93% (95% CI 92%-95%) for identifying ISS 15+ occupants injured in planar MVCs. The current standard 2006 Field Triage Decision Scheme (FTDS) was 56%-66% sensitive and 75%-88% specific in identifying ISS 15+ patients.

CONCLUSIONS

The ISP algorithm comparably is more sensitive and more specific than current field triage in identifying MVC patients at-risk for ISS 15+ injuries. This real-world field study shows telemetry data transmitted before dispatch of emergency medical systems can be helpful to quickly identify patients who require urgent transfer to trauma centers.

How Well Do EMS Providers Predict Intracranial Hemorrhage in Head-Injured Older Adults?

Objective: To evaluate the accuracy of emergency medical services (EMS) provider judgment for traumatic intracranial hemorrhage (tICH) in older patients following head trauma in the field. We also compared EMS provider judgment with other sets of field triage criteria. Methods: This was a prospective observational cohort study conducted with five EMS agencies and 11 hospitals in Northern California. Patients 55 years and older who experienced blunt head trauma were transported by EMS between August 1, 2015 and September 30, 2016, and received an initial cranial computed tomography (CT) imaging, were eligible. EMS providers were asked, "What is your suspicion for the patient having intracranial hemorrhage (bleeding in the brain)?" Responses were recorded as ordinal categories (<1%, 1-5%, >5-10%, >10-50%, or >50%) and the incidences of tICH were recorded for each category. The accuracy of EMS provider judgment was compared to other sets of triage criteria, including current field triage criteria, current field triage criteria plus multivariate logistical regression risk factors, and actual transport. Results: Among the 673 patients enrolled, 319 (47.0%) were male and the median age was 75 years (interquartile range 64-85). Seventy-six (11.3%) patients had tICH on initial cranial CT imaging. The increase in EMS provider judgment correlated with an increase in the incidence of tICH. EMS provider judgment had a sensitivity of 77.6% (95% CI 67.1-85.5%) and a specificity of 41.5% (37.7-45.5%) when using a threshold of 1% or higher suspicion for tICH. Current field triage criteria (Steps 1-3) was poorly sensitive (26.3%, 95% CI 17.7-37.2%) in identifying tICH and current field trial criteria plus multivariate logistical regression risk factors was sensitive (97.4%, 95% CI 90.9-99.3%) but poorly specific (12.9%, 95% CI 10.4-15.8%). Actual transport was comparable to EMS provider judgment (sensitivity 71.1%, 95% CI 60.0-80.0%; specificity 35.3%, 95% CI 31.6-38.3%). Conclusions: As EMS provider judgment for tICH increased, the incidence for tICH also increased. EMS provider judgment, using a threshold of 1% or higher suspicion for tICH, was more accurate than current field triage criteria, with and without additional risk factors included.

[Optimization of criteria for activation of trauma teams : Avoidance of overtriage and undertriage]

INTRODUCTION

Severely injured patients are supposed to be admitted to hospital via the trauma room. Appropriate criteria are contained in the S3 guidelines on the treatment of patients with severe/multiple injuries (S3-GL); however, some of these criteria require scarce hospital resources while the patients then often clinically present as uninjured. There are tendencies to streamline the trauma team activation criteria (TTAC); however, additional undertriage must be avoided. A study group of the emergency, intensive care medicine and treatment of the severely injured section (NIS) is in the process of optimizing the TTAC for the German trauma system.

MATERIAL AND METHODS

In order to solve the objective the following multi-step approach is necessary: a) definition of patients who potentially benefit from TTA, b) verification of the definition in the TraumaRegister DGU® (TR-DGU), c) carrying out a prospective, multicenter study in order to determine overtriage and undertriage, thereby validating the activation criteria and d) revision of the current TTAC.

RESULTS

This article summarizes the consensus criteria of the group assumed to be capable of identifying patients who potentially benefit from TTA. These criteria are used to test if TTA was justified in a specific case; however, as the TTCA of the S3-GL are not fully incorporated into the TR-DGU dataset and because cases must also be considered which were not subject to trauma room treatment and therefore were not included in the TR-DGU, it is necessary to perform a prospective full survey of all individuals in order to be able to measure overtriage and undertriage.

CONCLUSION

Currently, the TR-DGU can only provide limited evidence on the quality of the TTAC recommended in Germany. This problem has been recognized and will be solved by conducting a prospective DGU-supported study, the results of which can be used to improve the TR-DGU dataset in order to enable further considerations on the quality of care (e. g. composition and size of the trauma team).

Simple modification of trauma mechanism alarm criteria published for the TraumaNetwork DGU® may significantly improve overtriage - a cross sectional study

Background

No consensus exists in the literature on the use of uniform emergency room trauma team activation criteria (ERTTAC). Today excessive over- or undertriage rates continue to be a challenge for most trauma centres. Application of ERTTAC, published for use in the German TraumaNetwork DGU^®, at a Swiss trauma centre resulted in a high overtriage rate. The aim of the investigation was to analyse the ERTTAC in detail with the intention of possible improvement.

Methods

The investigation included consecutive adult (age > 15 years) trauma patients treated at the emergency department of a level II trauma centre from 01.01.2013–31.12.2015. All data were collected prospectively. To identify over- and undertriage, patients with an Injury Severity Score (ISS) > 15 were defined as requiring specific emergency room (ER) management. ANOVA, Student’s t-test and chi-square analysis were used for statistical analysis with mean values ± standard deviation.

Results

1378 adult injured (64% male) received ER trauma team treatment (mean age 48.3 ± 21.2 years; ISS 9.7 ± 9.6) during the observation period. Of those, 326 ER patients (23.7%) were diagnosed with an ISS > 15, which proved to be an overtriage of 76.3%. 80/406 trauma patients with an ISS > 15 were not referred to the ER, resulting in an actual undertriage rate of 19.7%, mainly because the criteria list was not observed. Effectively applying ERTTAC according to the protocol in all cases would have reduced undertriage to 2.0% (8/406). The most frequent trigger for trauma team activation was injury mechanism (65%). A simulation revealed that omitting the criterion ‘passenger of car or truck’ (n = 326) would have prevented overtriage in 257 cases, as such lowering overtriage rate to 62.4% and at the same time increasing undertriage by only 8 cases to 7.1%.

Conclusion

Application of ERTTAC as published for TraumaNetwork DGU^® resulted in a lower undertriage but higher overtriage rate than recommended by the American College of Surgeons. Omitting the criterion ‘passenger of car or truck’ markedly improved overtriage with only a minimal increase in undertriage.

Trial registration

NCT02165137; retrospectively registered 11. June 2014.

The Incidence of Traumatic Intracranial Hemorrhage in Head-Injured Older Adults Transported by EMS with and without Anticoagulant or Antiplatelet Use

Field triage guidelines recommend transport of head-injured patients on anticoagulants or antiplatelets to a higher-level trauma center based on studies suggesting a high incidence of traumatic intracranial hemorrhage (tICH). We compared the incidence of tICH in older adults transported by emergency medical services (EMS) with and without anticoagulation or antiplatelet use and evaluated the accuracies of different sets of field triage criteria to identify tICH. This was a prospective, observational study at five EMS agencies and 11 hospitals. Older adults (≥55 years) with head trauma and transported by EMS from August 2015 to September 2016 were eligible. EMS providers completed standardized data forms and patients were followed through emergency department (ED) or hospital discharge. We enrolled 1304 patients; 1147 (88%) received a cranial computed tomography (CT) scan and were eligible for analysis. Four hundred thirty-four (33%) patients had anticoagulant or antiplatelet use and 112 (10%) had tICH. The incidence of tICH in patients with (11%, 95% confidence interval [CI] 8%-14%) and without (9%, 95% CI 7%-11%) anticoagulant or antiplatelet use was similar. Anticoagulant or antiplatelet use was not predictive of tICH on adjusted analysis. Steps 1-3 criteria alone were not sensitive in identifying tICH (27%), whereas the addition of anticoagulant or antiplatelet criterion improved sensitivity (63%). Other derived sets of triage criteria were highly sensitive (>98%) but poorly specific (<11%). The incidence of tICH was similar between patients with and without anticoagulant or antiplatelet use. Use of anticoagulant or antiplatelet medications was not a risk factor for tICH. We were unable to identify a set of triage criteria that was accurate for trauma center need.

Prehospital Assessment of Trauma

The organization of prehospital care for trauma patients began in the military arena. At the urging of multiple stakeholders and providers, these lessons were applied to the civilian setting and emergency medical services were created across the nation. Advances have taken place in the triage, transport, and management of severely injured patients. Many issues remain in the care of trauma patients in the prehospital environment. Collaboration between stakeholders and providers, regionalization of trauma care, and protocol-driven care may be solutions to some of these issues. Further research is necessary to dictate standard of care in this early phase after injury.

Prehospital lactate improves accuracy of prehospital criteria for designating trauma activation level

BACKGROUND

Trauma activation level is determined by prehospital criteria. The American College of Surgeons (ACS) recommends trauma activation criteria; however, their accuracy may be limited. Prehospital lactate has shown promise in predicting trauma center resource requirements. Our objective was to investigate the added value of incorporating prehospital lactate in an algorithm to designate trauma activation level.

METHODS

Air medical trauma patients undergoing prehospital lactate measurement were included. Algorithms using ACS activation criteria (ACS) and ACS activation criteria plus prehospital lactate (ACS+LAC) to designate trauma activation level were compared. Test characteristics and net reclassification improvement (NRI), which evaluates reclassification of patients among risk categories with additional predictive variables, were calculated. Algorithms were compared to predict trauma center need defined as more than 1 unit of blood in the emergency department; spinal cord injury; advanced airway; thoracotomy or pericardiocentesis; ICP monitoring; emergent operative or interventional radiology procedure; or death.

RESULTS

There were 6,347 patients included. Twenty-eight percent had trauma center need. The ACS+LAC algorithm upgraded 256 patients and downgraded 548 patients compared to the ACS algorithm. The ACS+LAC algorithm versus ACS algorithm had an NRI of 0.058 (95% confidence interval [CI], 0.044-0.071; p < 0.01), with an event NRI of -0.5% and nonevent NRI of 6.2%. When weighted to favor changes in undertriage, the ACS+LAC still had a favorable overall reclassification (weighted NRI, 0.041; 95% CI, 0.028-0.054; p = 0.01). The ACS+LAC algorithm increased positive predictive value, negative predictive value, and accuracy. Over-triage was reduced 7.2%, while undertriage only increased 0.7%. The area under the curve was significantly higher for the ACS+LAC algorithm (0.79 vs. 0.76; p < 0.01).

CONCLUSIONS

The ACS+LAC algorithm reclassified patients to more appropriate levels of trauma activation compared to the ACS algorithm. This overall benefit is achieved by significant reduction in overtriage relative to very small increase in undertriage. In the context of trauma team activation, this trade-off may be acceptable, especially in the current health care environment.

LEVEL OF EVIDENCE

Therapeutic/care management study, level III; prognostic/epidemiologic study, level III.

Role of Guideline Adherence in Improving Field Triage

OBJECTIVE

To compare the sensitivity of current field triage practices for identifying high-risk trauma patients to strict guideline adherence, including changes in triage specificity, ambulance transport patterns, and trauma center volumes.

METHODS

This was a pre-planned secondary analysis of an out-of-hospital prospective cohort of injured children and adults transported by 44 EMS agencies to 28 trauma and non-trauma hospitals in 7 Northwest U.S. counties from January 1, 2011 through December 31, 2011. Outcomes included Injury Severity Score (ISS) ≥16 (primary) and early critical resource use. Strict adherence of the triage guidelines was based on evidence in the EMS chart for patients meeting any current field triage criteria, calculated with and without strict interpretation of the age criterion (<15 or >55 years). Due to the probability sampling nature of the cohort, strata and weights were included in all analyses.

RESULTS

17,633 injured patients were transported by EMS (weighted to represent 53,487 transported patients), including 3.1% with ISS ≥16 and 1.7% requiring early critical resources. Field triage sensitivity for identifying patients with ISS ≥16 increased from the current 66.2% (95% CI 60.2-71.7%) to 87.3% (95% CI 81.9-91.2%) for strict adherence without age and to 91.0% (95% CI 86.4-94.2%) for strict adherence with age. Specificity decreased with increasing adherence, from 87.8% (current) to 47.6% (strict adherence without age) and 35.8% (strict adherence with age). Areas under the curve (AUC) were 0.78, 0.73, and 0.72, respectively. Results were similar for patients requiring early critical resources. We estimate the number of triage-positive patients transported each year by EMS to an individual major trauma center (on average) to increase from 1,331 (current) to 5,139 (strict adherence without age) and to 6,256 (strict adherence with age).

CONCLUSIONS

The low sensitivity of current triage practices would be expected to improve with strict adherence to current triage guidelines, with a commensurate decrease in triage specificity and an increase in the number of triage-positive patients transported to major trauma centers.

Undertriage of Trauma-Related Deaths in U.S. Emergency Departments

Introduction

Accurate field triage of critically injured patients to trauma centers is vital for improving survival. We sought to estimate the national degree of undertriage of trauma patients who die in emergency departments (EDs) by evaluating the frequency and characteristics associated with triage to non-trauma centers.

Methods

This was a retrospective cross-sectional analysis of adult ED trauma deaths in the 2010 National Emergency Department Sample (NEDS). The primary outcome was appropriate triage to a trauma center (Level I, II or III) or undertriage to a non-trauma center. We subsequently focused on urban areas given improved access to trauma centers. We evaluated the associations of patient demographics, hospital region and mechanism of injury with triage to a trauma versus non-trauma center using multivariable logistic regression.

Results

We analyzed 3,971 included visits, representing 18,464 adult ED trauma-related deaths nationally. Of all trauma deaths, nearly half (44.5%, 95% CI [43.0–46.0]) of patients were triaged to non-trauma centers. In a subgroup analysis, over a third of urban ED visits (35.6%, 95% CI [34.1–37.1]) and most rural ED visits (86.4%, 95% CI [81.5–90.1]) were triaged to non-trauma centers. In urban EDs, female patients were less likely to be triaged to trauma centers versus non-trauma centers (adjusted odds ratio [OR] 0.83, 95% CI [0.70–0.99]). Highest median household income zip codes (≥$67,000) were less likely to be triaged to trauma centers than lowest median income ($1–40,999) (OR 0.54, 95% CI [0.43–0.69]). Compared to motor vehicle trauma, firearm trauma had similar odds of being triaged to a trauma center (OR 0.90, 95% CI [0.71–1.14]); however, falls were less likely to be triaged to a trauma center (OR 0.50, 95 %CI [0.38–0.66]).

Conclusion

We found that nearly half of all trauma patients nationally and one-third of urban trauma patients, who died in the ED, were triaged to non-trauma centers, and thus undertriaged. Sex and other demographic disparities associated with this triage decision represent targeted opportunities to improve our trauma systems and reduce undertriage.

Cost-Effectiveness of Field Trauma Triage among Injured Adults Served by Emergency Medical Services

BACKGROUND

The American College of Surgeons Committee on Trauma sets national targets for the accuracy of field trauma triage at ≥95% sensitivity and ≥65% specificity, yet the cost-effectiveness of realizing these goals is unknown. We evaluated the cost-effectiveness of current field trauma triage practices compared with triage strategies consistent with the national targets.

STUDY DESIGN

This was a cost-effectiveness analysis using data from 79,937 injured adults transported by 48 emergency medical services agencies to 105 trauma and nontrauma hospitals in 6 regions of the western United States from 2006 through 2008. Incremental differences in survival, quality-adjusted life years (QALYs), costs, and the incremental cost-effectiveness ratio (costs per QALY gained) were estimated for each triage strategy during a 1-year and lifetime horizon using a decision analytic Markov model. We considered an incremental cost-effectiveness ratio threshold of <$100,000 to be cost-effective.

RESULTS

For these 6 regions, a high-sensitivity triage strategy consistent with national trauma policy (sensitivity 98.6%, specificity 17.1%) would cost $1,317,333 per QALY gained, and current triage practices (sensitivity 87.2%, specificity 64.0%) cost $88,000 per QALY gained, compared with a moderate sensitivity strategy (sensitivity 71.2%, specificity 66.5%). Refining emergency medical services transport patterns by triage status improved cost-effectiveness. At the trauma-system level, a high-sensitivity triage strategy would save 3.7 additional lives per year at a 1-year cost of $8.78 million, and a moderate sensitivity approach would cost 5.2 additional lives and save $781,616 each year.

CONCLUSIONS

A high-sensitivity approach to field triage consistent with national trauma policy is not cost-effective. The most cost-effective approach to field triage appears closely tied to triage specificity and adherence to triage-based emergency medical services transport practices.

Improving early identification of the high-risk elderly trauma patient by emergency medical services

STUDY OBJECTIVE

We sought to (1) define the high-risk elderly trauma patient based on prognostic differences associated with different injury patterns and (2) derive alternative field trauma triage guidelines that mesh with national field triage guidelines to improve identification of high-risk elderly patients.

METHODS

This was a retrospective cohort study of injured adults ≥65 years transported by 94 EMS agencies to 122 hospitals in 7 regions from 1/1/2006 through 12/31/2008. We tracked current field triage practices by EMS, patient demographics, out-of-hospital physiology, procedures and mechanism of injury. Outcomes included Injury Severity Score≥16 and specific anatomic patterns of serious injury using abbreviated injury scale score ≥3 and surgical interventions. In-hospital mortality was used as a measure of prognosis for different injury patterns.

RESULTS

33,298 injured elderly patients were transported by EMS, including 4.5% with ISS≥16, 4.8% with serious brain injury, 3.4% with serious chest injury, 1.6% with serious abdominal-pelvic injury and 29.2% with serious extremity injury. In-hospital mortality ranged from 18.7% (95% CI 16.7-20.7) for ISS≥16 to 2.9% (95% CI 2.6-3.3) for serious extremity injury. The alternative triage guidelines (any positive criterion from the current guidelines, GCS≤14 or abnormal vital signs) outperformed current field triage practices for identifying patients with ISS≥16: sensitivity (92.1% [95% CI 89.6-94.1%] vs. 75.9% [95% CI 72.3-79.2%]), specificity (41.5% [95% CI 40.6-42.4%] vs. 77.8% [95% CI 77.1-78.5%]). Sensitivity decreased for individual injury patterns, but was higher than current triage practices.

CONCLUSIONS

High-risk elderly trauma patients can be defined by ISS≥16 or specific non-extremity injury patterns. The field triage guidelines could be improved to better identify high-risk elderly trauma patients by EMS, with a reduction in triage specificity.

Systolic blood pressure criteria in the National Trauma Triage Protocol for geriatric trauma: 110 is the new 90

BACKGROUND

Undertriage is a concern in geriatric patients. The National Trauma Triage Protocol (NTTP) recognized that systolic blood pressure (SBP) less than 110 mm Hg may represent shock in those older than 65 years. The objective was to evaluate the impact of substituting an SBP of less than 110 mm Hg for the current SBP of less than 90 mm Hg criterion within the NTTP on triage performance and mortality.

METHODS

Subjects undergoing scene transport in the National Trauma Data Bank (2010-2012) were included. The outcome of trauma center need was defined as Injury Severity Score (ISS) greater than 15, intensive care unit admission, urgent operation, or emergency department death. Geriatric (age > 65 years) and adult (age, 16-65 years) cohorts were compared. Triage characteristics and area under the curve (AUC) were compared between SBP of less than 110 mm Hg and SBP of less than 90 mm Hg. Hierarchical logistic regression was used to determine whether geriatric patients newly triaged positive under this change (SBP, 90-109 mm Hg) have a risk of mortality similar to those triaged positive with SBP of less than 90 mm Hg.

RESULTS

There were 1,555,944 subjects included. SBP of less than 110 mm Hg had higher sensitivity but lower specificity in geriatric (13% vs. 5%, 93% vs. 99%) and adult (23% vs. 10%, 90% vs. 98%) cohorts. AUC was higher for SBP of less than 110 mm Hg individually in both geriatric and adult (p < 0.01) cohorts. Within the NTTP, the AUC was similar for SBP of less than 110 mm Hg and SBP of less than 90 mm Hg in geriatric subjects but was higher for SBP of less than 90 mm Hg in adult subjects (p < 0.01). Substituting SBP of less than 110 mm Hg resulted in an undertriage reduction of 4.4% with overtriage increase of 4.3% in the geriatric cohort. Geriatric subjects with SBP of 90 mm Hg to 109 mm Hg had an odds of mortality similar to those of geriatric patients with SBP of less than 90 mm Hg (adjusted odds ratio, 1.03; 95% confidence interval, 0.88-1.20; p = 0.71).

CONCLUSION

SBP of less than 110 mm Hg increases sensitivity. SBP of less than 110 mm Hg has discrimination as good as that of SBP of less than 90 mm Hg, with superior improvements in undertriage relative to overtriage in geriatric patients. Geriatric patients newly triaged to be positive under this change have a risk of mortality similar to those under the current SBP criterion. This change in SBP criteria may be merited in geriatric patients, warranting further study to consider elevation to a Step 1 criterion in the NTTP.

LEVEL OF EVIDENCE

Diagnostic study, level IV.

Physiologic field triage criteria for identifying seriously injured older adults

OBJECTIVE

To evaluate the ability of out-of-hospital physiologic measures to predict serious injury for field triage purposes among older adults and potentially reduce the undertriage of seriously injured elders to non-trauma hospitals.

METHODS

This was a retrospective cohort study involving injured adults 55 years and older transported by 94 emergency medical services (EMS) agencies to 122 hospitals (trauma and non-trauma) in 7 regions of the western United States from January 1, 2006 to December 31, 2008. We evaluated initial out-of-hospital Glasgow Coma Scale (GCS) score, systolic blood pressure (SBP), respiratory rate, heart rate, shock index (SBP ÷ heart rate), out-of-hospital procedures, mechanism of injury, and patient demographics. The primary outcome was "serious injury," defined as Injury Severity Score (ISS) ≥ 16, as a measure of trauma center need. We used multivariable regression models, fractional polynomials and binary recursive partitioning to evaluate appropriate physiologic cut-points and the value of different physiologic triage criteria.

RESULTS

A total of 44,890 injured older adults were evaluated and transported by EMS, of whom 2,328 (5.2%) had ISS ≥ 16. Nonlinear associations existed between all physiologic measures and ISS ≥ 16 (unadjusted and adjusted p ≤ 0.001 for all,), except for heart rate (adjusted p = 0.48). Revised physiologic triage criteria included GCS score ≤ 14; respiratory rate < 10 or > 24 breaths per minute or assisted ventilation; and SBP < 110 or > 200 mmHg. Compared to current triage practices, the revised criteria would increase triage sensitivity from 78.6 to 86.3% (difference 7.7%, 95% CI 6.1-9.6%), reduce specificity from 75.5 to 60.7% (difference 14.8%, 95% CI 14.3-15.3%), and increase the proportion of patients without serious injuries transported to major trauma centers by 60%.

CONCLUSIONS

Existing out-of-hospital physiologic triage criteria could be revised to better identify seriously injured older adults at the expense of increasing overtriage to major trauma centers.

The cost of overtriage: more than one-third of low-risk injured patients were taken to major trauma centers

Regionalized trauma care has been widely implemented in the United States, with field triage by emergency medical services (EMS) playing an important role in identifying seriously injured patients for transport to major trauma centers. In this study we estimated hospital-level differences in the adjusted cost of acute care for injured patients transported by 94 EMS agencies to 122 hospitals in 7 regions, overall and by injury severity. Among 301,214 patients, the average adjusted per episode cost of care was $5,590 higher in a level 1 trauma center than in a nontrauma hospital. We found hospital-level differences in cost among patients with minor, moderate, and serious injuries. Of the 248,342 low-risk patients-those who did not meet field triage guidelines for transport to trauma centers-85,155 (34.3 percent) were still transported to major trauma centers, accounting for up to 40 percent of acute injury costs. Adhering to field triage guidelines that minimize the overtriage of low-risk injured patients to major trauma centers could save up to $136.7 million annually in the seven regions we studied.

Undertriage of major trauma patients in the US emergency departments

BACKGROUND

There is evidence that regionalized trauma care and appropriate triage of major trauma patients improve patient outcomes. However, the national rate of undertriage and diagnoses of undertriaged patients are unknown.

METHODS

We used the 2010 Nationwide Emergency Department Sample to estimate the national rate of undertriage, identify the prevalent diagnoses, and conduct a simulation analysis of the capacity increase required for level I and II trauma centers (TCs) to accommodate undertriaged patients. Undertriaged patients were those with major trauma, injury severity score ≥ 16, who received definitive care at nontrauma centers (NTCs), or level III TCs. The rate of undertriage was calculated with those receiving definitive care at an NTC center or level III center as a fraction of all major trauma patients.

RESULTS

The estimated number of major trauma patient discharges in 2010 was 232448. Level of care was known for 197702 major trauma discharges, and 34.0% were undertriaged in emergency departments (EDs). Elderly patients were at a significantly higher risk of being undertriaged. Traumatic brain injury (TBI) was the most common diagnosis, 40.2% of the undertriaged patient diagnoses. To accommodate all undertriaged patients, level I and II TCs nationally would have to increase their capacity by 51.5%.

CONCLUSIONS

We found that more than one-third of US ED major trauma patients were undertriaged, and more than 40% of undertriaged diagnoses were TBIs. A significant capacity increase at level I and II TCs to accommodate these patients appears not feasible.