Injury Severity Score Inflation Resulting From Pan–Computed Tomography in Patients With Blunt Trauma

Association between major trauma centre care and outcomes of adult patients injured by low falls in England and Wales

BACKGROUND

Disability and death due to low falls is increasing worldwide and disproportionately affects older adults. Current trauma systems were not designed to suit the needs of these patients. This study assessed the association between major trauma centre (MTC) care and outcomes in adult patients injured by low falls.

METHODS

Data were obtained from the Trauma Audit and Research Network on adult patients injured by falls from <2 m between 2017 and 2019 in England and Wales. 30-day survival, length of hospital stay and discharge destination were compared between MTCs and trauma units or local emergency hospitals (TU/LEHs) using an adjusted multiple logistic regression model.

RESULTS

127 334 patients were included, of whom 27.6% attended an MTC. The median age was 79.4 years (IQR 64.5-87.2 years), and 74.2% of patients were aged >65 years. MTC care was not associated with improved 30-day survival (adjusted OR (AOR) 0.91, 95% CI 0.87 to 0.96, p<0.001). Transferred patients had a significant impact on the results. After excluding transferred patients, MTC care was associated with greater odds of 30-day survival (AOR 1.056, 95% CI 1.001 to 1.113, p=0.044). MTC care was also associated with greater odds of 30-day survival in the most severely injured patients (AOR 1.126, 95% CI 1.04 to 1.22, p=0.002), but not in patients aged >65 years (AOR 1.038, 95% CI 0.982 to 1.097, p=0.184).

CONCLUSION

MTC care was not associated with improved survival compared with TU/LEH care in the whole cohort. Patients who were transferred had a significant impact on the results. In patients who are not transferred, MTC care is associated with greater odds of 30-day survival in the whole cohort and in the most severely injured patients. Future research must determine the optimum means of identifying patients in need of higher-level care, the components of care which improve patient outcomes, develop patient-focused outcomes which reflect the characteristics and priorities of contemporary trauma patients, and investigate the need for transfer in specific subgroups of patients.

Non-Selective Thoracic Computed Tomography in Trauma Patients Results in Injury Severity Score Inflation

INTRODUCTION

Extensive research relying on Injury Severity Scores (ISS) reports a mortality benefit from routine non-selective thoracic CTs (an integral part of pan-computed tomography (pan-CT)s). Recent research suggests this mortality benefit may be artifact. We hypothesized that the use of pan-CTs inflates ISS categorization in patients, artificially affecting admission rates and apparent mortality benefit.

METHODS

Eight hundred and eleven patients were identified with an ISS >15 with significant findings in the chest area. Patient charts were reviewed and scores were adjusted to exclude only occult injuries that did not affect treatment plan. Pearson chi-square tests and multivariable logistic regression were used to compare adjusted cases vs non-adjusted cases.

RESULTS

After adjusting for inflation, 388 (47.8%) patients remained in the same ISS category, 378 (46.6%) were reclassified into 1 lower ISS category, and 45 (5.6%) patients were reclassified into 2 lower ISS categories. Patients reclassified by 1 category had a lower rate of mortality (P < 0.001), lower median total hospital LOS (P < .001), ICU days (P < .001), and ventilator days (P = 0.008), compared to those that remained in the same ISS category.

CONCLUSION

Injury Severity Score inflation artificially increases survival rate, perpetuating the increased use of pan-CTs. This artifact has been propagated by outdated mortality prediction calculation methods. Thus, prospective evaluations of algorithms for more selective CT scanning are warranted.

Trauma Early Mortality Prediction Tool (TEMPT) for assessing 28-day mortality

Background

Prior mortality prediction models have incorporated severity of anatomic injury quantified by Abbreviated Injury Severity Score (AIS). Using a prospective cohort, a new score independent of AIS was developed using clinical and laboratory markers present on emergency department presentation to predict 28-day mortality.

Methods

All patients (n=1427) enrolled in an ongoing prospective cohort study were included. Demographic, laboratory, and clinical data were recorded on admission. True random number generator technique divided the cohort into derivation (n=707) and validation groups (n=720). Using Youden indices, threshold values were selected for each potential predictor in the derivation cohort. Logistic regression was used to identify independent predictors. Significant variables were equally weighted to create a new mortality prediction score, the Trauma Early Mortality Prediction Tool (TEMPT) score. Area under the curve (AUC) was tested in the validation group. Pairwise comparison of Trauma Injury Severity Score (TRISS), Revised Trauma Score, Glasgow Coma Scale, and Injury Severity Score were tested against the TEMPT score.

Results

There was no difference between baseline characteristics between derivation and validation groups. In multiple logistic regression, a model with presence of traumatic brain injury, increased age, elevated systolic blood pressure, decreased base excess, prolonged partial thromboplastin time, increased international normalized ratio (INR), and decreased temperature accurately predicted mortality at 28 days (AUC 0.93, 95% CI 0.90 to 0.96, P<0.001). In the validation cohort, this score, termed TEMPT, predicted 28-day mortality with an AUC 0.94 (95% CI 0.92 to 0.97). The TEMPT score preformed similarly to the revised TRISS score for severely injured patients and was highly predictive in those having mild to moderate injury.

Discussion

TEMPT is a simple AIS-independent mortality prediction tool applicable very early following injury. TEMPT provides an AIS-independent score that could be used for early identification of those at risk of doing poorly following even minor injury.

Level of evidence

Level II.

The modified rapid emergency medicine score: A novel trauma triage tool to predict in-hospital mortality

BACKGROUND

Trauma systems currently rely on imperfect and subjective tools to prioritize responses and resources, thus there is a critical need to develop a more accurate trauma severity score. Our objective was to modify the Rapid Emergency Medicine (REMS) Score for the trauma population and test its accuracy as a predictor of in-hospital mortality when compared to other currently used scores, including the Revised Trauma Score (RTS), the Injury Severity Score (ISS), the "Mechanism, Glasgow Coma Scale, Age and Arterial Pressure" (MGAP) score, and the Shock Index (SI) score.

METHODS

The two-part study design involved both a modification step and a validation step. The first step incorporated a retrospective analysis of a local trauma database (3680 patients) where three components of REMS were modified to more accurately represent the trauma population. Using clinical judgment and goodness-of-fit tests, systolic blood pressure was substituted for mean arterial pressure, the weighting of age was reduced, and the weighting of Glasgow Coma Scale was increased. The second part comprised validating the new modified REMS (mREMS) score retrospectively on a U.S. National Trauma Databank (NTDB) that included 429,711 patients admitted with trauma in 2012. The discriminate power of mREMS was compared to other trauma scores using the area under the receiver operating characteristic (AUC) curve.

RESULTS

Overall the mREMS score with an AUC of 0.967 (95% CI: 0.963-0.971) was demonstrated to be higher than RTS (AUC 0.959 [95% CI: 0.955-0.964]), ISS (AUC 0.780 [95% CI 0.770-0.791]), MGAP (AUC 0.964 [95% CI: 0.959-0.968]), and SI (AUC 0.670 [95% CI: 0.650-0.690]) in predicting in-hospital mortality on the NTDB.

CONCLUSION

In the trauma population, mREMS is an accurate predictor of in-hospital mortality, outperforming other used scores. Simple and objective, mREMS may hold value in the pre-hospital and emergency department setting in order to guide trauma team responses.

Whole body CT versus selective radiological imaging strategy in trauma: an evidence-based clinical review

BACKGROUND

Trauma patients often present with injuries requiring resuscitation and further evaluation. Many providers advocate for whole body computed tomography (WBCT) for rapid and comprehensive diagnosis of life-threatening injuries.

OBJECTIVE

Evaluate the literature concerning mortality effect, emergency department (ED) length of stay, radiation, and incidental findings associated with WBCT.

DISCUSSION

Physicians have historically relied upon history and physical examination to diagnose life-threatening injuries in trauma. Diagnostic imaging modalities including radiographs, ultrasound, and computed tomography have demonstrated utility in injury detection. Many centers routinely utilize WBCT based on the premise this test will improve mortality. However, WBCT may increase radiation and incidental findings when used without considering pre-test probability of actionable traumatic injuries. Studies supporting WBCT are predominantly retrospective and incorporate trauma scoring systems, which have significant design weaknesses. The recent REACT-2 trial randomized trauma patients with high index of suspicion for actionable injuries to WBCT versus selective imaging and found no mortality difference. Additional prospective trials evaluating WBCT in specific trauma subgroups (e.g. polytrauma) are needed to evaluate benefit. In the interim, the available data suggests clinicians should adopt a selective imaging strategy driven by history and physical examination.

CONCLUSIONS

While observational data suggests an association between WBCT and a benefit in mortality and ED length of stay, randomized controlled data suggests no mortality benefit to this diagnostic tool. The literature would benefit from confirmatory studies of the use of WBCT in trauma sub-groups to clarify its impact on mortality for patients with specific injury patterns.