Emergency Department Time Course for Mild Traumatic Brain Injury Workup

Improving the Management of Adults With Mild Traumatic Brain Injury: An Initiative to Reduce Unnecessary Computed Tomographic Scans in the Emergency Department

The overuse of computed tomographic (CT) scans for patients who present to the emergency department (ED) after mild traumatic brain injury (mTBI) has been well-documented. The Canadian Computed Tomography Head Rule (CCHR) is a validated tool to guide ED providers in determining the need for emergent CT of mTBI patients. The purpose of this project was to reduce radiation exposure and ED length of stay by using the CCHR to decrease unnecessary CT scans in adults with TBI. Cost of care was also estimated. The CCHR implementation strategy included an education program for ED staff. The use of the CCHR was promoted throughout the intervention period. The outcomes measured were the number of CT scans ordered, ED length of stay, and the cost of avoidable CT scans. Data were collected through medical record reviews completed by the project leader and were evaluated using the independent samples t test. A total of 600 medical records were reviewed. There was a significant difference between adherence to the CCHR before (M = 64.6%) and after provider education (M = 74.3%). The percentage of CT scans that could have been avoided significantly decreased from baseline (M = 0.63) after provider education (M = 0.46). Length of stay for mTBI patients who were managed based on the CCHR (M = 184.9) was significantly less than the length of stay for those who were not (M = 260.1). The cost of avoidable scans was decreased by 37% over the course of the project. There were no incidents of missed diagnosis found. By increasing awareness of the CCHR and promoting its use, the number of head CT scans ordered, cost of care, and ED length of stay for patients who present after mTBI were significantly improved.

Diagnostic performance of S100B as a rule-out test for intracranial pathology in head-injured patients presenting to the emergency department who meet NICE Head Injury Guideline criteria for CT-head scan

BACKGROUND

Traumatic brain injury is a common ED presentation. CT-head utilisation is escalating, exacerbating resource pressure in the ED. The biomarker S100B could assist clinicians with CT-head decisions by excluding intracranial pathology. Diagnostic performance of S100B was assessed in patients meeting National Institute of Health and Clinical Excellence Head Injury Guideline (NICE HIG) criteria for CT-head within 6 and 24 hours of injury.

METHODS

This multicentre prospective observational study included adult patients presenting to the ED with head injuries between May 2020 and June 2021. Informed consent was obtained from patients meeting NICE HIG CT-head criteria. A venous blood sample was collected and serum was tested for S100B using a Cobas Elecsys-S100 module; >0.1 µg/mL was the threshold used to indicate a positive test. Intracranial pathology reported on CT-head scan by the duty radiologist was used as the reference standard to review diagnostic performance.

RESULTS

This study included 265 patients of whom 35 (13.2%) had positive CT-head findings. Within 6 hours of injury, sensitivity of S100B was 93.8% (95% CI 69.8% to 99.8%) and specificity was 30.8% (22.6% to 40.0%). Negative predictive value (NPV) was 97.3% (95% CI 84.2% to 99.6%) and area under the curve (AUC) was 0.73 (95% CI 0.61 to 0.85; p=0.003). Within 24 hours of injury, sensitivity was 82.9% (95% CI 66.4% to 93.44%) and specificity was 43.0% (95% CI 36.6% to 49.7%). NPV was 94.29% (95% CI 88.7% to 97.2%) and AUC was 0.65 (95% CI 0.56 to 0.74; p=0.046). Theoretically, use of S100B as a rule-out test would have reduced CT-head scans by 27.1% (95% CI 18.9% to 36.8%) within 6 hours and 37.4% (95% CI 32.0% to 47.2%) within 24 hours. The risk of missing a significant injury with this approach would have been 0.75% (95% CI 0.0% to 2.2%) within 6 hours and 2.3% (95% CI 0.5% to 4.1%) within 24 hours.

CONCLUSION

Within 6 hours of injury, S100B performed well as a diagnostic test to exclude significant intracranial pathology in low-risk patients presenting with head injury. In theory, if used in addition to NICE HIGs, CT-head rates could reduce by one-quarter with a potential miss rate of <1%.

Development of an electrochemical impedance spectroscopy based biosensor for detection of ubiquitin C-Terminal hydrolase L1

Year over year, the incidence of traumatic brain injury (TBI) in the population is dramatically increasing; thus, timely diagnosis is crucial for improving patient outcomes in the clinic. Ubiquitin C-terminal hydrolase L1 (UCH-L1), a blood-based biomarker, has been approved by the FDA as a promising quantitative indicator of mild TBI that arises in blood serum shortly after injury. Current gold standard techniques for its quantitation are time-consuming and require specific laboratory equipment. Hence, development of a hand-held device is an attractive alternative. In this study, we report a novel system for rapid, one-step electrochemical UCH-L1 detection. Electrodes were functionalized with anti-UCH-L1 antibody, which was used as a molecular recognition element for selective sensing of UCH-L1. Electrochemical impedance spectroscopy (EIS) was used as a transduction method to quantify its binding. When the electrode was incubated with different concentrations of UCH-L1, impedance signal increased against a concentration gradient with high logarithmic correlation. Upon single-frequency analysis, a second calibration curve with greater signal to noise was obtained, which was used to distinguish physiologically relevant concentrations of UCH-L1. Notably, our system could detect UCH-L1 within 5 min, without a washing step nor bound/free separation, and had resolution across concentrations ranging from 1 pM to 1000 pM within an artificial serum sample. These attributes, together with the miniaturization potential afforded by an impedimetric sensing platform, make this platform an attractive candidate for scale-up as a device for rapid, on-site detection of TBI. These findings may aid in the future development of sensing systems for quantitative TBI detection.

Can serum biomarkers be used to rule out significant intracranial pathology in emergency department patients with mild traumatic brain injury? A Systemic Review & Meta-Analysis

BACKGROUND

Interest has mounted into the use of objective clinical biomarkers for traumatic brain injury (TBI). This systematic review and meta-analysis aimed to synthesise the existing evidence investigating the use of serum & plasma biomarkers to exclude significant intracranial injuries seen on CT head scans in patients that present to ED with TBI.

METHODS

The primary outcome was to review the diagnostic accuracy (sensitivity & specificity) of S100B, GFAP and UCH-L1 to exclude significant intracranial pathology on CT head scan in adults presenting with TBI. Secondary outcomes investigated biomarker performance at different time points, in isolated TBI and multi-trauma and with pre-specified cut offs. Systematic searches were conducted on MEDLINE ® (via PubMed), Cochrane electronic databases and EMBASE from 1^st January 2000 until June 2020. Bias was assessed using QUADAS 2 tool. A narrative synthesis and meta-analysis were performed. PROSPERO registration number CRD42020212206.

RESULTS

After screening, 22 papers were included. The total number of patients with TBI was 9,416. There was significant variation regarding study design, population selection and the clinical threshold/decision rule for CT head request. The diagnostic accuracy of S100B as measured by the range of individual sensitivities and specificities were 63-100% and 5-58%, respectively. Individual sensitivities and specificities for GFAP were 67-100% and 0-89% and for UCH-L1 were 61-100% and 21-63.7% respectively. When measured within 3 hours individual sensitivities & specificities for S100B were 98-100% & 20-58% respectively. The quality of evidence for the primary outcome overall was low. The quality of evidence was low for all secondary outcomes apart from studies that used a pre-specified cut off for S100B which had a moderate strength of evidence.

CONCLUSION

The overall quality of evidence regarding the diagnostic accuracy of single biomarkers as a rule out for significant intracranial injury seen on CT head scans in ED patients with TBI is low. Based on current evidence, S100B is the only single biomarker with a validated clinical platform, pre-determined cut off threshold and moderate quality evidence; at this stage making it the biomarker of choice. More robust clinical outcome and economic impact data is required to support its incorporation into clinical decision tools.

Accuracy of a rapid glial fibrillary acidic protein/ubiquitin carboxyl-terminal hydrolase L1 test for the prediction of intracranial injuries on head computed tomography after mild traumatic brain injury

OBJECTIVE

The objective was to determine the accuracy of a new, rapid blood test combining measurements of both glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) for predicting acute traumatic intracranial injury (TII) on head CT scan after mild traumatic brain injury (mTBI).

METHODS

Analysis of banked venous plasma samples from subjects completing the Prospective Clinical Evaluation of Biomarkers of Traumatic Brain Injury (ALERT-TBI) trial, enrolled 2012-2014 at 22 investigational sites in the United States and Europe. All subjects were ≥18 years old, presented to an emergency department (ED) with a nonpenetrating head injury and Glasgow Coma Scale score (GCS) 9-15 (mild to moderate TBI), underwent head CT scanning as part of their clinical care, and had blood sampling within 12 h of injury. Plasma concentrations of GFAP and UCH-L1 were measured using i-STAT Alinity and TBI plasma cartridge and compared to acute TII on head CT scan.

RESULTS

Of the 2011 subjects enrolled in ALERT-TBI, 1918 had valid CT scans and plasma specimens for testing and 1901 (99.1%) had GCS 13-15 (mTBI), for which the rapid test was intended. Among these subjects, the rapid test had a sensitivity of 0.958 (95% confidence interval [CI] = 0.906 to 0.982), specificity of 0.404 (95% CI = 0.382 to 0.427), negative predictive value of 0.993 (95% CI = 0.985 to 0.997), and positive predictive value of 0.098 (95% CI = 0.082 to 0.116) for acute TII.

CONCLUSIONS

A rapid i-STAT-based test had high sensitivity for prediction of acute TII, comparable to lab-based platforms. The speed, portability, and high accuracy of this test may facilitate clinical adoption of brain biomarker testing as an aid to head CT decision making in EDs.

Challenges in the acute identification of mild traumatic brain injuries: results from an emergency department surveillance study

OBJECTIVES

To establish the proportion of mild traumatic brain injury (mTBI) diagnosis among people presenting to an emergency department (ED), to determine the accuracy of recorded ED diagnoses. We also aimed to describe challenges in mTBI case identification and its acute hospital management.

DESIGN AND SETTING

A retrospective chart review of all ED attendances to a major trauma hospital, over a 9-month period (June 2015-February 2016).

PARTICIPANTS

Adults aged 18-65 years consecutively presenting to an ED.

PRIMARY OUTCOME MEASURES

Proportion of mTBI diagnosis among ED attendances (ie, confirmed mTBI based on the WHO criteria or indeterminate mTBI based on secondary criteria), and proportion of accurately recorded mTBI diagnosis by ED clinicians (ie, 'mTBI', 'concussion').

RESULTS

Of 30 479 ED attendances, 351 (1.15%) confirmed mTBI diagnosis and 180 (0.6%) indeterminate diagnosis were identified. Only 81 (23.1%) individuals with a confirmed mTBI had a 'mTBI diagnosis' clearly recorded in the medical notes. Of the allocated discharge diagnosis codes to the two identified cohorts, 89.8% were not indicative of mTBI. Intracranial injuries were found in 31 (8.5%) confirmed cases. Glasgow Coma Scale scores were consistently assessed in the ED but identified only 117 (33.3%) confirmed mTBI cases. Post-traumatic amnesia (PTA) testing was able to confirm acute cognitive impairment in 113 (62.1%) of those who were tested (182, 51.3%).

CONCLUSIONS

mTBI is a common, but an under-recognised cause for ED attendance. Despite challenges, the use of an operational definition such as the WHO diagnostic criteria can improve accuracy in mTBI identification. Acute management may be enhanced by rapid assessment of PTA.