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NEWS: Safety and resource utilization for TBI patients based on the Modified Brain Injury Guidelines (mBIG): A multicenter prospective-retrospective validation study

By Currents Editor posted 08-08-2022 09:50


Arshdeep Kaur, MD
PGY-3 resident in Neurology
Wayne State University/Detroit Medical Center 

Wazim Mohamed, MD
Associate Professor of Neurology and Neurosurgery
Wayne State University

Khan, Abid D., et al. "A multicenter validation of the Modified Brain Injury Guidelines (mBIG): are they safe and effective?." The Journal of Trauma and Acute Care Surgery (2022).


Traumatic brain injury accounts for a substantial number of ER visits and hospital admissions requiring extensive resource utilization. This patient population requires strategic triaging, testing, and resource allocation. The Brain injury guidelines (BIG) help stratify mild TBI with intracranial hemorrhages (ICH) not requiring repeat imaging, hospital admission or a neurosurgery consult but never addressed the differences in resource allocation.

This study aimed to study the safety of a refined treatment algorithm, modified Brain injury guidelines (mBIG), to assess improvements in resource utilization. This was a retrospective observational study with prospective data collected from TBI patients from three Level 1 trauma centers. Based on these guidelines, patients with TBI and ICH were classified into 3 groups. mBIG 1 were observed for 6 hours. If there was no decline in the neurological exam, they were discharged with no neurosurgery consult or repeat imaging. mBIG 2 were admitted for a 24-hour observation period. If there was no decline in the neurological exam, these patients were discharged with no repeat imaging or neurosurgery consult. mBIG 3 included more gravely injured and critical patients requiring admission, repeat imaging, and neurosurgery consultation.

mBIG 1 and 2 were compared to a previously published evaluation of the BIG cohort. mBIG 3 were excluded as their management was unchanged from standard TBI care at these institutions prior to incorporation of mBIG. Other exclusions included intubation within the observation period, previous skull trauma, transfers with no initial imaging available, and presentation 48-hours after the injury.


764 patients were included of which 496 were from August 2017 to February 2021 post mBIG implementation (test group) and 268 from original BIG analysis (comparison group). The mean age for the study group was 53.7 years and 44.0% were female. No significant differences were seen in ISS or admission GCS between the two groups. Complications including rates of subdural hematoma, ICH, subarachnoid hemorrhage, skull fracture, midline shift, and the rates of clinical or radiographic progression, neurosurgery intervention and mortality was similar between the two groups

More patients qualified as mBIG 1 vs BIG 1 after updated guideline implementation (45.0% vs 36.9%, p=0.032). Incidence of EDHs were lower with mBIG (0% vs 2.6%, p<0.01). Number of CT scans (2 [1,2] vs 2 [2,3], p<0.0001) and neurosurgery consults (61.9% vs 95.9%, p<0.01) decreased significantly in the post mBIG implementation period. Shorter length of stay (LOS) was seen for both, hospital (2 [1,4] vs 2 [2,4], p=0.013) and ICU (0 [0,1] vs 1 [1,2], p<0.01) in the test group. The readmission rate was also found to be lower (3.2%) with mBIG as compared to 6.5-8.6% in standard trauma patients.

Eight patients (1.6%) including 2 mBIG 1 and 6 mBIG 2 declined in their neurological exam during the observation period after mBIG implementation. One mBIG 2 patient required craniotomy after clinical and radiographic decline but was ultimately discharged from the hospital with a GCS of 15. Another mBIG 2 patient went for comfort measures and subsequently died after clinical and radiological worsening due to a pre-existing diagnosis of metastatic cancer. The remaining six patients had isolated clinical progression with no radiological progression, likely secondary to non-traumatic causes and were discharged with a GCS 15 without needing any NSGY intervention.


TBI poses a substantial burden on the health care resources with increased allocation with older age. The standard trauma model mandates repeat brain imaging, neurosurgery consultations, and hospital admissions. The authors conclude that the modified Brain Injury Guidelines (mBIG) are safe and effective to implement in trauma patients. The low readmission rates and unchanged mortality elucidates the safety of this algorithm. These guidelines improved resource utilization evident from fewer imaging, reduced neurosurgery consults, and decreased LOS in the hospital and ICU.

The mBIG guidelines are a refined version of the original Brain Injury Guidelines (BIG) published in 2014 with improved patient safety. This study has many strengths. The safety profile is better with characterization of EDHs as mBIG 3. mBIG relies on patient’s return to baseline GCS and not merely on the absence of decline in neurological exam as done in original BIG which ensures safe discharges. In patients where neurological exam cannot be reliably assessed, mBIG 1 and 2 are upgraded to mBIG 3. There is better SAH radiographic classification in mBIG depending on the extent of sulcal involvement and thickness which leaves less room for variable subjective interpretation. mBIG also allows inclusion of patients with concomitant non-neurological injuries which was not done in the original study. Defining criteria and inclusion of alcohol intoxication in the guidelines help differentiate patients with non-traumatic causes of decreased mentation. The study also acknowledged any increased risk in ICH patients taking DOACs and classified them as mBIG 3. Recent studies showing no increased risk of ICH progression with aspirin, validated the mBIG criteria to not categorize them as mBIG 3. This contributed to higher proportion of mBIG 1 patient as compared to BIG 1.

However, it was not possible to perform multivariable analysis with adjustment for confounders due to low event rate. Some institutional differences in practice patterns may also be a confounding factor. Only 2 of the 3 institutions participating in the original study (comparison group) were included in this trial. The ramifications of the patient populations and practice pattern differences between the third institution from either group must be recognized. In addition, the compliance with all aspects of these new guidelines was variable over time and across the institutions.

Future directions include utilization and review of mBIG at smaller referring centers where the algorithm can conserve significant resources. A true assessment of cost effectiveness should also be done to understand the financial healthcare benefits gained by implementation of mBIG. 


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