This Is BIG – New AAST Brain Injury Guidelines

August 24, 2023

Written by Laura Murphy

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This article was a multi-institutional prospective validation of the American Association for Surgery of Trauma (AAST) Brain Injury Guidelines (BIG), which were developed to guide effective resource utilization for traumatic brain injury. The validation study demonstrated that this system was accurate and safe and that its implementation can reduce CT scan utilization and neurosurgical consultation.

What’s the BIG deal?
Traumatic brain injury is associated with high morbidity and mortality, and its management requires significant resource utilization in the emergency department. BIG puts patients into three groups based on medical history, neurologic exam (focal deficits, pupillary exam, Glasgow Coma Scale (GCS) score on admission), and initial head CT findings. Recommendations were proposed regarding need for hospitalization, repeat imaging, and neurosurgical consultations based on BIG category (see Figure below).

The validation study was a prospective, observational study including ~2000 patients enrolled at 10 Level I and II trauma centers, with primary outcome of requirement of neurosurgical intervention.  Secondary measures included clinical deterioration, progression on repeat head CT (RHCT), post-discharge ED visits, and 30-day readmissions. Notably, this study did not focus on functional neurologic outcomes or long-term follow up data.

All of the patients that required neurosurgical intervention were BIG-3. Of BIG-1 and BIG-2 patients, a few (1.3% BIG-1 and 7.1% BIG-2) had progression on repeat imaging, and even fewer (0% BIG-1 and 0.7% BIG-2) had clinical deterioration. However, none of these patients ultimately required neurosurgical intervention, and, there were no TBI-related post-discharge emergency department visits or 30-day readmissions.

While agreement between assigned and final BIG categories was excellent, implementation of BIG protocol with regard to routine RHCT and neurosurgical consultation was generally poor (only five centers had greater than 30% compliance), meaning that many BIG 1 and BIG 2 patients received RHCT and neurosurgical consultations anyway. The authors concluded that implementing BIG would have decreased CT scan utilization and neurosurgical consultation by 29%; this includes a 100% reduction in hospitalizations, RHCT, and neurosurgical consultation for BIG 1 patients and 97% reduction in BIG 2 patients without subsequent adverse events. While these cost savings are not widely generalizable, this study does demonstrate that BIG is a safe framework for management of TBI patients without routine use of RHCT and neurosurgical consultation.

How will this change my practice?
This is potentially a big (pun intended) shift in practice at many Level I and II Trauma centers, but it is an exciting opportunity to safely reduce resource utilization for patients with TBI, particularly since healthcare resources in many places are more constrained than ever. This is a promising framework which can be used to develop a similar pathway in collaboration with trauma and neurosurgical specialists.

Source
Validating the Brain Injury Guidelines: Results of an American Association for the Surgery of Trauma prospective multi-institutional trial. J Trauma Acute Care Surg. 2022 Aug 1;93(2):157-165. doi: 10.1097/TA.0000000000003554. Epub 2022 Mar 28.