Tag Archives: head injury

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The Modified Brain Injury Guideline Criteria (mBIG)

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In my previous post, I reviewed the Brain Injury Guideline criteria (BIG) that were published in 2014, and cited some early papers promoting its use for simplifying neurotrauma care. These criteria allowed trauma professionals to use our neurosurgical colleagues’ services more sensibly.

As a reminder, these are the original BIG criteria:

Some revisions were proposed in 2020 to improve patient safety and reproducibility further.  Here are the revised criteria:

So, what are the differences?

  • The “loss of consciousness” was changed to a more objective assessment, the GCS
  • Intoxication is defined as a blood alcohol concentration > 80 mg/dL
  • Aspirin and NSAIDs are not considered antiplatelet agents
  • Epidural hematoma (EDH) is no longer sized; any epidural moves the patient to mBIG 3
  • Multiple intraparenchymal hemorrhages (IPH) move the patient to mBIG 3
  • Subarachnoid hemorrhage is more objectively classified

The mBIG criteria were tested in a multi-institutional review comparing the original criteria with the modified criteria. BIG 3 patients were excluded, since these patients required admission and neurosurgical consultation, which is maximal therapy. All patients underwent repeat CT scans to monitor for progression of the injury.

Here are the factoids:

  • A total of 269 patients were included; 98 were BIG 1 and 171 were BIG 2
  • In both BIG 1 and BIG 2 cohorts, CT progression was seen in about 11% of patients. These patients tended to have more severe injuries overall and were more likely to have EDH or IPH.
  • Two BIG 2 patients decompensated and required neurosurgical intervention; both had EDH

These findings prompted the changes that are now part of the mBIG score. Here is the complete algorithm based on the mBIG criteria (click to see full-size):

A larger validation study was published in 2022 by the same authors, following the addition of 496 patients from the same three trauma centers. The total number of patients included in the study was 496.

More factoids:

  • There were now a total of 223 mBIG 1 patients and 273 mBIG2
  • The number of CT scans and neurosurgery consults was significantly decreased
  • Hospital length of stay was also significantly decreased

Bottom line: The mBIG criteria perform better and are at least as safe as the initial BIG criteria. The mBIG criteria are more objective, making it easier to stratify patients accurately. 

The mBIG criteria should be adopted by any center seeking a consistent and validated process for stratifying patients for observation, admission, or neurosurgical consultation following head trauma. This will conserve resources and allow our neurosurgical colleagues to focus on the patients who truly need them.

References:

  1. Multicenter assessment of the Brain Injury Guidelines and a proposal of guideline modifications. Trauma Surgery & Acute Care Open, 5(1), e000483.
  2. A multicenter validation of the modified brain injury guidelines: Are they safe and effective?. Journal of Trauma and Acute Care Surgery 93(1):p 106-112, July 2022.
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The BIG Brain Injury Guidelines

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Until five years ago, there was tremendous variability in the way brain injuries were managed at trauma centers. There were no clear guidelines describing what should be done during the initial evaluation, and no consensus as to when to involve neurosurgery. This resulted in a lot of flailing about and unnecessary calls to our neurosurgical colleagues.

Then the Brain Injury Guidelines (BIG) came along 15 years ago. They were developed to allow trauma programs to stratify head injuries in such a way as to better utilize resources such as hospital beds, CT scanning, and neurosurgical consultation.

Injuries are stratified into three BIG categories, and management is based on them. Here is the stratification algorithm:

And here is the management algorithm based on the stratification above:

(RHCT = repeat head CT)

The original study was published ten years ago and was a retrospective review of 4,000 patient records. It found that a significant number of these patients could be managed exclusively by the trauma surgeons.

The AAST BIG Multi-Institutional Group set about prospectively validating this system to ensure that it was accurate and safe. They identified adult patients from ten high level trauma centers that had a positive initial head CT scan. They looked at the the need for neurosurgical intervention, change in neuro exam, progression on repeat head CT, any visits to the ED after discharge, and readmission for the injury within 30 days.

Here are the factoids:

  • About 2,000 patients were included in the study, with BIG1 = 15%, BIG2 = 15%, and BIG3 = 70% of patients
  • BIG1: no patients worsened, 1% had progression on CT, none required neurosurgical intervention, no readmits or ED visits
  • BIG2: 1% worsened clinically, 7% had progression on CT, none required neurosurgical intervention, no readmits or ED visits
  • All patients who required neurosurgical intervention were BIG3 (20% of patients)

The authors concluded that using the BIG criteria, CT scan use and neurosurgical consultation would have been decreased by 29%.

Bottom line: This is an exciting paper! BIG has been around for awhile, and some centers have already started using it for planning the management of their TBI patients. This study provides some validation that the system works and keeps patients safe while being respectful of resource utilization. 

My only criticism is that the number of patients in the BIG1 and BIG2 categories is low (about 600 combined). Thus, our experience in these groups remains somewhat limited. However, the study is very promising, and more centers should consider adopting BIG to help them refine their management of TBI patients. 

This was the first prospective study of the BIG criteria. A great deal of additional work has been done. And now, an attempt has been made to simplify this algorithm even further.

In my next post, I’ll review the modified BIG (mBIG) criteria and describe them in detail.

References:

  1. The BIG (brain injury guidelines) project: defining the management of traumatic brain injury by acute care surgeons. Journal of Trauma and Acute Care Surgery, 76(4), 965-969.
  2. 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.
General

Antiplatelet Therapy And Blunt Head Trauma

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All trauma professionals are aware of the evils of anticoagulation in patients who sustain traumatic brain injury. Warfarin is one of the most common anticoagulants encountered, but there is also a growing number of poor outcomes in patients with the newer, non-reversible agents.

But what about antiplatelet agents like aspirin and clopidogrel (Plavix)? Many physicians worry about these drugs, but is it warranted? Two Level I trauma centers in the Chicago area reviewed their experience. They retrospectively reviewed the records of patients over 40 years old who sustained blunt head trauma. A total of 1547 patients were identified over a 4 year period. They analyzed these records for in-hospital mortality, need for neurosurgical intervention, and length of stay.

Here are the factoids:

  • 27% of patients were taking antiplatelet agents. Patients also taking warfarin were excluded.
  • 21% were taking aspirin alone, 2% clopidogrel alone, and 4% both drugs
  • Patients taking the drugs averaged about 10 years older than those who were not
  • Overall, injury severity was relatively low (average ISS 10). A disproportionate number of more severely injured patients were not taking antiplatelet agents.
  • There was no difference of incidence of intracranial hemorrhage (45%), neurosurgical intervention (3%), or mortality (6%) between the two groups
  • Hospital length of stay averaged about 6.5 days, but long LOS was a bit more common in the antiplatelet agent group.

Bottom line: This is one more in a series of papers scrutinizing trauma and antiplatelet agents. A few previous studies have shown an adverse effect, but they have been much smaller series. I don’t believe the jury is in yet, so watch these patients carefully. A 6 or 12 hours repeat scan is probably in order, along with frequent neuro monitoring.  It’s probably not worthwhile to actively try to reverse them by giving platelets unless there is obvious life-threatening hemorrhage or sudden neurologic change (see below).

Related posts:

Reference: Outcomes in traumatic brain injury for patients presenting on antiplatelet therapy. Am Surg 81(2):128-132, 2015.

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Trauma 20 Years Ago: Seatbelt Injuries

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Seatbelt use has increased from 58% in 1994 to a high of 85% last year. We know that seatbelt use saves lives, but trauma professionals are also aware that they can create their own injuries as well. This is a positive trade-off, because belt use prevents injuries that are difficult to treat (e.g. severe brain injury) and produces a higher number of intra-abdominal injuries that are easy to treat.

The spectrum of injuries attributed to seat belt use was finally appreciated in a journal article published 20 years ago this month. The authors wanted to catalog the various injuries seen in belted and unbelted motor vehicle occupants. They reviewed data from the North Carolina Trauma Registry, one of the most sophisticated state registries at the time. Although there were over 21,000 records in the database, only 3,901 involved motor vehicle crashes and had complete data on seatbelt use.

This study found the following:

  • Mortality was higher in those not wearing their seat belts (7% vs 3.2%)
  • Unbelted had a much higher incidence of severe head injury (50% vs 33%)
  • Overall incidence of any abdominal injury was the same for both (14%)
  • GI tract injuries were more common in the belted group (3.4% vs 1.8%)
  • Solid organ injury was the same

Bottom line: This study sparked the recognition that seatbelts reduce severe head injury but increase the incidence of some hollow viscus injuries. About 514 severe head injuries were prevented in exchange for 21 additional abdominal injuries that were generally easily repaired. Good tradeoff!

Related posts: 

Reference: The spectrum of abdominal injuries associates with the use of seat belts. J Trauma 31(6):821-826, 1991.

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Controlling Fever In Head Injury

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Fever is a well recognized side effect of head injury. Management of fever is inconsistent among physicians taking care of these patients. There is a lot of debate on the best course of action, but not so much data. Current enthusiasm for applications of hypothermia has created some reluctance to tolerate much in the way of hyperthermia. Here is my take on the currently available literature.

First, understand that there is a fundamental difference between studies that study induced hyperthermia vs those that look at spontaneous fever. This lies in the fact that the set point for temperature regulation is changed in fever, but not in hyperthermia. Therefore, it is not clear whether hyperthermia studies can truly be used to answer these questions.

Animal studies originally focused on stroke models, which showed deleterious effects from hyperthermia. TBI is very different than stroke, but some hyperthermia models did tend to show cellular damage and blood brain barrier breakdown at temperatures of 39C. However, a fever model in rats showed no outcome difference (in rats) in febrile vs normothermic animals with TBI.

A Medline search (ref 4) yielded no randomized controlled trials that could be used to guide us with regard to fever management. The lesser quality papers involved a very heterogeneous group of subjects that made it difficult to draw good conclusions. As a generalization, they found that extremes of temperature, both high and low, were probably associated with worse outcomes. One randomized prospective study showed that aggressive fever control for temperatures > 38.5C had higher mortality and more infections.

A recent meta-analysis (ref 3) found that TBI patients with fever stayed in the hospital and ICU longer. This translated into an extra $14,000 per patient. Precise reasons for the longer stay cannot be accurately determined, but it might be expected that patients with fever would undergo time-consuming searches for possible infectious sources.

Finally, a very recent prospective study (ref 1) at a single institution that did not try to alter temperature found that the optimum survival occurred in a group of patients whose temperatures remained between 36.5 and 38C.

Bottom line: Literature support for aggressive management of fever is poor. If there were a clear correlation with temperature maintained at or slightly below normal, we’d probably have figured it by now. Fever up to 38 degrees C probably does not need to be treated in head injured patients. However, this does not eliminate the need to continue surveillance for infectious complications.

References:

  1. The effect of spontaneuous alterations in brain temperature on outcome: a prospective observational cohort study in patients with severe traumatic brain injury. J Neurotrauma 27(12):2157-2164, 2010.
  2. Induced normothermia attenuates intracranial hypertension and reduces fever burden after severe traumatic brain injury. Neurocrit Care 11(1):82-87, 2009.
  3. Brain injury and fever: hospital length of stay and cost outcomes. J Intensive Care Med 24(2):131-139, 2009.
  4. The significance of altered temperature after traumatic brain injury: an analysis of investigations in experimental and human studies: part 2. Br J Neurosurg 22(4):497-507, 2008.