Tag Archives: TBI

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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.
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Everything You Wanted To Know About: Cranial Bone Flaps

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Patients with severe TBI frequently undergo surgical procedures to remove clot or decompress the brain. Most of the time, they undergo a craniotomy, in which a bone flap is raised temporarily and then replaced at the end of the procedure.

But in decompressive surgery, the bone flap cannot be replaced because doing so may increase intracranial pressure. What to do with it?

There are four options:

  1. The piece of bone can buried in the subcutaneous tissue of the abdominal wall. The advantage is that it can’t get lost. Cosmetically, it looks odd, but so does having a bone flap missing from the side of your head. And this technique can’t be used as easily if the patient has had prior abdominal surgery.

2. Some centers have buried the flap in the subgaleal tissues of the scalp on the opposite side of the skull. The few papers on this technique demonstrated a low infection rate. The advantage is that only one surgical field is necessary at the time the flap is replaced. However, the cosmetic disadvantage before the flap is replaced is much more pronounced.

3. Most commonly, the flap is frozen and “banked” for later replacement. There are reports of some mineral loss from the flap after replacement, and occasional infection. And occasionally the entire piece is misplaced. Another disadvantage is that if the patient moves away or presents to another hospital for flap replacement, the logistics of transferring a frozen piece of bone are very challenging.

4. Some centers just throw the bone flap away. This necessitates replacing it with some other material like metal or plastic. This tends to be more complicated and expensive, since the replacement needs to be sculpted to fit the existing gap.

So which flap management technique is best? Unfortunately, we don’t know yet, and probably never will. Your neurosurgeons will have their favorite technique, and that will ultimately be the option of choice.

Reference: Bone flap management in neurosurgery. Rev Neuroscience 17(2):133-137, 2009.

Abstracts

Best Of EAST 2024 #9: The Burden Of Transferred TBI Patients

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In theory, tiered trauma centers should allow patients with lesser injuries to be treated at lower levels and more severe trauma at higher-level centers. This parallels the resource availability at those centers. In reality, many patients with injuries that seem complex (solid organ, children, and TBI) are transferred due to a “lack of comfort” in taking care of them or the perception that they may deteriorate quickly.

The truth is that many, if not most, of these patients are discharged shortly after transfer to the higher-level center, with minimal intervention. This burdens the trauma system in several ways. First, trauma professionals at the lower-level centers slowly lose their skills and comfort in taking care of these patients. The prehospital system is already plagued with low resources and a shortage of personnel. Using one of the only ambulances in a rural area for transport to a distant center takes it out of the community, potentially putting the area population at risk for delayed care.

The University of Arizona at Tucson group performed another TQIP study to highlight this problem. They performed a four-year retrospective analysis of transfer data in patients with isolated TBI with intracranial hemorrhage. They observed the number of transferred patients who required CT scans, ICP monitoring or craniotomy/craniectomy, length of stay, and mortality.

Here are the factoids:

  • Of the nearly 120,000 patients with isolated TBI at Level I and II centers, 45% were transferred from other centers
  • Most patients had GCS 14-15 on arrival, but 10% had GCS 8
  • CT was performed in 58%, and another repeat CT in 4%
  • Four percent underwent ICP monitoring, and 12.5% had a crani
  • Mortality was 6.5%
  • Median length of stay was two days, with a range of 1-5
  • 18% were discharged within 24 hours, and 39% within 48 hours

The authors concluded that, while half of isolated TBI patients were treated at high-level trauma centers, one-third were discharged home within 48 hours with no intervention other than a CT scan. They recommend systemwide guidelines to improve resource utilization.

Bottom line: This straightforward analysis highlights one of the most significant issues facing trauma systems: unnecessary transfer. For decades, Level I and II centers were convenient and always available for transfer, even if the indications were questionable. Then COVID came along and changed everything.

Now, resources are tight everywhere. EMS is underpaid and under-reimbursed, and personnel are difficult to recruit. Hospital personnel of all types face low staffing levels, making it more stressful to provide the level of care we are accustomed to. Skilled nursing facilities, rehab centers, and other outpatient care settings face the same problems.

This has created a domino effect, where the lower-level centers want to transfer a patient but can’t find a bed at the higher-level centers. When they do, it takes forever to get them transported. Then, the higher-level centers can’t discharge them if they need any level of care other than home care.

There are many pieces to this puzzle, but this abstract clearly outlines one of them. Lower-level centers are transferring some patients who could actually be admitted to them. Several reasons may be given, but it typically boils down to the surgeons or the hospitalists not being “comfortable” with certain patients or worrying that they could deteriorate.

This paper does not tease out what kind of isolated TBI the patients had, and I recommend they do. There is a big difference in patients with a subarachnoid hemorrhage (SAH) vs. those with an epidural. The number of patients with SAH is far greater, and the vast majority can go home after a brief (or no) observation. The likelihood of deterioration in patients not on blood thinners is nearly zero. 

State trauma systems and higher-level trauma centers should work with their Level III and IV partners to adopt consistent practice guidelines and protocols to stratify these patients to identify those at low risk. The higher-level centers should provide education to help their referral partners develop a baseline comfort level with these patients. This is the only way we can begin to realign the levels of trauma centers with the levels of care needed by our patients.

Reference: Endless highways: the burden of transferred traumatic brain injury patients in the United States. EAST 2024, Podium paper #42.

Abstracts, Complications, Head

Best Of EAST 2023 #12: VTE Prophylaxis In Severe TBI

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Time for another abstract on venous thromboembolic disease (VTE) prophylaxis, but this time in patients with severe head injury. VTE is a significant problem for trauma patients. Those with a potential source of bleeding from their injuries cause us to hesitate and consider the timing of chemical prophylaxis closely. Do we really want to cause more bleeding?

This is particularly problematic with intracranial hemorrhage, as the treatment is major brain surgery. Over recent years, the literature has been leaning toward earlier prophylaxis as soon as the intracranial blood has stopped evolving.

The EAST Multicenter Trials Group performed a seven-year retrospective review at 24 Level I and II trauma centers to assess the safety and efficacy of VTE chemoprophylaxis.  They divided patients into three groups: no prophylaxis, early prophylaxis (within 24 hours), and late prophylaxis (after 24 hours).

The authors assessed two endpoints: VTE occurrence and expansion of intracranial hemorrhage (ICH). They used several regression models to check their hypotheses.

Here are the factoids:

  • A total of 2,659 patients met the inclusion criteria. This averages out to 15 eligible patients per month per center. This is probably reasonable when combining a few high-volume centers with more lower volume centers.
  • Compared to early prophylaxis, patients who received late prophylaxis were twice as likely to develop VTE, although this was not statistically significant (p = 0.059)
  • Compared to early prophylaxis, patients who received no prophylaxis were a third less likely to develop VTE, although this, too, was not statistically significant (p = 0.39
  • About 25% of patients who received either early or late prophylaxis suffered an extension of their ICH, but only 17% of the no-prophylaxis group did
  • The regression model showed that the no prophylaxis group was 36% less likely to develop ICH extension compared to either early or late prophylaxis groups.

The workgroup concluded that the development of VTE was not dependent on the timing of the start of prophylaxis. Furthermore, patients who did not receive any prophylaxis had significantly decreased odds of ICH extension. The group recommended larger randomized studies to extend this work.

Bottom line: Shocker! This multicenter study suggests that the no prophylaxis and early prophylaxis groups had fewer VTE events than the late group, although these results were not statistically significant. This means that there wasn’t an advantage to giving the shot.

And the other major conclusion was that both early and late prophylaxis was associated with a significantly higher incidence of ICH extension. 

Roll these together, and you will find that neither early nor late prophylaxis help prevent VTE, yet they are both associated with additional bleeding in and around the brain! 

Heresy! I am trying to figure out what to make of these results. Perhaps the retrospective nature of the study and the wildcards this introduces influenced the results. It could be a study power problem, except the numbers were approaching significance that was unfavorable for prophylaxis.

I will be very interested to hear how the authors explain these findings. And yes, a well-powered randomized study would be great, but I don’t think many institutional review boards will be keen on a no-treatment group given our current fear of VTE. So don’t count on any real answers soon.

Reference: EARLY VTE PROPHYLAXIS IN SEVERE TRAUMATIC BRAIN INJURY: A PROPENSITY SCORE WEIGHTED EAST MULTICENTER TRIAL. EAST 2023 Podium paper #38.