Tag Archives: TBI

Redefining Mild TBI: Who Needs To Be Transferred?

One of the more common reasons for transfer to a higher level trauma center these days is the “mild or minimal TBI.” Technically, this consists of any patient with a Glasgow Coma Scale score of 14 or 15. A transfer is typically requested for observation or neurosurgical consultation, or because the clinicians at the initial hospital are not comfortable looking after the patient.

Is this really necessary? With the number of ground level falls approaching epidemic proportions, transferring all these patients could begin to overwhelm the resources of high level trauma centers. The surgical group at Carolinas Medical Center examined their experience with a simple scoring system they designed to predict high risk minor TBI patients, and thus suitability for transfer. Here is their checklist:

Category A
  • Traumatic SAH
  • Tentorial or falcine SDH < 4mm thickn
  • Convexity SDH < 4mm thick
  • Solitary IPH < 1cm
  • Isolated intraventricular hemorrhage < 4mm
Category B
  • Any Category A lesion greater than the allowed size
  • Midline shift
  • Skull fracture
  • Compression of basal cisterns
  • Diffuse SAH or SAH involving basal cisterns
  • Subacute or chronic SDH
SAH = subarachnoid hemorrhage, SDH = subdural hemorrhage, IPH = intraparenchymal hemorrhage

Patients were considered to be low risk if they had only one or two category A lesions. If they had more than two, or any Category B lesions, they were higher risk and transfer was considered justified.

The authors retrospectively reviewed their experience with these patients over a three year period. They followed patients to see if they needed neurosurgical intervention, and evaluated the cost savings of avoiding selective transfers based on their criteria.

Here are the factoids:

  • A total of 2120 patients were studied, with 68% low risk and 32% high risk
  • Two of the low risk patients (0.14%)  ultimately required neurosurgical intervention, compared to 21% of high risk patients
  • Mean age (56), and patients taking anticoagulants or antiplatelet agents were the same in the two groups, about 2-3% for each
  • System saving by avoiding EMS transfer costs would have been $734K had the low risk patients been kept at the initial hospital

Bottom line: This study was presented as a Quick Shot paper at this year’s Eastern Association for the Surgery of Trauma meeting, so there are some key details missing. Was there an association between anticoagulation or antiplatelet agent and two failures in the low risk group? What were they, and what intervention did they require?

If this data holds up to publication, then it may provide a useful tool for deciding to keep minimal TBI patients at the local hospital. This is usually far more convenient for the patient and their family, but would require additional education of the clinicians at that hospital to help them become comfortable managing these patients. 

We use a similar tool within our Level I trauma center to decide which patients require a neurosurgical consultation. Since the low risk patients almost never require intervention, our trauma service provides comprehensive management while in hospital, and arranges for TBI clinic followup post-discharge. You can view and download a copy using the link below.

Link: Regions Hospital SAH/IPH/Skull fracture practice guideline

Reference: Redefining minimal traumatic brain injury (MTBI): a novel CT criteria to predict intervention. Quick Shot Paper #48, EAST 2019.

EAST 2019 #8: How To Keep Neurotrauma Patients At Level III Trauma Centers

Hospitals that do not have neurosurgical coverage are faced with a dilemma when they receive a head-injured patient. Do they automatically transfer to a higher level trauma center, or do they keep the patient? This is especially poignant in rural areas, where transfer times may be lengthy. If a patient doesn’t really have any significant pathology, they are likely to be evaluated at the receiving Level I or II center, then discharged all the way back home. But if they are kept at the initial hospital, there may be a nagging doubt about what happens if…

Five years ago, the group at University of Arizona – Tucson published a simple brain injury classification system that was designed to predict which injuries were likely to progress and need neurosurgical intervention. They called this system BIG for Brain Injury Guidelines. It was created and validated on a group of nearly 4,000 patients over four years, and the results have been promising. Since then, BIG has been validated using small study groups (<405) in pediatric head injury, and at Level I and III trauma centers.

Here’s the guideline:

One of the Quick Shot presentations at next week’s EAST Annual Scientific Assembly is another validation study at a Level III center in Lake Havasu City, Arizona that introduces one small modification to the guidelines. Normally, BIG is calculated after CT of the head is complete. This modification entailed BIG calculation after anticoagulation was reversed. Patients with BIG scores of 1 or two after reversal was complete were kept at the Level III, and were managed by the trauma surgeons. All BIG 3 patients were transferred to a higher level center.

Four years of trauma registry data were analyzed. During the first two years, patients with any positive BIG score were transferred. During the final two years, only patients who scored BIG 3 after reversal were moved.

Here are the factoids:

  • During the pre-BIG period, there were 72 transfers: 36 BIG-1, 23 BIG-2, and 13 BIG-3
  • Once the protocol was in place, there were 119 patients identified, 52 patients with BIG-1 or 2 who were kept and 67 BIG-3 patients who were transferred
  • 13 patients in the post-BIG time frame were excluded
  • None of the BIG-1 or 2 patients required transfer later
  • 39 of the 52 BIG-1 or 2 patients had repeat scans, and none worsened clinically, with an average hospital length of stay of 1.4 days
  • Estimated helicopter transport savings was $1.9M based on an average charge of nearly $50K per flight

The authors concluded that modified BIG could be used to triage neurotrauma patients for transfer, but cautioned that good clinical judgment should also be applied.

Here are some questions for the authors and presenter to consider in advance to help them prepare for audience questions:

  • Are you satisfied that BIG is sufficiently validated? To date, there are only a handful of validation studies and they have relatively small numbers.
  • Why did you choose to modify the score to wait until anticoagulation? Couldn’t this nullify the validation studies?
  • Do you have any practice guidelines in place to ensure consistent care of the patients you now keep at your center? Do they allow you to manage common problems like subarachnoid hemorrhage or intraparenchymal hemorrhage?
  • How did you ensure that your surgeons, hospitalists, and nurses were comfortable managing these neurotrauma patients? Did you have any educational sessions or other training for things like GCS monitoring and neuro exam?
  • How do you reverse anticoagulation, and how long does that usually take? Plasma and prothrombin complex concentrate are commonly used, but with vastly different reversal times. And what do you do about aspirin, clopidogrel, and the novel oral anticoagulants?
  • Why did you exclude 13 patients once you started using BIG?
  • Has your hospital administration provided any numbers regarding increased revenue from this practice? Your hospital is larger (171 beds), but this type of information will be vital for small, critical access hospitals.

This is very interesting work, and highly applicable to rural trauma centers!

References:

  • Successful management of select radiographic intracranial injuries in a rural trauma center without neurosurgeon coverage using a modified brain injury guideline. EAST 2019, Quick Shot Paper #6.
  • The BIG (brain injury guidelines) project: Defining the management of traumatic brain injury by acute care surgeons. J Trauma 76(4):965-969, 2014.

EAST 2019 #1: Predicting Outcome After Brain Injury

Here’s the first abstract I’ll review from the EAST 2019 Annual Assembly in January.

This one comes to us from the University of Arizona system, and specifically from Tucson. The senior author has an interest in traumatic brain injury (TBI) and geriatric trauma, so it’s not surprising to see this abstract that fuses the two. The aim was to create a new tool to predict mortality in patients who had sustained a TBI.

The authors devised a score, the Brain Trauma Outcome Score (BTOS) using three variables: age, injury severity score (ISS), and presence of blood transfusion. Furthermore, this was used to create a Brain Trauma Outcome Score (BTOS), by dividing the BTOS by the GCS. These equations were developed and tested using data sets from two years worth of TQIP data. I know, lots of acronyms, but stay with me. After generating the equations for GTOS and BTOS from one TQIP dataset and testing against another, both of these systems were checked for discriminatory power by generating receiving operator characteristic curves.

The authors found that the tested BTOS was better at predicting mortality than the tested GTOS. They concluded that “BTOS can accurately predict in-hospital mortality in all TBI patients.” Seems like a pretty bold assertion.

Here are some questions for the authors and presenter to consider in advance to help them prepare for audience questions:

  • Be aware that some typos crept into the final copy. When preparing abstracts, try not to use special characters (i.e. +) as they may not be generic enough for the commercial printing software used to prepare final copy. This is similar to avoiding video or links to YouTube videos in slide sets. I was able to figure out what the question marks really were (I think), but make sure the audience does, too.
  • Why did you even think to create this model? Some new “systems” are just wild guesses, and sometimes it’s even possible to find one that appears to have a significant correlation with reality. What was the rationale that prompted you to combine ISS, age, blood, and GCS? Did your clinical experience suggest this? Papers on related prediction systems? Then what?
  • Is validating your test data using other patients from the same dataset legitimate? Shouldn’t they be very similar since they are in the same 2-years of data? This could make the system less accurate when applied to a very different patient cohort.
  • The GCS range studied was very high and narrow. If I read the abstract correctly, the median was 14-ish with a range from 12-15. These are mostly mild TBIs, so why were they dying anyway? And if the formula for GTOS was derived using predominantly mild TBI data, how can it possibly work well for moderate and severe? And I still worry that patients were dying of problems unrelated to TBI.
  • Make sure you clearly explain your methods to the audience. Some are not well versed in ROC curves, and many will not understand the nuances and potential pitfalls of developing and validating numerical systems like this. It’s easy to lose them, so make sure you are clear and concise in your explanations.
  • How do you see a system like this being used in the future? It’s nice to have some appreciation of the practicality, and an assurance that this isn’t just an academic exercise.

I enjoyed the abstract, and look forward to hearing it in person next month!

Reference: The Brain Trauma Outcome Score (BTOS): Estimating mortality after a traumatic brain injury. EAST 2019, Paper #6.

Everything You Wanted To Know About: Cranial Bone Flaps

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.

Sports Drinks And Electrolyte Replacement In TBI

Yesterday, I wrote about the (lack of) effectiveness of forcing hypernatremia in the management of TBI. However, we do know that some of our head injured patients have trouble maintaining a normal sodium level, and if it drops quickly or too far, hyponatremia can certainly cause problems. Trauma professionals have a number of tools to help fix this, including salt supplements or tablets, saline infusions, or even hypertonic saline in more difficult cases.

But what about using a sports drink to replace electrolytes? Isn’t that what athletes do? There are quite a few of these sports drinks on the market, and new ones seem to appear every week. Common examples are Gatorade, Powerade, Muscle Milk, Vitamin Water, 10-K Thirst Quencher, and many more. What if your brain injured patients eschews the salt tabs and insists on pounding down sports drinks all day?

Here is a table from an old sports medicine paper that describes the composition of a number of sports drinks from back in the day. Some, like Gatorade, are still around. (Click image to see a bigger, readable version)

Note that the electrolyte results are in mg/250cc, so I will translate to meq/liter for you. Gatorade had the highest sodium concentration at the time, 20meq/L, and one of the lowest potassiums at 3meq/L. The majority of the current day sports drinks have about the same electrolyte composition. Note that they are all a bit hyperosmolar (300+ mOsm), and this is made possible by added carbohydrate from some type of sugar. The carb is usually in the form of sucrose, dextrose, and/or high fructose corn syrup (yum!).

Bottom line: Your typical sports drink is equivalent to D30 in 0.1 normal saline. Not good for your TBI patient when consumed for sodium supplementation. It will actually drive the serum sodium down when consumed in quantity. Make sure your patients steer clear of this stuff until their brain injury is healed and they are running their next marathon.

Reference: The Effectiveness of Commercially Available Sports Drinks. Sports Med 29(3):181-209, 2000.