In May, I wrote about a new direct thrombin inhibitor named dabigatran (Pradaxa). This drug appears beneficial for patients who need ongoing anticoagulation without the hassle of blood testing to check drug levels. The danger for trauma patients is that there is no antidote or rapid reversal possible. This means that significant traumatic bleeding, particularly in and around the brain, cannot be stopped! At Regions Hospital, we have seen a few patients on this drug, but luckily they have not had bleeding from trauma.
Late last month, Bristol-Myers Squibb and Pfizer announced that a new drug has shown very favorable results in preventing strokes in patients with atrial fibrillation (apixaban, Eliquis). Indeed, it cut the relatively low risk of stroke in half, compared to warfarin. It also had about a third fewer bleeding complications. It looks like it may also give dabigatran a run for its money.
This drug is a Factor Xa inhibitor, and also has no antidote other than time. There is some evidence that activated charcoal given orally within 3 hours of apixaban dosing may be somewhat helpful in reducing blood concentrations.
Trauma professionals need to be on the lookout for patients who use this drug. Any trauma patient who admits to being on a “blood thinner” needs to be questioned carefully to determine which one it is. If it is one of the newer drugs without an antidote, they need to be monitored continuously for signs of bleeding (read: ICU), especially if they have experienced head trauma.
Bottom line: Be on the lookout for these drugs. If any patients who have fallen are taking this drug (elderly, frequently intoxicated, etc.), contact their primary physician so that the risks vs benefits of continuing it can be considered.
I previously wrote about a new review that looked at using chemical prophylaxis for deep venous thrombosis (DVT) in patients with traumatic brain injury (TBI). The authors showed that it was safe to give subcutaneous heparin products within 24 to 48 hours after a stable 24 hour followup CT.
A just-published article now helps to refine the selection of the heparin product. A retrospective review looked at 386 ICU patients with a head Abbreviated Injury Score (AIS) > 2. A total of 57 received mechanical prophylaxis, the remainder received heparin products. Chemical prophylaxis consisted of subcutaneous enoxaparin 30mg bid or unfractionated heparin 5000u tid, at the whim of the attending neurosurgeon.
The heparin group had a slightly but significantly higher Head AIS (4.1 vs 3.8). The drugs were started at the same time post-injury, about 48 hours from admission. Unfractionated heparin was found to be inferior to enoxaparin. The unfractionated heparin patients had both a higher rate of pulmonary embolism, and were more likely to have progression of any intracranial hemorrhage (12% vs 5%). The authors claim a significantly lower DVT rate, but information in their data tables do not support this. Additionally, their overall DVT rate is very low, most likely because they did not routinely screen for it.
Bottom line: The head injury / DVT prophylaxis literature is expanding rapidly. It’s time to start working with your neurosurgeons to initiate chemoprophylaxis early (within 48 to 72 hours from injury once any intracranial bleeding is stable). And it looks like the drug of choice is enoxaparin, not unfractionated heparin.
Reference: Safety and efficacy of heparin or enoxaparin prophylaxis in blunt trauma patients with a head abbriviated injury severity score >2. J Trauma 71(2):396-400, 2011.
Traumatic brain injury (TBI) is one of the leading causes of death from trauma worldwide. The assessment of TBI was revolutionized in 1976 when the GCS scale was first introduced. Shortly after its introduction, it was found to be predictive of outcome after brain injury. But it does have some drawbacks: it is somewhat complicated, and interrater reliability is low.
Interestingly, a number of studies have shown that the motor component of GCS is nearly as accurate as the full score in predicting survival. Thus, the Simplified Motor Score (SMS) was introduced as a possible substitute for the GCS in 2007. It was found to be equivalent for predicting survival when applied in the ED.
Obeys commands = 2
Localizes pain = 1
Withdraws (or less) to pain = 0
So can this scale be validated in the field when applied by prehospital providers?
Nearly 10 years of data (almost 20,000 patients) from the Denver Health trauma registry was analyzed to attempt to validate SMS when used by EMS. Although the statistics were not perfect, they found that GCS and SMS were equivalent for predicting the presence of a brain injury, need for emergency intubation, need for neurosurgical intervention, and death. Interestingly, they found that both SMS and GCS were not quite as good at predicting overall outcomes as previously thought.
Bottom line: The simplified motor score is a simple system that has now been shown to be as accurate as GCS in predicting severity and outcome from head injury. To be clear, though, neither is a perfect system. They must still be combined with clinical and radiographic assessments to achieve the best accuracy. But SMS can and should be used both in-hospital and prehospital to get a quick assessment, and may help determine early intervention and need for activating the trauma team.
Assessment of coma and impaired consciousness: a practical scale. Lancet 2:81-84, 1976.
Assessment and prognosis of coma after head injury. Acta Neurochir (Wien) 34:45-55, 1976.
Validation of the simplified motor score in the out-of-hospital setting for the prediction of outcomes after traumatic brain injury. Ann Emerg Med, in press, Aug 2011.
Deep venous thrombosis (DVT) and its complications are recognized and common problems in trauma patients, particularly those with traumatic brain injury (TBI). We know that giving chemical prophylaxis like heparin and low molecular weight heparin (LMWH) reduces the risk. Unfortunately, trauma professionals (and neurosurgeons in particular) are reluctant to give it after acute TBI for fear of making intracranial hemorrhage worse.
Froedtert Hospital in Milwaukee modified their protocol for TBI patients to allow chemical prophylaxis to start 24 to 48 hours after a 24 hour followup CT that showed no progression of any bleeding. Therefore, prophylaxis could be started 48 to 72 hours after injury. They used subq heparin three times daily, or LMWH twice daily. All others received mechanical prophylaxis and were screened twice weekly by duplex ultrasound. The chemical prophylaxis group was not screened routinely.
A total of 812 patients were studied, half of whom received early prophylaxis per protocol. The average Abbreviated Injury Score for the head in these patients was 3.4, which represents fairly serious injury. There was a significant decrease in the incidence of DVT in the chemical prophylaxis group (1% vs 3%). More intriguing, there was a lower rate of injury progression in this group as well (3% vs 6%), although not quite statistically significant.
Bottom line: Although this is a small and retrospective study, it was well designed and relatively large compared to most other similar work. It shows that use of chemical prophylaxis works in patients with serious TBI, and appears to be safe. Similar protocols should be considered by trauma program multidisciplinary operations committees to further systematize this process.
Reference: Safety and efficacy of prophylactic anticoagulation in patients with traumatic brain injury. J Am Coll Surg 213:148-154, 2011.
Public awareness of concussions, particular those from sports, is on the rise. It’s difficult enough for trauma professionals to diagnose some of the milder forms of head injury. Expecting lay people to do this is just not realistic.
Most people have heard of ImPACT testing for head injury. This involves determining a player’s baseline ability to remember a series of words. It tests memory, attention span and reaction time. A baseline study is required, and the test takes about 20 minutes to administer using a computer.
The King-Devick test is a numerical processing tool that can be administered using an iPad or a deck of cards. A baseline value is required as well, and the test takes about 2 minutes to administer. See the video for details.
Both tests have been validated by a number of scientific studies, and both are only available for purchase. Several hospitals, trauma centers, and schools have purchased the programs and will administer them for free.
Check out these valuable programs and consider providing them at your own local sporting events.