Tag Archives: Prophylaxis

Brain Injury and Chemical Prophylaxis for DVT

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.

Related post: Does interrupting DVT prophylaxis increase risk for it?

Solid Organ Injury: How Soon Can We Begin Chemical DVT Prophylaxis?

Nonoperative management of solid organ injury is the norm, and has reduced the operative rate significantly. At the same time, the recognition that development of deep venous thrombosis (DVT) in trauma patients is commonplace creates uncertainty? Is it safe to give chemical prophylaxis with low molecular weight heparin (LMWH)? How soon after injury?

The trauma group at USC+LAC recently published the findings of a retrospective review of 312 patients undergoing nonoperative management for their liver, spleen or kidney injuries. They looked at chemical prophylaxis administration and its relationship to failure of nonop management of solid organ injury.

As expected, as the grade of the solid organ injury increased, so did the failure rate of nonoperative management. Administration of low molecular weight heparin, such as enoxaparin, did not increase failure rate in this study. All but one failure occurred in patients who had not yet received the injections. Likewise, two DVT and two pulmonary embolisms occurred, but only in patients who had not yet received prophylaxis. 

Bottom line: This small study offers some assurance that early prophylaxis is okay, and a few prospective studies do exist. UCSF / San Francisco General is comfortable beginning chemical prophylaxis 36 hours postop, regardless of solid organ injury. Look for more guidance on this issue in the coming year or so. Until then, consider starting LMWH prophylaxis early to avoid complications from DVT or PE.

Reference: Thromboembolic prophylaxis with low-molecular-weight heparin in patients with blunt solid abdominal organ injuries undergoing nonoperative management: current practice and outcomes. J Trauma 70(1): 141-147, 2011.

Does Interrupting DVT Prophylaxis Increase Risk for DVT/PE?

Deep venous thrombosis is a common concern in trauma care. Most trauma centers have well defined protocols for prophylaxis and surveillance. Ongoing use of pharmacologic thromboprophylaxis (PTP) in patients with traumatic brain injury (TBI), or in patients who need surgical procedures is controversial.  We have all experienced some form of “prophylaxis interruptus”, where our orthopedic or neurosurgical colleagues want us to forego or interrupt ongoing administration of heparin products. Does this create new problems?

A trial was conducted at two Denver trauma centers, trying to clarify the optimal administration of PTP in patients with stable TBI. One cohort received PTP, the other did not (either not indicated, short stay, or already on blood thinners). The group receiving PTP was also stratified into those who received it continuously and those who had interruptions in treatment.

They found that the incidence of DVT and PE was similar for patients receiving PTP vs those not receiving it. The two groups were very different, though, because the ones who did not receive it had less severe injuries and were more likely to be ambulating by discharge.  The most interesting finding was that being started on PTP and then interrupting it increased the incidence of DVT fourfold.

What is it about prophylaxis interruptus that is so risky? First, there were only 480 patients in this study, so statistical anomalies could be present. Could it be that the conditions (TBI) and operations that cause it to be interrupted greatly increase the risk? Unfortunately this study can’t answer those questions.

The bottom line: DVT and its prophylaxis is still a muddy concept. What we really need to do is to find out if PTP is really necessary in all the patients in whom we are using it. It would also be helpful if we knew how harmful it really is in patients with significant bleeding in their head, or in patients who need to undergo surgery. One alternative, if this paper pans out, is to begin with mechanical prophylaxis until cleared by neurosurgery and all operations are completed. For now, it’s not yet appropriate to change your existing practice and procedures.

Reference: Interrupted pharmocologic prophylaxis increases venous thromboembolism in traumatic brain injury. J Trauma 70(1):19-26, 2011.The term “prophylaxis interruptus” was coined by Tom Esposito in his discussion of this paper.