All posts by TheTraumaPro

How To Predict Venous Thromboembolism In Pediatric Trauma

As with adults a decade ago, the incidence of venous thromboembolism (VTE) in children is now on the rise. Whereas adult VTE occurs in more than 20% of adult trauma patients without appropriate prophylaxis, it is only about 1% in kids, but increasing. There was a big push in the early 2000′s to develop screening criteria and appropriate methods to prevent VTE. But since the incidence in children was so low, there was no impetus to do the same for children.

The group at OHSU in Portland worked with a number of other US trauma centers, and created some logistic regression equations based on a large dataset from the NTDB. The authors developed and tested 5 different models, each more complex than the last. They ultimately selected a model that provided the best fit with the fewest number of variables.

The tool consists of a list of risk factors, each with an assigned point value. The total point value is then identified on a chart of the regression equation, which shows the risk of VTE in percent.

Here are the factors:

Note that the highest risk factors are age >= 13, ICU admission, and major surgery.

And here is the regression chart:

Bottom line: This is a nice tool, and it’s time for some clinical validation. So now all we have to do is figure out how much risk is too much, and determine which prophylactic tools to use at what level. The key to making this clinically usable is to have a readily available “VTE Risk Calculator” available at your fingertips to do the grunt work. Hmm, maybe I’ll chat with the authors and help develop one!

Reference: A Clinical Tool for the Prediction of Venous Thromboembolism in Pediatric Trauma Patients. JAMA Surg 151(1):50-57, 2016.

Bedrest After Pediatric Liver/Spleen Injury? Really?

A set of guidelines for management of blunt solid organ injury in children developed by the American Pediatric Surgical Association was originally published in 1999. One of the elements of the guideline was to place the child on bedrest for a period of time after the injury. Arbitrarily, this period was defined as the injury grade plus one day. So for a grade 3 spleen injury, the child would have to stay in bed for 4 days (!).

A paper published in 2013 looked at the impact of shortening this time interval. Over a 6 year period, all pediatric liver and spleen injuries from blunt trauma were identified and an abbreviated bedrest protocol was implemented. For low grade injuries (grade 1-2), children were kept in bed for 1 day, and for higher grade injuries this was extended to 2 days.

Here are the factoids:

  • 249 patients were enrolled (about 40 per year) with an average age of 10. “Bedrest was applicable for 199 patients, 80%.” Huh? Does that mean that 50 patients were excluded due to surgeon preference?
  • The organ injured was about 50:50 for spleen vs liver. Twelve children injured both.
  • Mean injury grade was 2.7, which is fairly high
  • Mean bedrest was 1.6 days, and mean hospital stay was 2.5
  • Bedrest was the limiting factor for hospital stay in 62% of cases
  • There were no delayed complications of the injury

Bottom line: Come on! Most centers don’t keep adult patients at bedrest this long, and we learned about solid organ injury management from kids! Children almost never fail nonop management, so why treat them more restrictively than adults? And have you ever tried to keep a child at bedrest? Impossible! This study is too underpowered to give real statistically valid results, but it certainly paints a good picture of what works. We recently updated our adult and pediatric protocols to eliminate bedrest and npo status. Let’s get rid of these anachronisms once and for all!

Reference: Follow up of prospective validation of an abbreviated bedrest protocol in the management of blunt spleen and liver injury in children. J Ped Surg 48(12):2437-2441, 2013.

A New Way To Repair Damaged Muscle?

For patients with severely damaged skeletal muscles, the best way to heal them is a combination of splinting and physical therapy, right? These serve to increase the size of existing muscle fibers. And a few cellular therapies are also available involving stem cells or stimulating their production, which may actually add new muscle. But what about something cheaper and less complicated?

Researchers at the engineering school at Harvard are working on a new approach, mechanotherapy. They tried two therapeutic interventions in mice with hindleg muscle damage and ischemia. 

The first was implantation of a magnetic gel pack directly in contact with the muscle. A magnet placed on the other side of the muscle was pulsed to repeatedly squeeze the muscle gently.

The second group had a small pneumatic cuff placed which encircled the leg (a tiny mouse BP cuff?). If was inflated cyclically to massage the muscle.

Both therapies resulted in a 2.5x increase in muscle regeneration and less scarring and fibrosis, compared to control animals that had neither therapy.

Left image: control animal. Right image: mechanotherapy. Note the increased muscle cell density.

Bottom line: Unfortunately, we typically think about medicine from a chemical standpoint. That’s why we are so reliant on drugs for just about everything. But this study suggests that merely squeezing the muscle regularly and early after injury may greatly improve healing. There are significant implications for trauma patients, of course. Might it also be possible to help decrease muscle mass loss in denervated muscles, as in para- and quadriplegics? And we may find that if we combine this with some of the biologics already in use, the results may be even better. Stay tuned for developments.

Related post:

Reference: Biologic-free mechanically induced muscle regeneration. Proc Natl Acad Sci USA 113(6):1534-1539, 2016.

March Trauma MedEd Newsletter Is Coming!

Finally! After a bit of a delay, the issue on REBOA is being released to subscribers this weekend. Here is what you will find inside:

  • Everything You Always Wanted To Know About REBOA
  • What Is REBOA?
  • Who is REBOA For?
  • How Is REBOA Performed?
  • What Are The Results For REBOA?
  • What’s The Bottom Line?

Subscribers will receive it over the weekend; everyone else will have to wait until the end of next week.

Subscribe now and be sure to get it first!  So sign up for early delivery now by clicking here!

Pick up back issues here!

Comparison of Cervical Spine Stabilization

A reader recently asked what the optimal method for inline stabilization is. We’ve been pondering this question for nearly 30 years. In 1983, trauma surgeons at UCLA looked at a number of devices available at that time and tested them on normal volunteers. They measured neck motion to see which was “best.”

Here’s what they found:

  • Soft collar – In general, this decreased rotation by 8 degrees but insignificantly protected against flexion and extension. Basically, this keeps your neck warm and little else.
  • Hard collars – A variety of collars available in that era were tested. They all allowed about 8% flexion, 18% lateral movement, and 2% rotation. The Philadelphia collar allowed the least extension.
  • Sandbags and tape – Surprisingly, this was the best. It allowed no flexion and only a few percent movement in any other direction.

The Mayo clinic compared four specific hard collars in 2007 (Miami J, Miami J with Occian back, Aspen, Philadelphia). They found that the Miami J and Philadelphia collars reduced neck movement the best. The Miami J with or without the Occian back provided the best relief from pressure. The Aspen allowed more movement in all axes.

And finally, the halo vest is the gold standard. These tend to be used rarely and in very special circumstances.

Bottom line:

  • For EMS: Rigid collar per your protocol is the standard. In a pinch you can use good old tape and sandbags with excellent results.
  • For physicians: The Miami J provides the most limitation of movement. If the collar will be needed for more than a short time, consider the well-padded Occian back Miami J (see below).

References:

  • Efficacy of cervical spine immobilization methods. J Trauma 23(6):461-465, 1983.
  • Range-of-motion restriction and craniofacial tissue-interface pressure from four cervical collars. J Trauma 63(5):1120, 1126, 2007.