The February 2019 Trauma MedEd Newsletter Is Here!

Welcome to the current newsletter. This issue is devoted to an uncommon yet somewhat troubling problem, fat embolism. Here are some of the things I cover:

  • Fat Embolism vs Fat Embolism Syndrome (FES)
  • Clinical Manifestations Of FES
  • Diagnosis Of Fat Embolism Syndrome
  • FES And Orthopedic Surgery
  • Prevention And Treatment Of Fat Embolism Syndrome

The March issue will be released to subscribers late this month and will cover a potpourri of interesting little tidbits. I’ll release it to everyone via this blog in April, so subscribe now if you want it sooner!

To download the current issue, just click here! Or copy this link into your browser: http://bit.ly/TME201902.

Prehospital Use Of The ABC Score And MTP

Early and appropriate resuscitation is critical in any severely injured trauma patient. Typically, the trauma team assesses the patient upon arrival and makes a determination as to what type of resuscitation fluids are most appropriate. If blood is judged to be necessary, individual units can be given, or the massive transfusion protocol (MTP) can be activated.

I’ve previously written about two objective methods to assist in the decision to activate your MTP, shock index (SI) and assessment for blood comsumption (ABC). These have traditionally been applied once the patient arrived. What would happen if you used prehospital information to calculate the ABC score and were able to activate your MTP sooner rather than later?

The group at the University of Colorado in Aurora studied this concept. The charge nurse captured information to calculate the ABC score from the initial prehospital information received by phone while the patient was enroute. He or she would then activate the MTP in order to have blood products delivered as close to patient arrival as possible.

They reviewed their experience over a 29-month period. The first 15 months used their original system, calculating ABC on arrival and then deciding whether to activate MTP. During the final 14 months, it was calculated prior to patient arrival and the MTP was “pre”-activated when the score was 2 or more. The primary outcome studied was mortality, and secondary variables were appropriate activation of MTP, and adherence to balanced resuscitation ratios.

Here are the factoids:

  • A total of 119 patients with hypotension and/or MTP activation were studied; 24 occurred pre-implementation and 95 post
  • Pre-implementation, 63% of 24 hypotensive patients had MTP activation and only 6 (40%) received blood. Only 2 patients (33%) had RBC:FFP ratios between 1:1 and 2:1.
  • Post-implementation, 98% of hypotensive patients had MTP activation, a 6-fold increase
  • Also post-implementation, 42% of the activations received the blood, and balanced product ratios increased to 77%
  • Overall mortality decreased from 42% to 19% after implementation, all of which occurred in the penetrating injury group
  • Hospital and ICU lengths of stay were unchanged and there were no readmissions

Bottom line: The authors actually rolled two studies into one here. The main focus of the paper was to look at use of ABC score using prehospital information, but they also changed their MTP setup at the same time. During the initial part of the study, they did not have thawed plasma available, so the first cooler contained only red cells. Plasma was delivered when available, usually about 45 minutes after the first cooler had arrived. Post-implementation, thawed plasma was included in the first cooler.

So is the reduction in mortality (only in penetrating injury) due to early availability of the entire cooler, or because the desired product ratios were much more consistently met? Unfortunately, we can’t know.

This is a relatively small study, but the results with respect to blood actually being given, attainment of ratios, and mortality are impressive. Is the takeaway message to activate MTP early based on prehospital info or to make sure all coolers stock plasma? My take is that it’s probably best to do both!

Related posts:

Reference: Effect of pre-hospital use of the assessment of blood consumption score and pre-thawed fresh frozen plasma on resuscitation and trauma mortality. JACS 228:141-147, 2019.

ABC: A Quick & Dirty Way to Predict Massive Transfusion

It’s nice to have blood available early when major trauma patients need it. Unfortunately, it’s not very practical to have several units of O neg pulled for every trauma activation, let alone activate a full-blown massive transfusion protocol (MTP). Is there any way to predict which trauma patient might be in need of enough blood to trigger your MTP?

The Mayo Clinic presented a paper at the EAST Annual Meeting several years ago that looked at several prediction systems and how they fared in predicting the need for massive transfusion. Two of the three systems (TASH – Trauma Associated Severe Hemorrhage, McLaughlin score) are too complicated for practical use. The Assessment of Blood Consumption tool is simple, and it turns out to be quite predictive.

Here’s how it works. Assess 1 point for each of the following:

  • Heart rate > 120
  • Systolic blood pressure < 90
  • FAST positive
  • Penetrating mechanism

A score >=2 is predictive of massive transfusion. In this small series, the sensitivity of ABC was 89% and the specificity was 85%. The overtriage rate was only 13%.

The investigators were satisfied enough with this tool that it is now being used to activate the massive transfusion protocol at the Mayo Clinic. Although the abstract is no longer available online, it appears to be remarkably similar to a paper published in 2009 from Vanderbilt that looks at the exact same scoring systems. Perhaps this is why it never saw print? But the results were the same with a sensitivity of 75% and a specificity of 86%.

Here’s a summary of the number of parameters vs the likelihood the MTP would be activated:

ABC Score         % requiring massive transfusion
0                                1%
1                               10%
2                               41%
3                               48%
4                             100%

Bottom line: ABC is a simple, easy to use and accurate system for activating your massive transfusion protocol, with a low under- and over-triage rate. It doesn’t need any laboratory tests or fancy equations to calculate it. If two or more of the parameters are positive, be prepared to activate your MTP, or at least call for blood!

In my next post, I’ll look at the impact of using ABC based on prehospital information.

Related post:

References: 

  • Comparison of massive blood transfusion predictive models: ABC, easy as 1,2,3. Presented at the EAST 24th Annual Scientific Assembly, January 26, 2011, Session I Paper 4. (No longer available online)
  • Early prediction of massive transfusion in trauma: simple as ABC (assessment of blood consumption)?J Trauma 66(2):346-52, 2009.

More On CSF Rhinorrhea/Otorrhea

 

Trauma professionals worry about stuff. Like just about everything, really. Sometimes we have good guidance (research) to help us decide what to do. Many times, we don’t. Management of rhinorrhea and otorrhea from CSF leak after trauma is definitely one of those things.

I’ve seen a variety of treatments used in these patients over the years. Is it really a CSF leak? Let’s get a beta-2 transferrin test (see below). Can’t the patient get meningitis? Their may be concomitant sinus fracture and bacterial contamination, so why not give antibiotics? Or vaccinate them?

The Cochrane library contains a vast number of reviews of common clinical questions. One of those questions just happens to be the utility of giving prophylactic antibiotics in patients with basilar skull fracture. Interestingly, they’ve been reviewing and re-reviewing this question about every 5 years, since 2006. During the three reviews done, there have been no additional research papers published on the topic.

Here are the factoids:

  • Studies that specifically examined the use of prophylactic antibiotics in patients with basilar skull fracture were reviewed. All included meningitis as one of the outcome parameters.
  • There were only 5 high quality (randomized, controlled) trials, with a total of 208 participants
  • There were an additional 17 lower quality trials published, but no conclusions could be reached from them due to methodology problems
  • In the high quality trials, there were no differences in the incidence of meningitis, mortality, or meningitis-related mortality
  • There were no specific adverse effects related to antibiotic administration. But one of the high quality studies did note a shift to higher counts of pathologic bacteria in the posterior nasopharynx in the antibiotic group.
  • No studies on the use of meningitis vaccinations exist. A survey of UK physicians showed that 35% recommend at least one vaccine, typically for Strep Pneumo.

Bottom line: There is still no good evidence to support the use of prophylactic antibiotics or meningitis vaccination in patients with CSF leak from uncomplicated basilar skull fracture. When you see surveys that show some physicians promoting a treatment and others doing nothing, it means there is most likely no significant benefit. If there were a big difference, we would have seen it by now! And giving drugs (antibiotics, vaccines) that have no proven use is expensive and can always lead to unexpected complications. 

References:

  • Immunisations and antibiotics in patients with anterior skull base cerebrospinal fluid leaks. J Laryngol Otol 128(7):626-629, 2014.
  • Antibiotic prophylaxis for preventing meningitis in patients with basilar skull fractures. Cochrane Database Syst Rev April 28, 2015.

Tips For Taking Care Of CSF Leaks

The management of CSF leaks after trauma remains somewhat controversial. The literature is sparse, and generally consists of observational studies. However, some general guidelines are supported by large numbers of retrospectively reviewed patients.

  • Ensure that the patient actually has a CSF leak. In most patients, this is obvious because they have clear fluid leaking from ear or nose that was not present preinjury. Here are the options when the diagnosis is less obvious (i.e. serosanguinous drainage):
    • The “halo” or “double ring sign” is a form of pillow chromatography. The blood components separate from the CSF as they move through the pillow fabric, creating a clear ring or halo surrounding a bloody spot. This is the cheapest, fastest test and is actually fairly reliable.
    • High resolution images of the temporal bones and skull base. If an obvious breach is noted, especially if fluid is seen in the adjacent sinuses, then a CSF leak is extremely likely.
    • Glucose testing. CSF glucose is low compared to serum glucose.
    • Beta 2 transferrin assay. Don’t do it!! This marker is very specific to CSF. However, the test is expensive and results may take several days to a few weeks to receive. Most leaks will have closed before the results are available, making this a poor test.
  • Place the patient at bed rest with the head elevated. The basic concept is to decrease intracranial pressure, which in turn should decrease the rate of leakage. This same technique is used for management of mild ICP increases after head injury.
  • Consider prophylactic antibiotics carefully. The clinician must balance the likelihood of meningitis with the possibility of selecting resistant bacteria. If the likelihood of contamination is low and the patient is immunocompetent, antibiotics may not be needed.
  • Ear drops are probably not necessary. They may confuse the picture when gauging resolution of the CSF leak.
  • Wait. Most tramatic leaks will close spontaneously within 7-10 days. If it does not, a neurosurgeon or ENT surgeon should be consulted to consider surgical closure.

References:

  1. Brodie HA, Thompson TC. Management of complications from 820 temporal bone fractures. Am J Otol, 1997;18:188-197.
  2. Brodie HA. Prophylactic antibiotics for posttraumatic cerebrospinal fluid fistulas. Arch Otolaryngol Head, Neck Surg. 123:749-752.