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Philosophy

The Tenth Law Of Trauma

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Several years ago, I ran a series of posts on my Laws of Trauma. I assembled them into  newsletter that contained all nine that existed at the time. If you’d like to download it, just click this link.

I’ve  been struck by another pattern, and I think it’s about time to add the tenth law. Weirdly enough, it was inspired by Dancing With The Stars. You’ll see what I mean.

Here is the Tenth Law of Trauma:

“In trauma, it generally takes two to tango”

So what does this mean? When dealing with injury, there are a few broad quantitative categories.

  • Single person mechanism. This is one extreme. Common examples would be the elderly fall, a single vehicle car crash, or a self-inflicted stab or gunshot. There is a single “point of failure” that only the individual involved can manage, but for various reasons they do not or cannot. This law does not apply.
  • Multiple person mechanism. This is the other extreme, and thankfully is not seen very often at all. Examples are a tour bus crash, house explosion, or mass casualty event. Once again, those involved usually have little ability to recognize or avoid the imminent event, and the tenth law is null and void.
  • Two person mechanism. This one is very common, and is exemplified by the two car crash, pedestrian struck, or the various flavors of assault. And this is the one that the tenth law applies to.

When two people are involved in an event that leads to traumatic injury, there is usually (but certainly not always) a set of checks and balances that is present. And frequently there is at least one opportunity to avoid the event.

In the case of a two vehicle crash, one driver may have “gone off the reservation” and ignored the usual traffic laws for whatever reason. But the second driver usually has an opportunity to recognize this and change their behavior in order to avoid the situation. However, if they are distracted, impaired, or making assumptions about how other driver behave they can still get into trouble. Thus, it takes two.

What about the pedestrian struck? Likewise, the driver or the pedestrian may have done something nonstandard. Wear dark clothes at night. Glance at their phone while driving. Look at their passenger a bit too long while having a conversation. Once again, the other participant may have an opportunity to see the result of this unexpected behavior and jump or swerve out of the way.

Interpersonal violence it a bit more tricky. Sure, one of the potential participants may get wind that something is up and try to avoid or defuse the situation. But not always. And this situation is heavily charged with emotion and social pressures and is much more difficult to change or avoid.

Bottom line: Many, but certainly not all,  “two-person” mechanisms of injury are avoidable if both of the individuals involved are mentally present and attentive to their surroundings. Look at your own patient population and see how often this applies. You may be surprised!

Complications

More On Lead Poisoning And Retained Bullets

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Trauma professionals frequently have to leave bullets in patients. It is often more disruptive to go digging the projectiles out than to just leave them in place. But patients always want to know why and what the consequences might be.

In my last post, I discussed a very old paper on what we know about lead levels and retained bullets. Very recently, a meta-analysis was published that provides a better picture of this topic. They somehow managed to find over 2000 articles dealing with lead toxicity and bullets out there. But after someone had the pleasure of reviewing each of them, they found only 12 that had any meaningful or actionable information.

Here are the factoids:

  • All studies were observational (duh! It would be difficult to get your IRB to approve a study where patients were shot on purpose)
  • There were five cross-sectional studies, four case-control studies, and three prospective cohort studies
  • The studies were small, with a median of only 26 patients (range 15-120)
  • Eleven of the twelve studies showed an association with retained bullets and elevated blood lead levels
  • Three studies showed elevated blood levels if a fracture was present
  • The higher the number of retained fragments, the more likely lead levels were to be high
  • Higher lead levels were associated with retained fragments near a bone or joint
  • There were no good correlations with number of fragments and location vs actual lead toxicity

Bottom line: Even using meta-analysis, it is difficult to tease out meaningful answers to this question. That speaks to the low numbers of papers and their quality. However, this study does provide a little bit of guidance.

Retained bullet fragments are probably not a big worry in most patients. The bothersome cases are those where the fragments are in or near a bone or joint. And even though few patients actually developed lead toxicity, lead levels approaching 5 micrograms/dL can have physiologically significant negative effects. 

Recommendation: If your patient has a retained bullet fragment near a bone or joint, or they have “multiple” retained fragments (no good definition of this), they should have blood lead levels measured every three months for a year. If the level is rising, and certainly if it reaches the 5μ/dL level, attempts should be made to remove the fragments.

Reference: Lead toxicity from retained bullet fragments: A systematic review and meta-analysis. J Trauma 87(3):707-716, 2019.

Complications

Can Lead Poisoning Occur After A Gunshot?

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This is a fairly common question from victims of gunshots and their families. As you know, bullets are routinely left in place unless they are superficial. It may cause more damage to try to extract one, especially if it has come to rest in a deep location. But is there danger in leaving the bullet alone?

One of the classic papers on this topic was published in 1982 by Erwin Thal at Parkland Hospital in Dallas. The paper recounted a series of 16 patients who had developed signs and symptoms of lead poisoning (plumbism) after a gunshot or shotgun injury. The common thread in these cases was that the injury involved a joint or bursa near a joint. In some cases the missile passed through the joint/bursa but came to rest nearby, and a synovial pseudocyst formed which included the piece of lead. The joint fluid bathing the projectile caused lead to leach into the circulation.

The patients in the Parkland paper developed symptoms anywhere from 3 days to 40 years after injury. As is the case with plumbism, symptoms were variable and nonspecific. Patients presented with abdominal pain, anemia, cognitive problems, renal dysfunction and seizures to name a few.

Bottom line: Any patient with a bullet or lead shot that is located in or near a joint or bursa should have the missile(s) promptly and surgically removed. Any lead that has come to rest within the GI tract (particularly the stomach) must be removed as well. If a patient presents with odd symptoms and has a history of a retained bullet, obtain a toxicology consult and begin a workup for lead poisoning. If levels are elevated, the missile must be extracted. Chelation therapy should be started preop because manipulation of the site may further increase lead levels. The missile and any stained tissues or pseudocyst must be removed in their entirety.

Granted, this is a very old paper. Over the years, a few papers on the topic have popped up from time to time. In my next post, I’ll review a meta-analysis on this topic that was just recently published.

Reference: Lead poisoning from retained bullets. Ann Surg 195(3):305-313, 1982.

Abstracts, Thorax

AAST 2019 #8: Timing Of Thoracic Aortic Injury Repair

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Over the past two decades, there has been a massive swing from open repair of blunt thoracic aortic injury to thoracic endovascular aortic repair (TEVAR). Although technically a bit more complex, it has decreased both morbidity and mortality significantly. The usual push in fresh trauma patients is to take care of all the life-threatening injuries as soon as possible. And from the days of the open thoracic procedure, this was generally warranted.

However, the optimal timing of repair during the age of TEVAR is not as clear. Is it really necessary to go crashing into the angio or hybrid suite to get this taken care of? Or should it wait until the patient is not as physiologically damaged? The group at University of Texas at San Antonio looked at experience in the National Trauma Databank for some guidance. They reviewed four years of data from 2012 to 2015. Patients who arrested in or prior to arrival in the ED were excluded. Mortality was the primary outcome of interest, but complications and hospital length of stay (LOS) was also noted.

Here are the factoids:

  • Nearly 6,000 patients with blunt thoracic aortic injury were identifed, and 1,930 (33%) underwent TEVAR, 2% were opened, and 65% were managed nonoperatively
  • Looking only at TEVAR patients, 69% underwent the procedure within 24 hours, 24% after 24 hours, and the remainder were not recorded (!)
  • Mortality was significantly higher in the early TEVAR group (6.4% vs 2.1%)
  • Hospital LOS was significantly shorter in the early TEVAR group (18 vs 22 days)
  • Logistic regression controlling for hypotension, severe TBI, ISS and older age confirmed the significantly lower mortality in the delayed group

The authors concluded that delayed (>24 hrs) TEVAR was associated with decreased mortality but longer length of stay.

This is a nice, clean abstract to read. The hypothesis and results are easy to understand and make sense. And it’s exactly the kind of poster that makes you think a bit. 

The only real downside is that it is an NTDB study, so there is very limited ability to go back and tease out why these results should be true. These results should push the authors to set up a more prospective study so they can figure out why this should be true. We can certainly speculate that it helps to temporize with good blood pressure control while cleaning up other major injuries and correcting deranged physiology. But one never knows until the right study is actually done.

Here are my questions for the presenter and authors:

  • Were you able to glean any insights into the associations you identified from the other data in the NTDB records you used? This could help design a really good study to see if your impressions are true.
  • The fact that a quarter of patients had TEVAR at an unknown time throws a big monkey wrench in your results. Can you use any statistical tricks to see if assuming they were either early or late would influence your results. Is it possible that this unknown group could completely neutralized your study?

I’m very excited by this one, and I don’t normally get too excited by posters. Great work!

Reference: Timing of repair of blunt traumatic thoracic aortic injury: results from the National Trauma Databank. AAST 2019, Poster #5.

Abstracts

AAST 2019 #7: Trauma Surgeon Fatigue And Burnout

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I love this topic, especially since I’m getting a bit long in the tooth myself. The impact of night call is significant, even if it’s less noticeable in my younger colleagues. Theories (and some real data) abound that long stretches of stressful work is unhealthy and may lead to burnout. Modifications such as reduced call length or varying work type have been tried, but there is little data showing any real effect.

The trauma group at Grant Medical Center in Columbus, Ohio performed a month-long prospective study involving six Level I trauma centers. They set out to monitor fatigue levels  due to varying call shift schedules and duration, and to see if they could identify any relationship to risk of surgeon burnout.

The authors used an actigraphy type device to monitor fatigue using an unspecified alertness model. These devices are typically worn on the wrist, and have varying levels of sophistication for determining sleep depth and fatigue. The surgeons self-reported their daily work activities as “academic”, “on-call”, “clinical non-call”, or “not working” and the lengths of time for each. A validated burnout inventory was taken at the end of the study to gauge burnout risk. The impact of 12 vs 24 hour call shifts was judged based on these variables.

Here are the factoids:

  • The number of surgeons involved in the study was not reported (!!!)
  • Mean  and worst fatigue score levels were “significantly worse” after a 24 hour shift compared to 12 hours
  • The proportion of time spent with a fatigue level < 70 (“equivalent to a blood alcohol of 0.08%”) was significantly longer during 24 hours shifts (10% vs 6% of time)
  • There was no real correlation of call shift length or times spent in various capacities on the burnout score
  • Pre-call fatigue levels correlated well with on-call fatigue, but not working pre-call did not

The authors concluded that fatigue levels relate to call length and correlate strongly with fatigue going into the call shift. They also noted that the longer shifts brought fatigue levels to a point that errors were more likely. They did not find any relationship to burnout.

There are a lot of things here that need explanation. First, the quality of the measurement system (actigraph) is key. Without this, it’s difficult to interpret anything else. And the significance data is hard to understand anyway. 

The burnout information is also a bit confusing. Other than putting an actigraph on the surgeons and having them log what they were doing, there was no real intervention. How can this possibly correlate with burnout?

The authors are trying to address a very good question, the relationship between call duration, configuration, fatigue, and error rates. More importantly, but less studied in trauma professionals, is the impact of disrupted sleep on the health and longevity. These are very important topics and I encourage the authors to keep at it!

Here are my questions for the presenter and authors:

  • Please provide some detail about the device used for actigraphy and exactly what was measured. There is substantial variation between devices, and very few are able to show sleep disturbance as well as actual brain wave monitoring. If this information is not extremely well-validated, then all of the results become suspect.
  • How many subjects actually participated, and how can you be sure your fatigue score differences are really statistically significant? It’s difficult for me to conceive that a difference of only 3.7 points on the “fatigue level scale” from 83.6 to 87.3 is significant. This is especially relevant since the abstract states that a score < 70 is similar to a blood alcohol level of 0.08%. The average level is well above that. And does statistical significance confer clinical significance?
  • And how about more info on the burnout inventory used? I presume the surgeons didn’t suddenly just start taking call for a month. They’ve been doing it for years. So why would a month of monitoring give any new indication of the possibility of burnout. It would seem that the usual surgeon lifestyle across this group is not leading to burnout. And I’m not sure this is accurate.

Reference: More call does not mean more burnout: a multicenter analysis of trauma surgeon activity with fatigue and burnout risk. AAST 2019, Oral abstract 52.