Tag Archives: AAST2019

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.

Abstracts, Complications

AAST 2019 #2: Predicting Abdominal Operation After Blunt Trauma – The RAPTOR Score

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Patients with blunt abdominal injury, particularly those with seat belt signs, can be diagnostically very challenging. If the patient is stable and does not have peritonitis, CT scan is typically the first stop after the trauma resuscitation room. As many trauma professionals know, the radiographic findings can be subtle and/or not very convincing.

The trauma group at the University of Tennessee in Memphis sought to identify specific findings that might help us better identify patients that will need laparotomy. They retrospectively identified all their mesenteric injuries over a five-year period. A single blinded radiologist (is this an oxymoron or not?) reviewed all 151 patient images who underwent laparotomy, looking for predictors of bowel or mesenteric injury.  All of the predictors were then converted into a scoring system called RAPTOR (radiographic predictors of therapeutic operative intervention; kind of a stretch?). These predictors were then subjected to multivariate regression analyses to try to tease out if there were any independent predictors of injury.

Here are the factoids:

  • A total of 151 patients were identified over the 5 year period; 114 underwent laparotomy
  • Of the 114 operated patients, two thirds underwent a therapeutic laparotomy and the other third were nontherapeutic
  • There no missed injuries in the non-operated patients
  • The components of the RAPTOR score were culled from all the potential findings, and were determined to be
    • Multifocal hematoma
    • Acute arterial extravasation
    • Bowel wall hematoma
    • Bowel devascularization
    • Fecalization (of what??)
    • Free air
    • Fat pad injury (??)
  • Linear regression then showed that only three of these, extravasation, bowel devascularization, and fat pad injury to be independent predictors of injury
  • If three or more RAPTOR variables were present, then the sensitivity, specificity, and positive predictive values for injury were 67%, 85%, and 86%, and an area under the receiver operating characteristic curve (AUROC) of 0.91

The authors concluded that the RAPTOR score provided a simplified approach to detect patients who might benefit from early laparotomy and not serial abdominal exams. They go further and say it could potentially be an invaluable tool when patients don’t have clear indications for operation.

It looks like there are two things going on here at the same time. First, a new potential scoring system is being piloted. And second, a regression analysis is being used to examine the data as well. 

But first, let’s back up to the beginning. This is a retrospective study, with a relatively small size. This makes it far harder to ensure that the results will be significant, or at least meaningful. Use of a single radiologist can also be problematic, especially since many of the CT findings with this mechanism of injury are subtle. 

The reported performance of the RAPTOR score is a bit weak. The listed statistics show that it accurately identified only two thirds of those who needed an operation and 85% of those who didn’t. The AUROC for the regression is very good, though. Could a good old-fashioned serial exam scenario be better?

Bottom line: It will be interesting to hear the background on RAPTOR vs regression, and find our how the authors will use or are using these tools.

Here are my questions for the presenter and authors:

  • Why did you decide to create a scoring system that uses a set of variables that may be dependent on each other? Isn’t the regression equation better?
  • Has this information changed your practice? It seems that the two of the three regression variables are fairly obvious reasons to operate (active extravasation and devascularization). Do you really need the rest?
  • Has this study helped you decrease the non-therapeutic laparotomy rate for blunt abdominal injury?
  • And please define fecalization and fat pad injury!

I’m looking forward to hearing this presentation!

Reference: RADIOGRAPHIC PREDICTORS OF THERAPEUTIC OPERATIVE INTERVENTION AFTER BLUNT ABDOMINAL TRAUMA: THE RAPTOR SCORE. AAST 2019 Oral Paper 6.

 

Abstracts

Coming Up! AAST 2019 Abstract Reviews!

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It’s that time of year again. The 2019 Annual Meeting of the American Association for the Surgery of Trauma (AAST) is only two weeks away! I’ll be selecting a number of interesting abstracts (oral, poster, and perhaps a few quick shots) to review here.

My focus will be on abstracts that offer new information or interesting insights into old problems. I’ll pick them apart, looking at their strengths and weaknesses. Finally, after rendering my opinion of their import, I’ll list a number of questions for the authors or presenter to consider. Who knows, they may be asked some of them at the meeting?!

Enjoy, and feel free to provide your own comments here!