All posts by TheTraumaPro

EAST 2017 #2: CT Scan After Recent Operative Exploration for Penetrating Trauma

The general rule for penetrating trauma, especially gunshots to the abdomen, is that you don’t need to obtain a CT scan to help you decide to go to the OR. (Of course, there are a few exceptions.) And the corollary has always been that you don’t need to get a CT scan after you operate for penetrating trauma.

But the group at UCSF is questioning this. They retrospectively looked at 5 years of data on patients who underwent trauma laparotomy without preoperative imaging. They focused on new findings on CT that were not reported during the initial operation.

Here are the factoids:

  • 230 of 328 patients undergoing a trauma lap did not have preop imaging
  • 85 of the 230 patients (37%) underwent immediate postop CT scan. These patients tended to have a gunshot mechanism and higher injury severity score.
  • Unreported injuries were found in 45% (!) and tended to be GU and orthopedic in nature
  • 47% of those with unreported injuries found required some sort of intervention

Bottom line: This is a very interesting and potentially practice changing study. However, there is some opportunity for bias since only select patients underwent postop scanning. Nevertheless, one in five patients who did get a postop scan had an injury that required some sort of intervention. This study begs to be reworked to further support it, and to develop specific criteria for postop scanning.

Questions/comments for the authors/presenters:

  • Be sure to break down your results by gunshot vs stab. This will help formulate those criteria I mentioned above.
  • Specifically list the occult injuries and interventions required. In some studies, those “required interventions” are pretty weak (urology consult vs an actual procedure).
  • How exactly did the operating surgeons determine who to send to CT? Was it surgeon-specific (i.e. one surgeon always did, another never did)? Was it due to operative findings (hole near the kidney)? This is also needed when developing specific criteria for postop imaging.
  • Nice poster!

Click here to go the the EAST 2017 page to see comments on other abstracts.

Related posts:

Reference: Routine tomography after recent operative exploration for penetrating trauma: what injuries do we miss?  Poster #14, EAST 2017.

EAST 2017 Page on The Trauma Pro Blog

Hello all! I’ve created a separate page for posts regarding the upcoming meeting of the Eastern Association for the Surgery of Trauma.

I will be reviewing a baker’s dozen abstracts over the next 2 weeks, giving my own analysis and commentary. I’ll also provide some suggestions and questions to anticipate for the authors to refer to.

Click here to visit the EAST 2017 page!

And if you are a presenter and would like me to look at your paper, just email, tweet, or connect via your method of choice.

EAST 2017 #1: Accuracy of CT Scans Done Outside The Trauma Center

Imaging prior to transfer to a trauma center has been the subject of debate for years. The focus has primarily been on the necessity of these scans, and the sheer numbers that are done. For the most part, the discussion has been driven by the potential for radiation exposure.

This paper, from the University of Oklahoma, takes a different approach. The authors looked at the accuracy and adequacy of imaging performed prior to transfer to their Level I trauma center.

Patients were enrolled prospectively over an 8 month period in 2012. Outside images were interpreted by a single radiologist who was blinded to the outside interpretation.  If images were repeated, they were compared to the first scan, and the reason for the redo was noted.

Here are the factoids:

  • 235 consecutive transfer patients were enrolled, and 203 who had at least one CT scan were included in the final dataset
  • 76% of these patients had additional imaging performed once they arrived at the trauma center
  • Reasons for additional images were insufficient workup (76%) and technical inadequacy (31%)
  • Missed injuries were detected on outside CT scans 49% of the time, and the majority of them (90%) were deemed clinically significant
  • Missed injuries on a repeated scan were present in 54% of patients, and 76% were clinically significant
  • Overall, 73% of images (either outside or repeat) contained additional injuries

Bottom line: This is a new approach to assessing the value of outside imaging prior to transfer to a trauma center. I have always recommended that trauma centers work with their referral partners to assure them we don’t need them to do the workup for us. I encourage them to obtain only what they need to decide if they can keep the patient. But once they find anything that they cannot treat, stop all workup and prepare to transfer.

Questions/comments for the authors/presenters:

  • Why did you use such an old dataset?
  • Is this a prospective enrollment/retrospective analysis study designed to use an existing, old dataset?
  • How did you decide that outside imaging represented an inadequate workup? Do you have a diagnostic imaging guideline that you follow?
  • What are the credentials for your trauma radiologist?
  • How did you determine that a missed injury was clinically significant? Be sure to provide a list and explanation during your presentation.
  • Be sure to separate out missed injuries seen on the original CT from new missed injuries seen on the repeat scan.
  • Congratulations on looking at an old problem in a new way!

Click here to go the the EAST 2017 page to see comments on other abstracts.

Related posts:

Reference: Adequacy and accuracy of non-tertiary trauma center computed tomography: what are we missing? Paper #7, EAST 2017.

The Best of EAST! Starts tomorrow!

Starting tomorrow, and continuing through the annual meeting of the Eastern Association for the Surgery of Trauma, I will be analyzing one of the upcoming presentations each day. That’s 13 papers, and I’ll be picking some of the notable ones.

Remember, abstracts are teasers to get you to read/listen to the full paper. I’ll be reviewing them in detail, putting them into context, and this year I’ll be providing a list of questions that the presenters should be prepared to field from the audience. And I’ll be in that audience, so I will probably ask a few of them!

Enjoy the commentary, and I’ll see many of you at EAST in sunny Hollywood, Florida!

Enoxaparin And anti-Xa Levels: Who Cares? Part 3

Today is the final installment in a series about the use of anti-Factor Xa levels to titrate enoxaparin dosing to prevent venous thromboembolism (VTE). This is another study that tries to show that “hitting the number” actually makes a difference in patient care. You decide.

This study identified a subset of patients at high-risk for VTE based on a commonly used and very good risk screening tool, the Risk Assessment Profile (RAP). It takes some 17 factors into account to arrive at a numerical score. In this paper, the authors chose a score of 10 or greater to denote high risk. The patients were all seriously injured, and were in the trauma ICU of this established Level I trauma center.

This retrospective study excluded non-ICU patients, ones who did not receive enoxaparin or anti-Xa levels, and two patients with DVT on admission. This brought the number of eligible patients from 621 to 127 (the treatment group). They then narrowed the field down to the high-risk treatment group by excluding patients with a RAP score < 10. Now we are down to 86. But then 30 more (35%) were excluded because they did not undergo duplex ultrasound screening, leaving only 56 to study (!).

The control group was a “similar” historical cohort from a two year period from 2009 to 2012. You can tell that this group is getting a little stale, because the only patients included were those who received unfractionated heparin for prophylaxis (remember those days?). Of the 106 patients in the control group, 20 (28%) were reported as have VTE. However, it included 6 patients with DVT on admission, which were excluded in the study group. This makes the DVT rate look higher in the control group. It also included 2 upper extremity DVT and 1 septic pelvic venous thrombosis. Excluding all of these brings the historical VTE rate down to only 10%. Remember this.

So let’s get on to the factoids:

  • Only 35% of the 127 patient treatment group “hit the number” for anti-Xa (0.2-0.4 IU/ml) after three 30mg doses of enoxaparin
  • An additional 25% managed to achieve the desired anti-Xa level after dose adjustment, but 51 patients (40%) never did get there
  • There were 10 VTE events in the 127 treatment group patients, 9 of whom had high RAP scores, giving them a 7.8% rate of VTE
  • Nine of the 10 VTE patients occurred in patients with low anti-Xa levels
  • The authors compared their 7.1% DVT rate with the 21% in their historical controls, concluding that titrating anti-Xa levels reduced this rate. They did not include PE for some reason, and do not claim a statistical difference. They admit that the study was underpowered to detect differences in VTE. There is no significant difference in VTE rates in the study or control groups.

Bottom line: This is the last paper on the topic. I promise. At least for a while. Here’s what we know:

  • VTE is a problem in trauma patients, particularly seriously injured ones
  • We are not very good at sticking to a prophylaxis or screening regimen (note how many patients are excluded in all of these studies)
  • We can’t seem to generate the numbers to conduct a good study that can detect differences in what we do
  • It’s difficult to “hit the number” for anti-Xa using standard enoxaparin dosing
  • We don’t even know if it makes a difference if we do “hit the number”. VTE rates seem to be the same regardless.

So we are struggling to make a lab test look right to adjust enoxaparin dosing, and we don’t even know if it makes a difference. Will somebody put a good, multi-center study together and help us to figure all of this out?

Related posts:

Reference: Anti-Xa-guided enoxaparin thromboprophylaxis reduces rate of deep venous thromboembolism in high-risk trauma patients. J Trauma 81(6):1101-1108, 2016.