All posts by TheTraumaPro

Best of AAST #9: Popliteal Atery Injury Repair

Injury of the popliteal artery is potentially devastating. Since this vessel is essentially and end artery, any complication resulting in thrombosis can result in limb loss. Traditionally, significant injuries have been treated with open repair and/or bypass. However, endovascular therapies have been making inroads in this area. Short-term outcomes appear to be equivalent. But what happens in the long term? Is one better than the other?

Scripps Mercy in San Diego (yes, same as yesterday’s abstract!) performed a retrospective review of the same California state discharge database. This time, they focused on patients with popliteal artery injury, and the attendant complications of fasciotomy and amputation. They stratified the patients into open and endovascular groups.

Here are the factoids:

  • 769 patients with popliteal artery injury were identified over an 8-year period
  • 59% were managed with an open operation, 4% using endovascular techniques, 2% combined, and 34% nonoperatively
  • Fasciotomies were performed significantly more often in the open group (41% vs 19%)
  • More amputations were performed in open cases, but this was not significantly different (11% vs 3% [1 patient in the endovascular group])
  • Embolism or thrombosis was significantly more likely during the first admission in endovascular or combined endo/open cases
  • Patients requiring both endo and endo+open procedures  were 5x more likely to undergo a later amputation, and 4x more likely to die after discharge

Bottom line: First, remember the limitations of this study: (very) small numbers, and a large database that precludes teasing out details. It suggests that open repair of popliteal injury is superior to endovascular due to higher thrombosis/embolism and amputation rates. Performing a fasciotomy is somewhat subjective, and may be done by surgeon preference to protect the limb. But amputation is more objective.

Unfortunately, we will not get anything more definitive any time soon. This 8-year analysis of a huge state database yielded only 769 cases, or 96 per year. In a state with 39 million people. That’s three injuries (reported) per million people per year. We will never generate a study that will tell us the full answers. But in the meantime, consider endovascular repair of popliteal artery injury only in patients for whom an open procedure is more challenging or risky (e.g. obesity, associated wounds).

Reference: Outcomes for popliteal artery injury repair after discharge: a large-scale population-based analysis. Session XXII Paper 55, AAST 2018.

Best of AAST #8: Complications After Trauma Laparotomy

With the introduction of damage control laparotomy (DCL) in the early 1990s, the trauma literature has focused on the nuances of this procedure. A significant amout of research has looked at patient selection, techniques, optimum time to closure, and complications afterwards. Studies on the single-look trauma laparotomy (STL) seem to have fallen behind. When compared to DCL, it seems to have relatively few complications.

But is that really so? A paper from the 1980s showed a nearly 50% complication rate after STL, but this included some trivial things like atelectasis which padded the numbers. A group at Scripps Mercy in San Diego looked at long-term complications after  STL in a state-wide California database. They were able to identify patients who underwent STL who were then readmitted for complications at a later date. They studied this data over an 8-year period.

Here are the factoids:

  • A total of 2,113 patients had a STL during the study period
  • One third (712) were readmitted at least once, with a median time to first readmission of 110 days
  • 30% of these patients had a surgery-related complication:
    • bowel obstruction 18%
    • infection 9%
    • incisional hernia 7%
  • Mechanism of injury was not related to development of complications

Bottom line: More than 10% of patients undergoing single-look trauma laparotomy develop significant complications. This is much higher than the complication rate seen after typical general surgical procedures. The difference between these groups and the reasons are not clear. Additional work must be done to tease out the risk factors, and our patients should be counseled on these potential complications and when to return for evaluation. Finally, the trauma surgeon should always use their best judgment to avoid an unnecessary trauma laparotomy.

Reference: Long-term outcomes after single-look trauma laparotomy: a large population-based study. Session IV Paper 14, AAST 2018.

Best of AAST #7: What’s New With Reboa

Despite all you read about it these days, REBOA is still very new. The first papers describing use in humans are barely 5 years old! A few select centers have been early adopters and are publishing a regular flow of research on their experience.

But we need more numbers! Many trauma centers have considered, or actually adopted the use of REBOA already. However, we are still working out a lot of the nuts and bolts of this very invasive procedure. The group at University of Arizona – Tucson reviewed the national experience over a two year period by massaging the data in the Trauma Quality Improvement Program (TQIP) database. All Level I-III trauma centers in the US are required to report their experience to this large, detailed collection of trauma data.

They performed a retrospective review of REBOA vs non-REBOA patients matched for demographics, prehospital and emergency department vital signs, mechanism of injury, degree of pelvic disruption in pelvic fracture patients, solid organ injuries, and lower extremity fractures and vascular injuries. The studied outcomes were complications and mortality.

Here are the factoids:

  • Nearly 600,000 records were scanned for the two year period, and only 140 REBOA patients were identified (!)
  • These 140 REBOA patients were matched with 280 similar non-REBOA patients
  • Average age was 44 and average ISS was 29, 74% were males and 92% were blunt trauma
  • Overall complication rate was 7.4% and mortality was 25%
  • There was no difference in 4-hour or 24-hour numbers of blood, plasma, or platelets transfused
  • ICU and hospital length of stay were identical
  • 24-hour mortality in the REBOA group was significantly higher (36% vs 19%)
  • REBOA patients were significantly more likely to require amputation (5% vs 1%)

Bottom line: These are not great numbers for REBOA! What gives? There are a number of possibilities:

  • It’s a database study, so some key information might be missing
  • The numbers remain small, only 140 patients out of half a million records in two years!
  • There is no way to know how the patients were selected for REBOA
  • The experience and skill level at the hospital performing the procedure is not known
  • The interplay of other injuries and comorbidities is unclear
  • And many more…

BUT, the numbers are concerning. The early adopter centers have better outcomes, and this has prompted many centers with fewer eligible patients to jump on the bandwagon. We all need to remember that this is a brand new procedure and we are still learning the nuances. It is extremely important that every center performing REBOA contribute their results to a national registry. We still need to figure out which patients will benefit from it, how it should be used, and how we can minimize complications and maximize survival in our patients.

Reference: Nationwide analysis of resuscitative endovascular balloon occlusion of the aorta (REBOA) in civilian trauma. Session I Paper 5, AAST 2018.

Best of AAST #6: Antibiotics For Chest Tubes??

For as long as I can remember (nearly 50 years worth of literature) there has been some debate about giving antibiotics after chest tube insertion to decrease the infection rate. The pendulum moved back and forth for decades, never getting very far into the “give antibiotics” side. It’s been quite a while since I remember any new papers on this, and I thought the debate had been resolved in favor of never using them.

But then I see an abstract from the AAST multi-institutional trials group studying presumptive antibiotics after chest tube insertion! They conducted a prospective, observational study at 22 Level I trauma centers, enrolling nearly 2,000 patients. They matched patients in antibiotic and no antibiotic groups, arriving at (only) 272 patients in each group.

Here are the results:

Bottom line: First, it’s a little disappointing that the numbers were so low with a trial that includes 22 trauma centers. Did they have a hard time finding centers that would give antibiotics? Or was it just hard to match patients for the variables they were looking at? Regardless, there were no significant differences in infectious complications, and a non-clinically significant difference in ICU stay with antibiotics.

Why won’t this die? If there are so few papers that show an actual benefit from giving antibiotics after chest tube insertion with 50 years of data, then it’s very unlikely that it will ever be shown to be necessary!

Reference: Presumptive antibiotics for tube thoracostomy for traumatic pneumothorax. Session XXII Paper 49, AAST 2018.

Best of AAST #5: Pneumothorax – How Big Is Too Big?

Deciding when to place a chest tube can be challenging. Sometimes, it’s obvious: there is a large hemo- or pneumothorax staring you in the face on the chest x-ray. But sometimes, it’s there but “not that big.” The real question is, how big is too big.

That’s a question that’s been very difficult to quantify. The authors of this abstract, from the Medical College of Wisconsin, conducted a six-year retrospective review of every patient with an isolated pneumothorax at their Level I trauma center. Based on their previous research, a 35mm threshold was used to stratify patients into two groups. This measurement was obtained from axial images of a CT scan. Statistical analysis was performed to identify the predictive value in determining whether the patient could be managed without a chest tube.

Here are the factoids:

  • A total of 1767 patients had a pneumothorax during the 6-year period, and about half met inclusion criteria for the study
  • Of the 385 with pneumothorax alone, 92% were managed without a chest tube
  • Of those 353, 95% had a maximum chest wall to lung distance (335)
  • The 35mm measurement was statistically shown to be an independent predictor of successful management without a tube for both blunt and penetrating trauma

Bottom line: Not so fast! Although this looks like a slam dunk abstract, it’s really not. First, many (or most?) pneumothoraces are initially diagnosed using a plain old chest x-ray. A 35mm measurement is meaningless here because there can be significant changes in position of the pneumothorax on the image. Sometimes, the air is located anteriorly with little or no lateral component.  Does this mean we should CT every patient with a known or suspected pneumothorax? I think not.

And the second issue is the subjectivity surrounding the definition of a failure. What criteria were used when the tube was actually placed in this series. If every patient had to become symptomatic first, then I might agree. But I suspect the tubes were placed when followup imaging showed that the air was just “too big.” You can’t statistic away this kind of potential bias from subjectivity.

So what’s the answer? Unfortunately, there still isn’t one. The need for a chest tube must still be based on subjective size on a chest x-ray, physiologic status, and the patient’s ability to tolerate a given amount of lost lung function. It continues to boil down to the  assessments of each trauma professional as to “how big is too big.”

Reference: Observing pneumothoraces: the 35mm rule is safe for both blunt and penetrating chest trauma. Session XVA Paper 28, AAST 2018.