Category Archives: Abstracts

Best Of EAST 2023 #5: Imaging The Elderly

Several papers have been published over the years regarding underdiagnosis when applying the usual imaging guidelines to elderly trauma patients. Unfortunately, our elders are more fragile than the younger patients those guidelines were based on, leading to injury from lesser mechanisms. They also do not experience pain the same way and may sustain serious injuries that produce no discomfort on physical exam. Yet many trauma professionals continue to apply standard imaging guidelines that may not apply to older patients.

EAST sponsored a multicenter trial on the use of CT scans to minimize missed injuries. Eighteen Level I and Level II trauma centers prospectively enrolled elderly (age 65+) trauma patients in the study over one year. Besides the usual demographic information, data on physical exams, imaging studies, and injuries identified were also collected. The study sought to determine the incidence of delayed injury diagnosis, defined as any identified injury that was not initially imaged with a CT scan.

Here are the factoids:

  • Over 5,000 patients were enrolled, with a median age of 79
  • Falls were common, with 65% of patients presenting after one
  • Nearly 80% of patients actually sustained an injury (!)
  • Head and cervical spine were imaged in about 90% of patients, making them the most common initial studies
  • The most commonly missed injuries involved BCVI (blunt carotid and vertebral injury) or thoracic/lumbar spine fractures
  • 38% of BCVI injuries and 60% of T/L spine fractures were not identified during initial imaging
  • Patients who were transferred in, did not speak English, or suffered from dementia were significantly more likely to experience delayed diagnosis

The authors concluded that about one in ten elderly blunt trauma patients sustained injuries in body regions not imaged initially. They recommended the use of imaging guidelines to minimize this risk.

Bottom line: Finally! It has taken this long to perform a study that promotes standardizing how we perform initial patient imaging after blunt trauma. Granted, this study only applies to older patients, but the concept can also be used for younger ones. The elderly version must mandate certain studies, such as head and the entire spine. Physical exams can  still be incorporated in the guidelines for younger patients but not the elderly.

The overall incidence of BCVI was low, only 0.7%. But its presence was missed in 38% of patients, setting them up for a potential  stroke. Some way to incorporate CT angiography of the neck will need to be developed. The risk / benefit ratio of the contrast load vs. stroke risk will also have to be determined.

Here are my questions and comments for the presenter/authors:

  • Did you capture all of the geriatric patients presenting to the study hospitals? By my calculation, 5468 patients divided by 18 trauma centers divided by 14 months of study equals 22 patients enrolled per center per month. Hmm, my center sees more than that number of elderly injured patients in the ED per day! Why are there so few patients in your study? Were there some selection criteria not mentioned in the abstract?
  • Why should we believe these study numbers if you only included a subset of the total patients that were imaged?

My own reading of the literature leads me to believe that your conclusions are correct. I believe that all centers should develop or revise their elderly imaging guidelines to include certain mandatory scans regardless of how benign the physical exam appears. Our elders don’t manifest symptoms as reliably as the young. But the audience needs a little more information to help them understand some of the study numbers.


Print Friendly, PDF & Email

Best of EAST 2023 #2: REBOA In Cardiac Arrest

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) remains one of the shiny new trauma toys. Yet, with nearly a decade of human study, we are still struggling to define the right patients to benefit from it.

A group of REBOA superfans sought to perform a secondary analysis of a research database from the US Department of Defense of patients at six Level I centers in the US. It contained outcomes of patients in hemorrhagic shock due to non-compressible bleeding below the diaphragm. The authors analyzed the subset of patients who presented in cardiac arrest and underwent either REBOA or resuscitative thoracotomy (RT).

Here are the factoids:

  • There were 454 patients in the database, and 72 underwent either REBOA or RT
  • REBOA patients were significantly older (46 vs. 35 years) and were more commonly victims of blunt injury (81% vs. 46%)
  • AIS for abdomen was lower in the REBOA group, but AIS head and chest were the same
  • Times from arrival to aortic occlusion and to procedure completion were significantly longer in the REBOA group
  • REBOA patients received more red cells and plasma in the ED, but 24-hour transfusions were the same
  • Mortality was the same between REBOA and RT, and did not change even after some statistical magic

The authors concluded that REBOA was not associated with a survival or transfusion advantage in patients already in arrest.

Bottom line: I was amazed to see a negative result from a group who tend to be avid REBOA cheerleaders. And although the abstract conforms to my own bias about REBOA, there are several things to consider here. 

First, the sample size is very small. A total of 72 patients from the database fit the cardiac arrest on arrival criterion. There is also no information on prehospital arrest duration for the patients.  The dead tend to stay dead despite just about any intervention.

Here are my questions for the presenter and authors:

  • Have you performed a power analysis to determine how many patients were needed to show real differences between the groups? Were you getting close with the 72, or a lot more needed?
  • Also, you did not break down how many of the 72 patients were in the REBOA vs RT groups. Please provide those numbers.
  • Were you able to determine how long the patients had been in arrest before arrival? This could definitely influence survival rates.
  • Did you analyze the subset of survivors in each group? You noted that times to procedure start and completion were longer with REBOA. Did the survivors get to aortic occlusion sooner? Could you identify any subjective factors that seemed associated with their survival?

I wouldn’t get too depressed yet about the efficacy of REBOA in these patients. This study just tells us that REBOA is not a miracle cure for cardiac arrest, but we can still continue to learn more about this device and which patients it is best suited for.



Print Friendly, PDF & Email

Coming Up: EAST Scientific Abstract Presentations

It’s that time of year again! The Eastern Association for the Surgery of Trauma (EAST) Annual Scientific Assembly is just around the corner. And as usual, I have selected a number of the more interesting and intriguing abstracts to analyze here.

I will look at the idea behind each abstract, analyze the research work that went into it, give you my take as to the validity and significance, and provide some comments to the presenter and authors to help prepare them for questions during their presentation.

Here are some of the interesting topics I will be covering:

  • A hard look at trauma research quality
  • Early VTE prophylaxis in severe TBI
  • Whole blood for TBI and shock
  • Cost of whole blood use
  • Trauma imaging in the elderly
  • Where should trauma patients be intubated?
  • Post-mortem CT scanning
  • Detecting rib fractures with AI
  • Timing of rib fracture analgesia
  • CT imaging of the spine
  • Elderly falls prevention
  • VTE prophylaxis in adolescents
  • TXA
  • Completion angiography
  • Damage control skin closure

Generally, I do not discuss animal, basic science, biomarker or other research that does not have the potential for obvious and immediate impact on clinical trauma care. Occasionally I will make an exception if findings are novel and/or exciting enough to signal the arrival of a new area of research.

We will see if I can get to all of these intriguing abstracts starting next Monday. And if any of my readers have a specific abstract in mind for me to discuss, please email or leave a comment below.

Here are links to the abstracts direct from the EAST website:

Print Friendly, PDF & Email

Best Of AAST 2022 #12: Angioembolization For Liver Injuries

Solid organ injuries are relatively common from both blunt and penetrating mechanism due to the fact that the liver is the largest organ in the torso. Management of minor injury is relatively straightforward, but more complex injuries quickly become complicated. Unlike the spleen, there is no option to just “drop it in the bucket.” And recovery from high-grade hepatic injuries is fraught with issues like bleeding and bile leaks. These patients may take weeks or months to fully recover.

A wide variety of operative techniques for controlling liver bleeding were developed in the 1900s. These became a little less relevant late in the century with the addition of angiography and embolization to our suite of management techniques. Remember, angioembolization does not replace operative management, which is mandatory in unstable patients. But it can certainly help control bleeding and may reduce the need to operate early.

The group at Johns Hopkins hypothesized that angioembolization (AE) improves survival in patients with severe hepatic injuries. They collected data from 29 trauma centers in an AAST multicenter study. It focused on adult patients with Grade III-V injury from either blunt or penetrating mechanism. The data were sliced and diced by mechanism and type of management. There were three management possibilities: nonop management with or without AE, operative management with AE before or after, and operative management alone.

Here are the factoids:

  • A total of 1,697 blunt and 733 penetrating liver injury patients were studied with similar median ISS
  • As expected, higher ISS and blood transfusion > 6u was significantly associated with higher mortality
  • In the blunt injured patients managed nonoperatively, there was no association between mortality and use of AE although the p value was 0.056
  • Similarly, blunt trauma patients who underwent an operation and had AE either before or after had no difference in mortality (p value 0.09)
  • There was a significant survival advantage if AE was added to nonoperative management

The authors concluded that angioembolization does not improve survival in most severe liver injury cases with the exception of high-grade penetrating injury.

Bottom line: This abstract focuses on survival advantage from the use of AE. However, I think most trauma professionals actually use it as an adjunct to make other management (operative or nonoperative) easier. So I’m not surprised that they didn’t find much positive to say except in the case of penetrating injuries.

I also worry that the p values for both groups of blunt patients (operative + AE, nonop + AE) were very close to significance. Any time a study provides a negative conclusion because significance was not reached, I want to be sure it had the statistical power to detect it in the first place. With p values of 0.09 and 0.056, could a few more patients in each group have achieved statistical significance?

I don’t see that this abstract could (or even should) change our practice in the use of AE. I suspect that it does have an impact on complications, and it may help us stay out of the abdomen in severe cases where opening it could result in uncontrollable bleeding.

Here are my questions and comments for the authors / presenter:

  1. Did you do a power analysis to determine if you could actually show a significant difference in the blunt patients? Although you had 1,697 total blunt patients, we do not know how many were in the operative vs nonop groups and the AE vs no AE subset of the nonop management group.
  2. Were there any differences in the ISS, age, or other demographics in the pre vs post or AE/no AE blunt subsets that might reveal some selection bias for patients undergoing in one subset vs the other? Since this is pooled data from many trauma centers, each surgeon determines if AE is used and when. It becomes very important to try to identify other factors that may explain your results.
  3. Do you recommend any changes in clinical care based on these results? What needs to be done to definitively answer the question?

This is interesting preliminary work, but I believe it needs additional refinement before we learn enough to change our current practice.


Print Friendly, PDF & Email

Best Of AAST 2022 #11: Trauma And The Gut Microbiome

You know I don’t usually write about animal studies. I’m going to break that rule today to review an abstract that addresses what I think is an under-appreciated contributor to outcomes in trauma. The gut microbiome describes the collection of all genomes from microorganisms found in a particular environment. These genomes include bacteria, viruses, and fungi and can be found on all external surfaces of humans.

And I use the term “external” loosely. It includes the areas of the human body that are obviously exposed to the environment, but also areas where our body is wrapped around yet still separate from the it, such as the aerodigestive tract and vagina.

We are beginning to recognize the importance of the micro-organisms that inhabit these areas. They aid in digestion, fine tune the immune system, and synthesize proteins, amino acids, and vitamins that are essential to our health to name a few key tasks.

Many things can disrupt the microbiome including disease, diet, stress, and antibiotics. Previous work has shown that the microbiome changes throughout the hospital stay after trauma. Beneficial species tend to die out, and the ratio of pathologic vs beneficial species tilts toward the dark side.

The group from the University of Florida studied the effects of trauma and chronic stress in a group of rats to study the impact on the gut microbiome. One group of rats was subjected to a polytrauma model including pulmonary contusion, shock, cecectomy, and femur fractures. Another received the polytrauma treatment plus two hours of restraint stress daily. These groups were compared to an untreated control group. Gut flora were measured at baseline and on days 3 and 7.

Here are the factoids:

  • As expected, the microbiomes were similar across all groups at baseline
  • Polytrauma caused a significant change in bacterial diversity at both days 3 and 7 with both Bacteroides and Enterococcus prevalent
  • Polytrauma plus stress also depleted “good bacteria” and was associated with a switch to predominantly Enterococcus colonization

The authors suggested that the observed transitions to a pathologic microbiome may influence outcomes after severe trauma and critical illness.

Bottom line: I wanted to highlight this simple study because it relates to a similar topic that is exploding in the clinical nutrition field. The gut microbiome is being recognized as a key element of our overall health. However, it is very sensitive to external events and can be “knocked out of whack” by stress, trauma, bad diet, and even a single dose of antibiotics. Its derangement is recognized as a major factor in the development of C Difficile colitis.

This simple little rat study confirms that major trauma and stress negatively impact the animals’ microbiome. It did not examine outcomes, so no associations can be made here. Any such associations would not be directly applicable to humans, anyway. But it should serve to stimulate some thought and additional human studies to continue investigation in this field.

I have been struck by how we mistreat the gut microbiome in hospitalized patients through my own clinical observations over the years. A short course of antibiotics has been shown to severely impact the diversity of gut flora within days, and may require a year or more to recover back to baseline.

Extended fasting exhausts the food supply for the bacteria which may lead to the use of the gut lining for food, creating additional pathology. The composition of the nutritional supplements used in hospital are formulated from cheap ingredients which have been shown to disrupt the microbiome. Then add on trauma and chronic stress. It’s a terrible combination, yet we see it every day in hospitalized patients!

I predict that we will learn to pay more attention to all our various microbiomes in the future. A more thorough understanding may allow us to reduce complications (think C Diff) and might help us recognize some subtle factors that are contributing to overall mortality. 

Here are my comments and questions for the authors / presenters:

  1. The audience will not be familiar with the microbiome diversity measures described in the abstract. Please take a little time to explain it, what is normal, and what happens when it changes.
  2. Were there any obvious outcome correlations observed that were not reported?
  3. Where do you go from here? Any plans for human studies on this topic?

As you can see, I find this area fascinating and believe that it is an underappreciated source of outcome variability in the patients we take care of. Figuring this out will help us tweak and optimize our overall patient care.


Print Friendly, PDF & Email