All posts by The Trauma Pro

Equipment, Prehospital

Cool EMS Stuff: The Backboard Washer!

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Backboards are made to get messy. And every time your friendly EMS provider brings you a patient, they invariably have to swab it down to give the next patient a reasonably sanitary surface to lie on. But sometimes the boards get downright nasty and the cleanup job is a major production.

Enter… the backboard washer. I recently saw one of these for the first time at a Level III hospital in Ohio. Fascinating! Pop the board inside and seven minutes later it’s clean. And I mean really squeaky clean. You may think it looks clean and a good hand wash, but just take a look at the effluent water coming out of this washer!

These units use standard 100V 20A power and only require a hot water hookup and a drain. They can wash two boards at once.

Hospitals in the know need to locate one of these next to a work area for completing paperwork and some free food. What could be better?

Reference: Aqua Phase A-8000 spec sheet. Click to download.

Complications

Complications After Single-Look Laparotomy

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Damage control laparotomy (DCL) has been around now for over 25 years. Many, many papers have been written on its benefits, and the decreased mortality for abdominal trauma specifically. In fact, its use has been generalized to trauma for all other body cavities as well.

However, with this improved mortality came an increase in complications. Incisional hernias remain common, as do episodes of delayed small bowel obstruction. Much of the emphasis in traumatic damage control surgery has now shifted to finding ways to close wounds more quickly and reduce the overall complication rate.

In contrast to damage control laparotomy, much less is known about the potential complications associated with the single-look trauma laparotomy.

This procedure is carried out more frequently than DCL, but we have spent less time studying outcomes and risk factors for complications in this group of patients.

The surgery group at Scripps Mercy Hospital in San Diego conducted a statewide retrospective review of a hospital discharge database of adult trauma patients over an eight-year period. Patients with multiple laparotomies were excluded, as it was assumed that these were damage control patients.

The primary outcomes studied were surgical complications, including bowel obstruction, hernia, fistula, wound infection or dehiscence, and evisceration. Complications were recorded during the initial admission, and during any readmissions in the study period.

Here are the factoids:

  • Over 3700 patients were identified as undergoing trauma laparotomy during the study period
  • About 2100 were left for review after excluding those with multiple laparotomies (DCL) or an unclear trauma mechanism
  • 80% of patients were male and 60% had a penetrating mechanism
  • One third of patients were readmitted for a surgery-related complication: SBO 18%, hernia 12%, infection 9%
  • Median time to readmission was about 4 months (range 1 week to 1.5 years)
  • Patients with blunt injury tended to present with complications earlier (6 days) than penetrating injuries (6 weeks)

Bottom line: This paper is unique in that it is one of the few that was able to follow a large patient population for complications occurring both during and after the initial admission. The overall complication rate was surprisingly high (33%), which is similar to that seen after emergency surgery.

Knowing all of this, what should we do? To date, we have not come close to solving the problems of postop adhesive small bowel obstruction, wound infection, and incisional hernia in any surgical population. However, this work points out the importance of counseling our patients about the potential for complications, how to recognize them, and when to present for evaluation and treatment.

Reference: Outcomes after single-look trauma laparotomy: A large population-based study. J Trauma 86(4):565-572, 2019.

Abdomen

Trauma And The Gut Microbiome

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This is a follow-on post from one published last week (gut microbiome changes in rats due to trauma). Click here to read it.

One of the newest frontiers in health-related research recognizes the importance of the human microbiome. This term describes the collection of all genomes from the microorganisms found in a particular environment, such as in, on, or around a human. The term microbiota refers to the specific bacteria, viruses, and fungi that colonize the areas within this environment.

Within the last decade or so, we have just begun to appreciate the importance of the microorganisms that live within us. From a purely numerical standpoint, there are 10 times as many of them as there are our own human cells. However, since they are so small in comparison, we can’t really appreciate the huge number of “other” cells in and on us.

These tiny cohabitants provide many, many functions that are important to our health and well-being. They protect us from pathogenic organisms, help digest our food, fine-tune our immune system, and synthesize proteins, amino acids, and vitamins that are essential to our health. And much more!

The usual microbiota can be disrupted by disease, poor diet, stress, and even a single dose of antibiotics. With each new research paper, we recognize new functions for and disruptors of our microbiota.

The surgery groups at two San Antonio hospitals, UT Health and the US Army Institute of Surgical Research, recognize the importance of the gut microbiota, building upon prior work demonstrating changes within it in the presence of trauma and burn injury.

The authors performed a prospective, observational cohort study of severely injured patients over a two-year period. They attempted to characterize differences in the microbiota between trauma patients and to identify changes in these communities over time.

A rectal swab was obtained from each patient shortly after admission and the microbial DNA present was identified. This was repeated regularly throughout the hospital stay.

Here are the factoids:

  • 72 patients and 13 healthy controls were enrolled
  • Patients were severely injured with a mean ISS of 21; an average of 6 units of blood products were given in the first 24 hours
  • Only one fourth of the injured patients had a microbiome similar to the healthy controls
  • These 26% received significantly more blood products than the dissimilar patients (14 units vs 3)
  • There were significant decreases in the numbers and ratios of normal gut bacteria and increases in the numbers of pathogenic bacteria. These changes increased with time in hospital

Bottom line: Yes, this is new and bizarre territory. It appears that shock, hypoxia, medications (and not just antibiotics), surgical intervention, and poor nutrition can adversely affect the microflora in our gut. Conversely, early transfusion seems to ameliorate this effect to some degree.

At this point in time, there is nothing you can do with this knowledge. Just be aware that everything you routinely do to your patients can change their microbiota, and this may in turn have unexpected effects on their health and recovery. I anticipate seeing many more papers like this one in the near future.

Reference: A prospective study in severely injured patients reveals an altered gut microbiome is associated with transfusion volume. J Trauma 86(4):573-582, 2019.

Abstracts, Outcomes

Best Of AAST 2022 #12: Angioembolization For Liver Injuries

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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.

Reference: AAST MULTICENTER STUDY: DOES ANGIOEMBOLIZATION IMPROVE SURVIVAL FOR SEVERE HEPATIC INJURIES? AAST plenary paer #51, AAST 2022.

Abstracts, Complications

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

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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.

Reference: MULTICOMPARTMENTAL TRAUMATIC INJURY AND THE MICROBIOME: SHIFT TO A PATHOBIOME. Plenary paper #54, AAST 2022.