Category Archives: Complications

Complications, Prehospital

Scoop And Run VS Stay And Play: Part 5

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This is the last piece in my series on whether or not trauma patients should be initially managed with some limited interventions at the scene, vs just getting them into the ambulance and on their way to a trauma center. This article deals specifically with the needs of victims of penetrating trauma in big cities.

The Eastern Association for the Surgery of Trauma (EAST) published the results of a multicenter trial on the utility of prehospital procedures performed by EMTs and medics in this subset of patients. Most of the studies previously reviewed do not show an obvious advantage to dawdling at the scene.

The EAST study took an interesting approach. It limited patients to those in urban locations near trauma centers, which largely eliminated time from the equation. The authors could then attempt to identify any utility in performing procedures prior to trauma center arrival.

This was an observational trial of adults with penetrating injury to the torso or proximal extremity. A total of 25 trauma centers participated for a one-year period. Patients with penetrating injuries above the clavicles or in the distal extremities were excluded.

Here are the factoids:

  • Although 2,352 patients met inclusion criteria, a small number (68) were excluded because the method of transport was missing (!)
  • Type of transport was ALS (63%), private vehicle (17%), police (14%), and BLS (7%)
  • Nearly two-thirds (61%) received some type of prehospital procedure
  • The procedures performed included intubation (6% on scene, 2% in transport), IV access (49% on scene, 42% in transport), IO access (5% on scene, 3% in transport), fluid resuscitation (16% on scene, 32% in transport),application of a pressure dressing (23% on scene, 12% in transport), and tourniquet application (6% on scene, 2% in transport)
  • Patients who received prehospital interventions had significantly longer hospital length of stay (5.6 vs 4 days) and were more likely to develop ARDS, venous thromboembolisms, and urinary tract infections
  • In-hospital mortality was significantly higher in the intervention group (10.3% vs 7.8%)
  • Mortality significantly increased with the number of interventions performed at the scene and enroute to the trauma center
  • Prehospital intubation was strongly correlated with mortality, and the following procedures were also associated with higher mortality: fluid resuscitation, cervical spine immobilization, and pleural decompression
  • Prehospital IV insertion was significantly associated with survival, but tourniquet placement was neutral
  • There was no mortality difference based on the type of transport provided

Bottom line: This is a fascinating paper that applies to a limited subset of patients. Specifically, it only studied patients in urban areas with a trauma center that was presumably very close. Prehospital endotracheal intubation proved to be the most deadly intervention. A few studies have confirmed that intubation further degrades end-organ perfusion further in animals with severe hemorrhagic shock.

The finding that prehospital fluids were associated with higher mortality, but that IV access was not, is puzzling at first. However, there are a number of papers clearly showing that resuscitation without definitive hemorrhage control, can be deadly. This study confirms this fact in humans and lends support to the concept of permissive hypotension in these patients. 

Cervical spine immobilization proved to be a mortality risk. The reasons are not clear, but difficulties in placing an airway and increased intracranial pressure could be factors. The only clear indication would be for stabilization of the neck in patients with cervical cord injuries. However, in such cases the damage is done and collars are likely not of any benefit neurologically.

The biggest flaw in this study was that it did not record transport times. The authors assumed that times were short since the patients were injured in high density urban areas. There was also concern for selection bias, as more severely injured patients were more likely to undergo prehospital intervention.

The takeaway message is that in a setting with very short transport time to a trauma center, hemorrhage control trumps almost everything else. Obtaining IV access or applying a tourniquet may be beneficial, but should only occur once the patient is enroute to minimize time on scene. More advanced maneuvers such as fluid resuscitation, fluid resuscitation, collar placement, or needle decompression of the chest should be delayed for management by the trauma team.

These results cannot be generalized to patients with longer expected transport times, although we don’t have good research yet to back up this assertion. In those patients, it is probably best to adhere to the good old ABCs of ATLS. And of course, until this work is confirmed by more studies, do not go against any policies or procedures established by your prehospital agency!

Reference: An Eastern Association for the Surgery of Trauma multicenter trial examining prehospital procedures in penetrating trauma patients. J Trauma 91(1):130-140, 2021.

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Complications

TXA Hesitancy: Part II

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In my last post, I reviewed a huge systematic review and meta-analysis of the use of tranexamic acid (TXA)  by all medical disciplines using it. There were more than 125,000 cases included and showed the incidence of thrombotic complications in TXA vs non-TXA patients was exactly the same at about 2%.

Our orthopedic surgery colleagues have been using TXA to reduce bleeding in their cases for decades. There is nothing close to the degree of “TXA hesitancy” in orthopedic surgeons than I see in surgical practices across trauma centers. What do the orthopods know that we don’t?

Trauma orthopedic groups in Malta and the UK published a paper just this month in which they performed a systematic review and meta-analysis of the use of TXA in hip fracture surgery. They focused on randomized, controlled trials published after 2010. A standard approach was used in the analysis, which looked specifically at the impact of IV TXA on transfusion requirements in surgery. Only adults were studied, and eligible studies compared TXA with a placebo, or TXA with no TXA.

Here are the factoids:

  • Out of 85 studies initially identified, only 13 met all criteria
  • Across these trials, a total of 1194 patients were enrolled
  • The need for blood transfusion was reduced by more than 50% when the transfusion threshold was Hgb 8g/dl, which was highly statistically significant
  • When a higher transfusion threshold was used (between 8-10 g/dl Hbg) the risk reduction was only 23% which was not significant
  • The incidence of thrombotic events was identical for TXA and no-TXA groups

Bottom line: This paper presents more high-quality evidence that the use of TXA in surgically induced injury (hip fracture repair) significantly reduces the need for transfusion in the group with the most blood loss. 

However, as with any meta-analysis the results are only as good as the quality of the individual papers. There were differences in how the TXA was given. It was also not possible to separate out results from the various types of hip surgery performed. And obviously, these are not major, multi-trauma patients.

Most TXA hesitant surgeons are either concerned with the efficacy of TXA, or the potential risks. This paper shows that, overall, TXA is effect in these patients despite the mix of doses and timing of delivery. And it clearly shows that the risk for thrombotic complications was identical to that of not giving it.

We have a cheap, effective tool to reduce the need for blood transfusion (read “blood loss”) in trauma patients that has a totally neutral risk profile for thrombosis. We all need to ask ourselves, “why are we not using it?”

Reference: The Use of Tranexamic Acid in Hip Fracture Surgery — A
Systematic Review and Meta-analysis . J Orthop Trauma, 36(2):e442-3448, 2022.

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Complications

TXA Hesitancy: Part I

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I’ve visited several hundred trauma centers over the past 25 years, and recently I’ve begun to appreciate that there are two tribes when it comes to the use of tranexamic acid: the TXA believers and the TXA hesitant.

There have been a number of large studies that seem to suggest a benefit with respect to survival from major hemorrhage, particularly if given soon after injury (CRASH-2, MATTERs). This drug is dirt cheap and has been around a long time, so it has a clearly defined risk profile.

However, many of those hesitant to use it point to the possibility of thromboembolic events that have been sporadically reported. Several years ago, I did my own literature review and found that the number of thrombotic events from TXA was nearly identical to that of transfusing plasma.

JAMA Surgery published a large systematic review, meta-analysis, and meta-regression last year that sought to examine the association between thromboembolic events (TE) in patients of any age and involving all medical disciplines, not just trauma.

The anesthesia group at the University Hospital Frankfurt in German did a systematic search of the Cochrane Central Register of Controlled Trials, as well as MEDLINE, for randomized controlled trials involving TXA. They covered all published studies through December 2020.

The authors adhered to standard guidelines for conducting reviews and meta-analysis (PRISMA). They specifically searched for outcomes involving TEs, such as venous thromboembolism, myocardial infarction or ischemia, limb ischemia, mesenteric thrombosis, and hepatic artery thrombosis. They also tallied the overall mortality, bleeding mortality, and non-bleeding mortality.

Here are the factoids:

  • A total of 216 eligible trials were identified that included over 125,000 patients (!)
  • Total TEs in the TXA group were 1,020 (2.1%) vs 900 (2.0%) in the control group
  • Studies at lowest risk for selection bias showed similar results

Bottom line: The authors concluded that IV TXA, irrespective of the dose, does not increase the risk of thromboembolic events. Period.

In my next post I’ll describe an even more recent systematic review and meta-analysis in orthopedic patients. Our orthopedic colleagues have been using this drug successfully for hip surgery for decades. Let’s see what they think.

Reference: Association of Intravenous Tranexamic Acid With Thromboembolic Events and Mortality A Systematic Review, Meta-analysis, and Meta-regression. JAMA Surgery 156(6):3210884, 2021.

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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.

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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.

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