All posts by TheTraumaPro

Best Of EAST 2023 #1: The Quality Of Trauma Research

I’ve been reading and reviewing scientific papers for years. One of my biggest pet peeves is the preponderance of studies that have been thrown together with insufficient thought given to research design. One of the most common issues I see in any study is the failure to look at study size and statistical power. The biggest offenders are the underpowered non-inferiority studies that claim two choices are equally valid when there were never enough subjects to show a difference in the first place!

If you want to see this in action, look at the studies that justify the “small chest tube is not inferior to bigger chest tube” studies.

But I digress. The first EAST abstract, I will discuss critically examined randomized clinical trials (RCT) relating to trauma published over ten years. The authors, from the Ryder Trauma Center in Miami, reviewed these studies for type (superiority, inferiority, equivalence), sample size calculation, and power analysis.

Here are the factoids:

  • Only 118 randomized clinical trials were identified in 20 journals over the ten years (!!)
  • Only half were registered before performing the research
  • Most were equivalence studies (49%)
  • Only half had performed a sample size calculation first, and only half of those actually met their target enrollment (!)
  • 70% of studies had a positive result
  • Overall, only about one-third to one-half of studies were adequately powered to show an effect size

The authors concluded that a large number of RCTs either did not perform a sample size calculation in advance, did not meet their enrollment targets, and weren’t powered enough to detect even a large effect.

Bottom line: Unfortunately, this abstract confirms my informal bias based on reading numerous papers over the years. There is a lot of weak research being published. And this applies not only to the field of trauma but to all scientific work.

There is a tremendous amount of pressure to publish. Those at academic institutions must be productive to keep their job. And the American College of Surgeons Verification Review Committee requires Level I trauma centers to publish twenty papers in peer-reviewed journals every three years. 

Unfortunately, this pressure pushes trauma professionals to come up with weak ideas that may not be well supported statistically. And there is an implicit bias in research publications that rewards positive results. This can be seen in this abstract’s 70% positive result rate. It’s boring to read a paper that shows that some new approach truly didn’t have an appreciable effect. But knowing this fact may help other researchers in the field avoid duplicating ineffective interventions.

This is an important abstract that clearly points out the shortcomings in published randomized controlled trials. But what about the 95+ percent of papers that do not use such a rigorous study design?

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

  • Please provide the denominator of all the studies you reviewed. Only 118 were RCTs, which is woefully low. Please give us an idea of how many less rigorous studies were published over the ten-year study period.
  • Were there any obvious geographical patterns in study quality? Were RCTs from any specific continent of higher quality from the sample size perspective than others?

This important abstract is needed to stimulate more thought and interest in publishing better papers rather than more papers!

Reference: STATISTICAL POWER OF RANDOMIZED CONTROLLED TRIALS (RCT) IN THE FIELD OF TRAUMA SURGERY. EAST 2023 podium abstract #6.

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
  • REBOA
  • 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:

Scoop And Run VS Stay And Play: Part 5

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.

Scoop And Run VS Stay And Play: Part 4

I’ve been discussing the little research there is on stay and play vs scoop and run. And now, hot off the press, we have a paper about the ultimate version of scoop and run, the “drive-by ambulance.” This one looks at outcomes in patients who are dropped at the emergency department by private vehicle. This is the most basic form of prehospital care, with no interventions, just transportation. This type of transport is used by parents with their injured children, police who act as very basic first responders in some cities, and on occasion, gang members.

A multi-institutional group of authors used data in the National Trauma Databank to try to answer this question. They used three years worth of data, comparing outcomes from patients with ground EMS vs private transport who were treated at Level I and Level II trauma centers. Only gunshots and stabs were included, and all patients were 16 or older.  The  authors were focused on only one thing: mortality. This included death in the ED, and a model was developed to adjust risk based on vital signs, injury severity score (ISS), race, and insurance status. Just over 100,000 were included in he final analysis.

Here are the factoids:

  • Black and hispanic patients were more frequently transported by private vehicle, but only by about 3%
  • White patients were more frequently taken by ground EMS, by about 6%
  • Stabs were more likely to be brought by private car than gunshots, 56% vs 44%
  • Mean ISS was significantly higher for those transported by ground EMS (10 vs 5.5)
  • Unadjusted mortality was lower overall for private vehicle, 2% vs 12%
  • The chance of dying in the ED was also decreased in the private transport patients, from 7% to 1%
  • Mortality from both gunshots and stabs were also significantly lower (5% vs 9%, and 0.2% vs 3% respectively)
  • Once adjusted for risk, the lower mortality with private transport remained, with a 60% risk reduction of death. This persisted in the gunshot and stab cohorts as well.

Bottom line: Wow! Although this study has the usual limitations of using a large external database, it was very well designed to compensate for that. And the degree of improvement in survival is surprising. What this study can’t tell us is why. Certainly, some patients benefit from a little extra time to give fluid or blood, intubate, or provide some other treatments. But the patient with penetrating injuries frequently do not need this, they just need definitive control of hemorrhage. The authors even go so far as to suggest that at-risk populations receive education on “scoop and run” if people they know suffer penetrating injury.

The next step is to tease out which components of the stay and play paradigm are the most valuable, and which contribute to the increased mortality in penetrating injury patients.

In my final post on the series, I will discuss a new multi-center trial from EAST that concentrates on penetrating injury.

Reference: Association of Prehospital Mode of Transport With Mortality in Penetrating Trauma A Trauma System–Level Assessment of Private Vehicle Transportation vs Ground Emergency Medical Services. JAMA Surgery, Published online September 20, 2017.

Scoop And Run VS Stay And Play: Part 3

Scoop and run or stay and play. Is one better that the other? Over my last two posts, I reviewed a couple of papers that were older (6-7 years) and had smaller patient groups. Now let’s look at a more recent one with a larger experience using a state trauma registry.

This one is from the Universities of Pittsburgh and Rochester, and used the Pennsylvania state trauma registry for study material. The authors wanted to really slice and dice the data, postulating that previous studies were not granular enough, such that significant trends could not be seen due to lumping all prehospital time together. They divided prehospital time into three components: response time, scene time, and transport time. To some degree, the first and third components are outside of the prehospital providers’ control.

The records for over 164,000 patients were analyzed. These only included those for patients transported from the scene by EMS, and excluded burns. The prehospital time (PH time) was divided into the three components above. A component was determined to be prolonged if it contributed > 50% of the total PH time.

Here are the factoids:

  • Half of the patients had a prolonged PH time interval (52%)
  • Response time was prolonged in only 2%, scene time was prolonged in 19%, and transport time was longer in 31%
  • Mortality was 21% higher in those with a prolonged scene time component
  • There was no mortality difference in patients with no prolonged time components, or those with prolonged response or transport times
  • These patterns held for both blunt and penetrating injury
  • Extrication and intubation were common reasons for prolonged scene time. Extrication added an average of 4.5 minutes, and intubation 6.5 minutes.
  • Mortality was increased with prehospital intubation, but this effect lessened in severe TBI
  • Increasing experience with extrication and intubation appeared to decrease the mortality from the increased scene time they caused

Bottom line: This paper suggests that the dichotomy of “scoop and run” vs “stay and play” may be too crude, and that a more nuanced approach should be considered. In plain English, the optimal management lies somewhere in between these polar opposites. Actual on scene time appears to be the key interval. EMS providers need to be aware of scene time relative to response and transport times. Patients with specific injury patterns that benefit from short scene times (hypotension, flail, penetrating injury) can quickly be identified and care expedited. Increased scene time due extrication cannot be avoided, but prehospital intubation needs to be considered carefully due to the potential to increase mortality in select patients. 

Reference: Not all prehospital time is equal: Influence of scene time on mortality. J Trauma 81(1):93-100, 2016.