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Resuscitation

Best Of EAST 2023 #3: The Cost Of Whole Blood vs Component Therapy

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Decades ago, blood banks discovered they could fractionate units of whole blood into components for focused use. This was useful for patients who were thrombocytopenic or needed specific plasma factors. But trauma patients bleed whole blood, and trying to reassemble whole blood from components does not work well. Have a look at this chart:

It all comes down to money. Blood banks found they could charge more for the sum of the components of a unit of whole blood rather than the one unit itself. But now, with whole blood in trauma becoming a thing again, it’s essential to reexamine costs.

The University of Texas at San Antonio group examined transfusion-related charges for trauma patients receiving either component therapy or low-titer O+ whole blood within six hours of arrival. This was a retrospective review of prospectively collected data. During the first two years, only component therapy was given. Whole blood was introduced during the last four years.

Here are the factoids:

  • Once the trauma center switched to whole blood, total annual transfusion charges, as well as component charges decreased by 17% overall
  • In both adults and children, whole blood was associated with a significantly lower cost per ml delivered and cost per patient throughout all phases of care
  • In severely injured patients (ISS>15), the same significantly lower costs were also noted
  • Patients who triggered the massive transfusion protocol also had a lower cost per ml of product in the ED and the first 24 hours

The authors concluded that whole blood was associated with lower charges and “improved logistics,” especially in massive transfusion patients.

Bottom line: This is an interesting and important paper. However, several questions still need to be answered. I recognize that there is limited space in an abstract, so I will list them below in hopes the authors will answer them during the presentation.

The first issue is that the numbers of patients and quantities of blood products given need to be listed. These are very important because the figures list only total charges and maybe costs. These numbers are not per unit of product, so the data may be skewed if the number of patients was different between the groups. For example, if 100 patients received component therapy and only 10 got whole blood, costs or charges could definitely be skewed.

And then there is the cost vs. charge confusion. The abstract seems to use them interchangeably. The methods section of the abstract states that charges were analyzed. Yet cost is mentioned in the results, and figure two shows “cost” on the axes, but the caption states that charges were listed. 

We all know that hospitals can charge whatever they like, and that amount may vary based on insurance and other factors. The relationship between the charge and the cost is tenuous at best. Hopefully, the authors will clarify this at the start of the presentation.

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

  • Please clarify the concept of charges vs. costs at the presentation’s beginning. If you truly analyzed only charges, do they bear any relationship to the actual costs of the units?
  • Shouldn’t your analysis of annual “charges” for product expenditures in Figure 1 be per unit? Otherwise, the costs and charges could be lower if fewer products were given after whole blood was introduced.
  • Was the switch to whole blood absolute, or was component therapy still given in some cases after 2018? If the switch was not total, there could be a selection bias in patients who received whole blood.
  • Figure 2 also appears to be total charges (or costs), not per patient or unit. But, again, without numbers it is difficult to say if the dollar differences are significant.
  • What are the “improved logistics” mentioned in the conclusion section? And how could they lower charges (or costs) in your study?

Lots of questions. I think you will need to provide a lot of explanation up front to justify your findings. Nevertheless, I’m excited about the presentation.

Reference: TRANSFUSION-RELATED COST COMPARISON OF TRAUMA PATIENTS RECEIVING WHOLE BLOOD VERSUS COMPONENT THERAPY. EAST 2023 podium abstract #28.

Abstracts, Resuscitation

Best of EAST 2023 #2: REBOA In Cardiac Arrest

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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.

Reference: REBOA AND RESUSCITATIVE THORACOTOMY ARE ASSOCIATED WITH SIMILAR OUTCOMES AFTER TRAUMATIC CARDIAC ARREST. EAST 2023 podium abstract #11.

 

Research

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

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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.

Abstracts

Coming Up: EAST Scientific Abstract Presentations

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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:

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.