Tag Archives: abstracts

Abstracts

Best Of EAST #5: How Good Is Lung Ultrasound For Pneumothorax?

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Focused abdominal sonography for trauma (FAST) has been a mainstay of rapid diagnosis for many years. The extended FAST exam (eFAST) adds an examination of the thoracic cavities to the basic exam. The sensitivity and specificity of FAST have mostly been determined. However, there is much less literature outlining the accuracy of the eFAST.

The group at Vanderbilt performed a prospective, observational study on the ability of the eFAST exam to detect pneumothorax specifically.  Imaging was performed by a licensed sonographer and read by the attending surgeon and a radiologist as it was completed.

Here are the factoids:

  • Only patients receiving chest X-rays, chest ultrasound, and chest CT for confirmation were included in the study, which totaled 1,499
  • The statistical analysis was as follows:
  • Only 25% of patients had a chest tube placed
  • Patients with false negative exams were more likely to have rib fractures and lower oxygen saturation and blood pressure

The authors concluded that chest ultrasound had a low sensitivity and high false negative rate and that many of the negatives eventually required chest tube insertion. They advise that the chest ultrasound should be used alone with caution.

Bottom line: This is an interesting and relatively large study. However, it is at odds with a paper published in 2021 from George Washington University. They published a series of 3,410 patients and found 71% sensitivity, 99% specificity, 87% PPV, and a 2.2% false negative rate. 

These are very disparate numbers. However, the GW study was retrospective and included both pneumothorax and fluid in the abdomen or chest, whereas this abstract looked strictly at pneumothorax and was prospective.

Both studies are interesting on their own, and the presenter of this abstract will need to explain why the results are so different.  The answer to the question of how much we believe the eFAST result remains up in the air!

References:

  1. Lung ultrasound underdiagnoses clinically significant pneumothorax. EAST 2024, Podium paper 21.
  2. eFAST exam errors at a level 1 trauma center: A retrospective cohort study. Am J Emerg Med. 2021 Nov;49:393-398.
Abstracts

Best Of EAST 2024 #4: Chest Tube Irrigation Prevents Retained Hemothorax

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One of the potential complications of chest trauma causing hemothorax is the retained hemothorax. In most patients, retained blood slowly lyses and is reabsorbed. But a few do not, and scarring can occur that entraps the lung and interferes with pulmonary function. This can ultimately require a VATS or thoracotomy to resolve.

Several protocols have been developed to try to prevent a retained hemothorax. They include the use of lytics or an early VATS procedure. The group at the Medical College of Wisconsin performed a trial of thoracic cavity irrigation and compared the outcomes with patients who did not undergo irrigation. This was a single-center retrospective study performed over five years.

This appears to have been a common practice at this institution. Patients undergoing chest tube placement for hemothorax received irrigation of the chest cavity immediately after placement. The study excluded patients with chest tubes placed in other hospitals, tubes placed late (after 24 hours), or patients who had a chest procedure within 6 hours.

Here are the factoids:

  • A total of 370 patients were enrolled, and 225 (61%) received irrigation
  • Demographics of the groups were the same, with the exception that the irrigation group contained more patients with penetrating injury and fewer patients with flail chest
  • Use of irrigation was associated with significantly less incidence of retained hemothorax (10% vs 21%) or need for VATS (6% vs. 19%)
  • Chest tube duration (4 vs 6 days) and hospital length of stay 8 vs 10 days) were also significantly shorter

The authors concluded that irrigation prevents retained hemothorax and decreases the need for surgical intervention.

Bottom line: Well, this was a new one for me. The only prior study I could find was published in 2022 by a group at the University of Nevada at Las Vegas. They irrigated 82 of 198 patients undergoing chest tube placement. They noted a decrease in hospital, ICU, and ventilator days.

This study looks at something far more practical: interruption of the development of a complication. Although still a relatively small and single-institution study, it was well done and could easily detect statistical significance. 

The presenter should be prepared to discuss what impact the mechanism of injury (penetrating, flail chest) may have had on their results and the exact technique they used. How much fluid, what type, and how it was drained are all important questions to discuss.

This is a fascinating abstract indeed. If the presentation answers the questions, centers should consider updating their chest tube management algorithms.

References:

  1. Thoracic cavity irrigation prevents retained hemothorax and decreases surgical intervention in trauma patients. EAST 2024, Podium paper #17.
  2. The Volume of Thoracic Irrigation Is Associated With Length of Stay in Patients With Traumatic Hemothorax. J Surg Res. 2022 Nov;279:62-71.
Abstracts

Coming Soon! The Best Of EAST 2024

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The 37th Annual Assembly of the Eastern Association for the Surgery of Trauma is just around the corner! And, as in previous years, I will be publishing regular posts on some of the abstracts I find the most interesting. Here are some of the topics I’ve selected:

  • MAP and spinal cord injury
  • VTE in pediatric patients
  • Chest irrigation and retained hemothorax
  • Accuracy of eFAST
  • More on the 35mm rule for pneumothorax
  • Pan-scanning and missed injuries
  • King Airway vs i-Gel Airway
  • Whole blood transfusion in pediatric patients
  • Whole blood and VTE risk
  • VTE prophylaxis in patients undergoing acute neurosurgical intervention

For each abstract covered, I will present the findings and give a short critique. Finally, I will provide some questions for the authors to consider, as they very same ones could come from the audience at their presentation!

If you have any particular abstracts you would like me to cover, please list in the comments section below and I will get it on the list!

Abstracts, Resuscitation

Best Of AAST #8: Whole Blood At The Scene Of Injury

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Here’s another abstract with a promising title that suffers from low subject numbers. Whole blood is the new darling of trauma resuscitation. Assembling a unit of whole blood from the components it was broken down into produces an inferior product from the standpoint of resuscitation.

It makes sense from a coagulation standpoint, but there are a few pesky issues that need to be considered, such as antibody titers. So I understand the enthusiasm to get some papers out there that describe the value of it.

A group in the Czech Republic performed a prospective study that assigned patients to receive scene resuscitation with either one unit of packed cells plus one unit of plasma, or two units of low titer group O whole blood. They had a host of primary outcomes, including feasibility, 24-hour and 30-day mortality, 24-hour blood use and fluid balance, and initial INR. They compared the two groups to matched cohort controls from a trauma registry. The study was performed over a three year period.

Here are the factoids:

  • Three groups of about 50 patients each were enrolled
  • There was no difference in 24-hour mortality, but the authors claimed that the 30-day mortality was “better.” However, the numbers were not statistically significant.
  • They found a statistically significant decrease in 24-hour transfusion volume of about 500cc, which is not clinically significant
  • Similarly, there was an increase in fluid balance of about 2L
  • They also found a “significant” decrease in INR from 1.17 to 1.10, which is also not clinically significant
  • There were no transfusion reactions

The authors concluded that whole blood was safe to give at the scene and that there were improvements in the measured parameters.

Bottom line: Sorry, but the abstract does not really support the title. This study is woefully small, and confusing to read. The purpose of the registry control cohort was not clear, and the extra results further muddied the picture. The statistical analyses were not included, and I am skeptical that they fully support the conclusions. There is just no statistical power to achieve significance with the number of subjects in this study. And many of the differences, even if they were statistically significant, were not clinically significant.

I don’t want to be a downer here. I do believe that whole blood is a good thing. Unfortunately, the whole blood in this study could have been better used doing a much bigger, multicenter study to truly show us the benefits.

Reference: Whole blood on the scene of injury improves clinical outcome of the bleeding trauma patient. AAST 2023, Plenary paper #28.

Abstracts, Resuscitation

Best Of AAST #7: How Do You Like Your Platelets – Warm Or Cold?

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Until the last few years, massive transfusion in trauma consisted of component therapy, an admixture of packed red cells, plasma, and platelets. Whole blood transfusion is making inroads again, but it is used in a minority of centers.

Of the three components, platelets have classically required different handling than the others. They are generally kept at room temperature, while the red cells and plasma are kept very cold to preserve their shelf life. A few centers have toyed with the use of cold platelets, but there have been concerns about their ability to clot and their useful life after transfusion.

Researchers from the US Army performed a retrospective registry study on a sample of military casualties over four years. They identified soldiers who received either room-temperature or cold-stored platelets. The primary outcome was mortality, and secondary outcomes included the need for surgery, fluid and blood infusions, and the use of a massive transfusion protocol.

Here are the factoids:

  • A total of 300 patients were identified, nearly equally split between room temp platelets and cold-stored
  • Demographics of the two groups were similar, but the ISS was somewhat higher in the cold-stored platelet group
  • Significantly fewer cold-stored platelet patients underwent surgery (13% vs. 24%)
  • Survival was the same at 87-88%
  • Blood and product administration was significantly higher in the cold-stored group, as was the use of the MTP (54% vs. 34%)

The authors concluded that the use of cold-stored platelets were not inferior to room temperature platelets.

Bottom line: Huh?? Yes, survival was the same despite a higher ISS in the cold platelet group. But they required more blood and needed massive transfusion significantly more often.

I see two major issues with this study. The most important is that it is a non-inferiority study. To believe that both arms are equal, a power analysis is required. The sample size here is too small to achieve significance unless differences are extreme, like the transfusion and MTP numbers.

The second problem is that this is an association study. Attempting to show that the type of platelets used is a major determinant of survival, need for surgery, or blood product use is shortsighted. There are a myriad of other factors that have more of an impact.

Far more subjects need to be studied, and a retrospective study with limited data points is not enough. I’m surprised that a military registry could only come up with 75 patients a year to analyze. These low numbers and the nature of this particular registry could inject significant bias as well.

Stay with the room temp platelets for now, and wait for a well-powered prospective analysis before changing your MTP.

Reference: An analysis of the use of cold-stored platelets in combat trauma. AAST 2023 Plenary paper #29.