Tag Archives: AAST2022

Abstracts, Solid organ

Best Of AAST 2022 #6: The “Missed” Splenic Pseudoaneurysm

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Like so many things in trauma, there are two camps when it comes to repeat CT scan after solid organ injury: the believers vs the non-believers. In my experience, a minority of US trauma centers incorporate this repeat CT study in their practice guidelines. 

Yet the question keeps coming up in the literature. Earlier this year, I reviewed a paper from the University of Cincinnati from a group of believers. I was not very kind, and you can read the review here. The biggest problem with most believer papers is that they cite very old literature that overstates the incidence of delayed hemorrhage. They then use this to justify an extra CT scan to find more of these “dangerous” pseudoaneurysms. Unfortunately, those old papers are just not very good and many overstate the problem.

So let’s look at this year’s abstract from the LAC+USC group. They open by stating that the natural history is unclear but that “risk for spontaneous rupture and exsanguination exist.” The authors sought to further define the utility of using a delayed CT angiogram (dCTA) in diagnosing and triggering intervention after high-grade blunt solid organ injury.

They performed a retrospective study of all patients arriving at their Level I center over a nearly five year period with a Grade 3 or higher injury to liver, spleen, or kidney. They excluded the young, patients transferred in, early deaths, and patients who underwent immediate operation on their spleen or kidney. The primary outcome was intervention triggered by the dCTA.

Here are the factoids:

  • A total of 349 patients with 395 high grade solid organ injuries were analyzed (42% liver, 30% spleen, 28% kidney)
  • Median injury grade for each organ was 3
  • Initial management was “typically” nonoperative or angioembolization (liver 83%, spleen 95%, kidney 89%)
  • Delayed CT angiogram was typically performed on day 4 and identified a lesion in 16 spleen, 10 liver, and 6 renal injuries
  • The dCTA prompted an intervention in 12 spleen, 8 liver, and 5 kidney injuries

The authors conclude that delayed CTA identified a significant number of vascular lesions requiring endovascular or surgical intervention. They recommend further examination and consideration of universal screening to avoid missing these pesky pseudoaneurysms.

Bottom line: Once again, we have a paper that conflates finding a pseudoaneurysm with the need to get rid of it. Granted, I was always taught that pseudoaneurysms (in adults) found on initial CT required an intervention. In the old days of “delayed splenic rupture” a pseudoaneurysm was the likely culprit. 

But the majority of centers do not go looking for pseudoaneurysms days later. And there are precious few patients coming back with delayed hemorrhage after discharge. So what gives?

Could it be that there is a difference between a “fresh” pseudoaneurysm and a “delayed” one? Perhaps the fresh ones portend a real risk of bleeding, but delayed ones are just a normal part of the healing process and rarely bleed? We just don’t know for sure.

This paper shows that if you look for a delayed pseudoaneurysm you will find them. And at this center, if you find them you will be compelled to angioembolize or even operate on them. Yet we really don’t know if that is necessary. It certainly adds to length of stay and hospital charges.

My take is that we desperately need a broad tally of patients discharged with a liver or spleen injury who return within a few weeks for bleeding complications. I would exclude kidneys because they act so differently. And I would not look at all returns because most liver injury readmissions are for bile problems. Just focus on readmissions for bleeding. Once we see what the real incidence is, we can decide whether these pseudoaneurysms are a problem significant enough to pursue with delayed scans, etc.

Here are my questions for the authors and presenter:

  1. What is your assessment of the incidence of delayed rupture and exsanguination? Have you read through the old papers in detail to assure yourselves that they are actually correct?
  2. Do you hold patients in the hospital for their delayed CT angiogram? The studies were typically performed on days 3-7. Do you really keep your solid organ injured patients in the hospital that long? At our center, a grade 3 injury could be discharged home in two days!
  3. How do you decide to take a patient to interventional radiology or the OR after the delayed CT? Is it an unwritten rule? It seemed like most, but not all, had some type of intervention. A (very) few had the lesion but nothing was done. Please explain the difference.

This is an interesting paper just because of the intuitive leap it makes from pseudoaneurysm to intervention. I’m anticipating your presentation so I can hear all the details.

Reference: PSEUDOANEURYSMS AFTER HIGH GRADE BLUNT SOLID ORGAN INJURY AND THE UTILITY OF DELAYED CT ANGIOGRAPHY. Plenary paper #34, AAST 2022.

Abstracts, Imaging

Best of AAST 2022 #4: The “Hybrid ER” – Again?

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Two years ago, an abstract was presented at this meeting describing the concept of the “hybrid ER.” Check it out using this link. This concept was pioneered in Japan, and consists of a special trauma resuscitation room in the ED with everything but an operating room built into it. It’s possible to perform whole-body CT scan, interventional procedures, and REBOA without moving the patient. Here’s a picture from that abstract:

A = CT scanner   B = CT exam table   C = movable C-arm   D = monitor screen   E = ultrasound   F = ventilator

In that abstract, about a thousand patients were compared with two thirds in the hybrid ER group and one third undergoing conventional evaluation. The authors concluded that mortality was significantly improved in the hybrid ER group, and even more so in high ISS patients.

I had a lot of questions for that abstract that were answered in the subsequently published manuscript (reference 2). The authors have updated their experience using new data from the last five years. They created a new approach to resuscitation that is different than the usual ATLS sequence for select patients. Here’s the algorithm they used:

The primary survey is completed, then the patient undergoes a quick whole body CT scan. After that, the secondary survey progresses and any necessary emergency procedures are performed.

In this abstract, the authors compared a group of 46 patients who underwent standard ATLS evaluation with 49 who received the expedited process, which they termed CT First Resuscitation (CTFR). All patients had presumptive hemorrhagic shock based on prehospital vital signs. The authors analyzed injury patterns, interventions performed, timing, adverse events, and outcome. Demographics and injury severity were similar in the two groups.

Here are the factoids:

  • Time to CT in the CTFR group was significantly shorter (1.5 min vs 15 min)
  • The expedited scan settings for CTFR resulted in blindingly fast scan times (median 56 seconds)
  • None of the CTFR patients decompensated during the scan process
  • There was no difference in mortality between CTFR and standard evaluation (14% vs 4%, p=.1)
  • There was no difference in time to hemostatic intervention (56 vs 59 minutes)
  • There was no difference in red cell transfusions (no units in either group)

The authors concluded that CTFR expedited trauma management without adverse effects, and there was no increase in mortality. They, or course, recommended further study.

Bottom line: Several trauma surgeons from a variety of centers wrote an invited commentary last year (reference 3) expressing their excitement about this concept. Reducing time to definitive control of hemorrhage has been repeatedly shown to improve survival. The hybrid ER is one way of reducing those times by eliminating most of the time needed to move the patient about and providing everything but an operating room in the emergency department.

But they also recognized the limitations of this concept. The changes to the ED physical plant are extreme and involve the installation of very expensive equipment that must be heavily shielded from the rest of the emergency department. There are also significant differences in physician training and hospital reimbursement between Japan and the US. This will probably severely limit the adoption of this technology in the States.

I believe that this is an important study showing the feasibility of this method of evaluation. Unfortunately, it does not allow us to draw any real conclusions about safety and efficacy due to the low numbers of patients enrolled. I agree with the authors that a larger study should be performed so we can truly determine whether this concept can possibly be applied outside of Japan.

Here are my questions for the authors / presenter:

  1. Did you perform a power analysis? I doubt that the sample size reported would allow for any findings of statistical significance with the exception of huge differences like time to CT.
  2. How do you protect the trauma team from radiation exposure? Since these patients are in shock when they arrive, I assume that the team cannot leave the room. CT scan radiation exposure of the team is significantly higher than a chest and pelvis x-ray. Repeated team exposure may pose risks.
  3. Does the trend toward higher mortality in the CTFR group trouble you? Sure, it is not statistically significant. But it is approaching significance with a small sample group.
  4. Why didn’t the CTFR group have more rapid hemostatic intervention? One would think these early results could help move the patient to an OR more quickly. And why did it take an hour? Isn’t that a long time?
  5. Why didn’t your patients receive any blood? Weren’t they supposed to be at risk for hemorrhagic shock? How did you treat it without blood? Perhaps your selection criteria need to be tweaked.

This is a nice follow on study from the previous presentation two years ago. It could be an exciting advance in resuscitation, but we need much more info to pass judgement. I’m looking forward to the presentation.

References:

  1. COMPUTED TOMOGRAPHY FIRST RESUSCITATION WITH HYBRID EMERGENCY ROOM FOR SEVERELY INJURED PATIENTS. Plenary paper #25, AAST 2022.
  2. Hybrid emergency room shows maximum effect on trauma resuscitation when used in patients with higher severity. J Trauma Acute Care Surg. 2021 Feb 1;90(2):232-239.
  3. Time to Hemorrhage Control in a Hybrid ER System: Is It Time to Change? Shock. 2021 Dec 1;56(1S):16-21.
Abstracts, Prevention

Best of AAST 2022 #3: VTE Risk After Spinal Cord Injury

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Venous thromboembolism (VTE) is always a concern in trauma patients. But patients with spine fractures are at much higher risk and those with spinal cord injuries on top of it even more so. The best tool we have right now for prevention is chemoprophylaxis with some type of heparin. Unfortunately, VTE prophylaxis is commonly interrupted or delayed due to concern for causing bleeding. These concerns may relate to concomitant injuries (e.g. solid organ injury) or necessary surgical procedures.

About five years ago, the Army provided a $4.25M grant to fund the Coalition of Leaders in Thromboembolism (CLOTT) study group. It involved contributions from 17 Level I trauma centers attempting to look at the incidence, treatment, and prevention of VTE after trauma. Additional phases are now under way to look at offshoot discoveries from the original research.

A group from the University of California – Sand Diego performed a secondary analysis of a subset of the CLOTT study in patients age 18-40 over a three year period. Patients with a diagnosis of spinal cord injury who were admitted for at least 48 hours were analyzed. The authors focused on timing of the start of VTE prophylaxis, VTE rates, and missed prophylactic dosing. They also reviewed any bleeding complications.

Here are the factoids:

  • From the entire CLOTT study group, 343 met criteria and had sustained a spinal cord injury
  • Most subjects were young (mean 29) and male (77%) and had sustained blunt injury (79%)
  • A total of 44 patients (13%) developed VTE – 30 DVT, 3 pulmonary embolism, and 11 pulmonary thrombus
  • Only one in five patients started chemo-prophylaxis prior to 24 hours, and this increased to about 50% at 48 hours (!)
  • VTE rate overall was 9.6% (?)
  • The rate trended lower in patients who received their prophylaxis within 48 hours (7% vs 13% but not significant)
  • Missed doses of chemo-prophylaxis were common (30%) and were associated with higher VTE rates

The authors concluded that VTE rates are high in these patients and early chemoprophylaxis is critical in limiting thrombotic events.

Bottom line: Hmm. This abstract confuses me a little. Actually, I had expected a higher VTE rate in this patient group. I’ve seen reports 2x to 3x higher than reported here. But yes, I do believe that these patients are at high risk.

And looking at the chart, it appears that there is a trend toward higher rates in patients who missed doses rather than those who did not. But the real questions are:

  1. Is it real? That is, are those differences significant? The only analysis in the abstract compares early vs late administration and that is trending toward significance but didn’t quite make it there. And remember that the graph you are looking at cuts off at 18% which makes the differences look much bigger.
  2. What can we do about it? Many trauma professionals are still uncomfortable giving prophylaxis early because of fear of bleeding. This is probably unwarranted, but we just don’t have enough hard data to say so. Anecdotal data about surgeons operating uneventfully through chemoprophylaxis is growing, though.

My impression of this study is that it shows some interesting trends, but probably doesn’t include enough subjects to know the real answer for sure. 

Here are my questions for the authors / presenter:

  1. Tell us about the statistics. How did you calculate the rates that are cited in the paper? I can’t figure out the math.
  2. What is the difference between a pulmonary embolism and pulmonary thrombus? Is it merely the presence or absence of concomitant clot in the legs or pelvis? Why distinguish between the two if you are lumping them all together as “VTE?”
  3. What are we to do with this data? Obviously, everyone wants to provide VTE prophylaxis in a timely manner. But there are a raft of reasons why clinicians are “not comfortable” doing it. Any suggestions?

Reference: VENOUS THROMBOEMBOLISM RISK AFTER SPINAL CORD INJURY: A SECONDARY ANALYSIS OF THE CLOTT STUDY. Plenary Paper 23, AAST 2022.

 

Abstracts, Trauma Center

Best of AAST 2022 #2: How Much Does It Cost To Be A Trauma Center?

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Becoming and remaining a trauma center is an expensive proposition. Some components can pay for themselves (surgical specialists and operating rooms) but others are required yet generate no revenue. These costs must somehow be offset for a trauma center to remain viable.

How much does it actually cost? There have been two papers that deal with this topic (see references). One was published way back in 2004 and examined readiness costs averaged across 10 Florida trauma centers. They comingled data for these hospitals, which were a mix of adult, pediatric, Level I and Level II centers. They arrived at a median annual cost of readiness of $2.1 million.

A similar study was published in 2017 for Level I and Level II centers in Georgia. They were ultimately able to estimate that the annual average readiness cost for Level I centers was $6.8 million, and for Level II centers was $2.3 million.

That’s a lot of money! These hospitals tend to be larger and have specialty centers that allow them to generate enough revenue to support the non-revenue parts of the trauma program.

But what about Level III and Level IV centers? They are generally much smaller hospitals. In many more rural states they are critical access hospitals with 25 or fewer beds. They don’t have a wealth of other programs that can generate significant excess revenue.

So how much does it cost them?  A group at Mercer University in Atlanta attempted to quantify this issue. They developed a survey tool along the lines of the previous work. They sent this to all 14 Level III and Level IV trauma centers in the state, who based their numbers on 2019 data.

Here are the factoids:

  • For Level III centers, the average annual readiness cost was $1.7 million
  • The most expensive components for Level III centers were for clinical medical staff. This was most likely related to stipends for service / call coverage.
  • For Level IV centers, the cost was only $82 thousand and primarily involved administrative costs (most likely trauma program personnel)
  • Education and outreach programs are mandated for these centers but the centers actually spent only $8,000 annually. The authors believe this represented significant under-resourcing by the hospitals.

The authors concluded that there is a need for additional trauma center funding to enable Level III and IV centers to meet the requirements set forth by the American College of Surgeons.

My comments: This is a very enlightening paper on the cost of being a trauma center. Only two papers have previously explored this, and only for higher level centers. However, the devil is in the details. The nuts and bolts numbers and the assumptions made on how they fit together are key. But it does provide some enlightening information on what it costs to be a trauma center. And the disparity between the two levels is fascinating / frightening.

Here are my questions for the authors / presenters:

  • What assumptions did you have to make to arrive at these numbers? Please explain the details of your model and where you think the weaknesses in it may lie.
  • Why is it so much more expensive to be a Level III center? The abstract places the blame on “clinical medical staff.” Are these on-call stipends or something else?
  • What would you tell wannabe Level III or IV centers looking to become a trauma center? Unfortunately, these numbers might scare some of the off.

Thanks for an intriguing and challenging paper! The discussion will be very interesting!

References: 

  1. ASSESSING TRAUMA READINESS COSTS IN LEVEL III AND LEVEL IV TRAUMA CENTERS. Plenary session paper #10, AAST 2022.
  2. The cost of trauma center readiness. Am J Surg 187(1):7-13, 2004.
  3. What Are the Costs of Trauma Center Readiness? Defining and Standardizing Readiness Costs for Trauma Centers Statewide. Am Surg 83(9):979-990, 2017.

 

Abstracts, Complications

Best of AAST 2022 #1: The Trauma-Specific Frailty Index (TSFI)

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Let’s start with the paper that is kicking off the 81st Annual Meeting for the AAST. Everyone recognizes that many of our elderly patients don’t do well after trauma. Unfortunately, elderly is a very imprecise term. According to the TRISS method for predicting mortality it begins at age 55. But we have all seen many patients younger than that who appear much older physiologically. And a few older ones who are in excellent condition.

How can we determine who is frail and thus more likely to develop complications or even die after injury? The trauma group at the University of Arizona – Tucson published their original paper on a 50-variable frailty index in 2014 in order to address this issue. Unfortunately, 50 variables were found to be very unwieldy, which vastly decreased its usability.

They immediately decided to strip it down to the most significant 15 variables, and named it the Trauma-Specific Frailty Index. This tool simply predicted whether the patient would have a favorable discharge (home), or an unfavorable one (skilled nursing facility or death). The TSFI was very good at this, and was far better than using age alone.

The authors rolled the TFSI out to the AAST multi-institutional study group. A total of 17 Level I and II trauma centers participated in a three-year prospective, observational study. All patients with age > 65 had their TFSI calculated. They were stratified into three groups, including non-frail, pre-frail, and frail. The outcomes studied were expanded and included mortality, complications, discharge status, and 3 month status for readmission, falls, complications, and death.

Here are the factoids:

  • A total of 1,321 patients were enrolled across all centers with a mean age of 77 and median ISS 9
  • A third each were classified as non-frail, pre-frail, and frail
  • The overall study group had a 5% mortality, 14% complication rate, and 42% unfavorable discharge rate
  • Frail patients had a higher complication rate vs the pre- and non-frail groups (21% vs 14% vs10%) which was significant
  • They also had a higher mortality rate (7% vs 3% vs 4%) with p=0.048 although significant on multivariate analysis
  • Overall, 16% were readmitted within 3 months and 2% died. This was not stratified in the abstract by frailty group.

The authors claim that the TFSI is an independent predictor of worse outcomes, and that it is practical and effective and should be used in the management of geriatric trauma patients.

Comments: I find the concept of the abstract very interesting. I think most of us can identify the obviously frail patients when we see them. The TFSI promises more objective identification  using 15 variables. For reference, here they are:

  • Comorbidities
    • Cancer history
    • Coronary heart disease
    • Dementia
  • Daily activities
    • Help with grooming
    • Help with managing money
    • Help doing housework
    • Help toileting
    • Help walking
  • Health attitude
    • Feel less useful
    • Feel sad
    • Feel effort to do everything
    • Falls
    • Feel lonely
  • Sexual function
  • Serum albumin

The authors showed that all of the outcomes were significantly and negatively associated with the patient’s frailty index. The analysis appears reasonable, and the numbers are both statistically and clinically significant. 

But the big question now is, how do we use the results? The 15-variable version is reasonably workable. Is it any better than the trauma professional walking into a room and doing a good eyeball test? The study did not look at that. Either way, what can we do when we identify the truly frail patient? What can we alter in the hospital care that might make a difference? Right now, options are limited. Much of what led to the patient’s frailty is water under the bridge due to possibly decades of lifestyle choice or pre-existing disease.

I think that the next step in this train of thought is to start applying specific interventions in patients identified as frail or better yet, pre-frail. Here are my questions for the authors and presenter:

  1. What’s next? You’ve shown that you have a numerical tool that identifies patients who may have a less than desirable outcome. If we implement this, what can we do to try to reduce those undesirable outcomes?

This was thought provoking work, and I am looking forward to the full presentation!

Reference: PROSPECTIVE VALIDATION AND APPLICATION OF THE TRAUMA SPECIFIC FRAILTY INDEX: RESULTS OF AN AAST MULTI-INSTITUTIONAL OBSERVATIONAL TRIAL. AAST 2022 Plenary Paper 1.