Category Archives: Solid organ

New EAST Practice Guideline: Spleen Vaccines After Angioembolization

I am trying to figure out how I missed it! The Eastern Association for the Surgery of Trauma (EAST) snuck a new practice management guideline into the Injury journal last fall. And it desperately tries to answer a question that has been hanging around for several years. Do we vaccinate spleen injury patients who undergo angioembolization or not?

I’ve been pondering this for some time and have reached my own conclusion based on some very old literature. Decades ago, we figured out that removing the spleen significantly affects immune function. Splenectomy patients are known to be more susceptible to encapsulated bacteria like Neisseria meningiditis, Streptococcus pneumoniae, and Haemophilus influenzae. Most trauma centers routinely vaccinate these patients before they are discharged home.

With the more recent emphasis on splenic salvage and nonoperative management of injury to this organ, angioembolization has become commonplace. This technique can be done in two ways: proximal and distal. Proximal embolization blocks the splenic artery, so there is no further blood flow to the spleen through it. Distal embolization (selective or super-selective) strives to block flow to very specific areas of the organ.

Do we need to give the vaccines if we cut off blood flow to pieces of the spleen or the main splenic artery? Based on my appreciation of very old splenectomy and partial splenectomy papers, it looked like we should in some cases. One report showed that splenic protection from encapsulated bacteria required about 50% of the spleen to be present and perfused by the splenic artery. This caveat stems from a time when we would perform a trauma splenectomy, dice the spleen up on the back table, and then implant a bunch of spleen cubes into the mesentery to try to provide some immune protection. Turns out that the pieces lived but didn’t do a damn thing.

My practice, then, has been to look at the fluoro images and estimate how much of the spleen was left. I would order the vaccines if a main splenic artery embolization (proximal) was performed. If a distal embolization were performed, I would eyeball the amount of devascularized spleen and give the vaccines if it looked like more than half was dark. Not very precise, I know.

But what would EAST say? They tried to perform a systematic review and meta-analysis of studies that compared outcomes in splenectomy vs. angioembolization patients. Unfortunately, there isn’t a lot of research material out there. So they settled on looking at papers that analyzed immune function, typically using B-cells, T-cells, and antibodies. The authors performed two comparisons: angioembolization vs. splenectomy and angioembolization vs. control.

Angioembolization vs. Splenectomy

These papers compared embolization patients who may or may not have spleen function to splenectomy patients who definitely have none. Embolization patients had fewer infectious complications during their hospital stay and better immune function using the indirect methods noted above. Unfortunately, the data quality was poor, with a significant risk of bias. There was no stratification of proximal vs. distal embolization. Nevertheless, this suggests that, at least overall, the embolization patients retained immune function.

Angioembolization vs. Controls

What about comparing embolization patients to spleen-injured patients who did not undergo any procedure? They should have normal function. Again, the quality of the very few papers available was low. But overall, there was no difference in immune function between the groups.

Bottom line: The EAST review team conditionally recommended against routine spleen vaccines after angioembolization for spleen injury. They concluded that immune function was maintained, so it should not be necessary.

What, you ask, about patients with proximal splenic embolization? The reality is that this only stops inflow from the splenic artery, and only for a few days or weeks. It may slowly resume over time. And it does nothing to the inflow from the short gastric arteries. Apparently, this is enough to provide immune protection against infection.

Whether this is actually true is open to debate. We have no idea if the numbers of T- and B-cells seen and the antibody titers are actually enough to avoid overwhelming post-splenectomy sepsis. And unfortunately, this condition is so rare that we will never accumulate enough cases to make a definitive statement.

But for now, it is probably okay to forgo the vaccines in patients undergoing angioembolization. Besides, the differing guidelines on which vaccines to use, when to give them, and when to schedule boosters were getting way out of hand! Please keep it simple!

Reference: Vaccination after spleen embolization: a practice management guideline from the Eastern Association for the Surgery of Trauma. Injury 53:3569-3574, 2022.

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The End Of Serial Hemoglobin/Hematocrit In Solid Organ Injury

Here’s the final post on my series covering serial hemoglobin testing in the management of solid organ injury.

We developed our first iteration of a solid organ injury practice guideline at Regions Hospital way back in 2002. It was borne out of the enormous degree of clinical variability I saw among my partners. We based it on what little was publicly available, including an EAST practice guideline.

Recognizing that the EAST guideline couldn’t dictate bedside care, we gathered together to meld it with our own clinical experience. We fashioned our first practice guideline later that year and tested it.  It included instructions for bedrest (only overnight), vital signs monitoring, and lab testing (on admission and once the next day).

That last bit about serial lab tests is an important one. We had seen anecdotal evidence in our patients that it wasn’t very helpful. For example, I had one patient in the ICU whose serial Hgb had just returned normal. However, a minute later they experienced a hard hypotensive episode, and I took him immediately to the OR and took out a ruptured and bleeding spleen.

I’ve written several posts on how quickly Hgb changes after hemorrhage. Unfortunately, this lab test just lags too long to be a reliable indicator of anything. A very recent study has been published by Texas Health Presbyterian in Dallas. The retrospectively reviewed patients with liver or spleen injury over five years. They examined how often serial hemoglobin determinations influenced management during the study period. Possible interventions were none, operation, angioembolization, or blood transfusion.

Here are the factoids:

  • There were 143 patients enrolled, and half had no interventions, a third had interventions within 4 hours, and the remainder (16%) had an intervention after 4 hours
  • In the early intervention group, one-third underwent laparotomy, 42% angiography, and 9% had both; 17% received transfusions based on clinical parameters alone and not lab results
  • Of the 16% that did have a later intervention (23 patients), 12 received a blood transfusion only based on a Hemoglobin value, and all but one had no further interventions. That patient had a laparotomy based on the lab test.
  • All other patients in the late intervention group went to OR or angioembolization based on hemodynamics or a change in physical exam.
  • The number of blood draws was phenomenal, with an average of 19 in the early intervention group, 17 in the delayed intervention group, and 7 in the no-intervention group

The authors concluded that serial hemoglobin measurements were not well-supported by the literature and that the decision for intervention was nearly always driven by hemodynamics or physical exam.

Bottom line: Although this study is small, the results are very clear. As we were taught in our surgical training, hemodynamics and physical exam are vital in managing solid organ injury. Unfortunately, hemoglobin is a lagging indicator, and the repeated discomfort and unnecessary cost overshadow its clinical value. This is most significant when treating pediatric patients.

Try to recall the last time you and your trauma colleagues had a patient whose need for intervention was based on a lab draw. Now take your practice guideline back to the drawing board and eliminate the serial exams!

Click here for an example of a serial Hgb-free solid organ injury practice guideline

Reference: Role of Serial Phlebotomy in the Management of Blunt
Solid Organ Injury in Adults. J Trauma Nurs 30(3), 135–141, 2023.

 

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Best Of EAST 2023 #10: Early VTE Prophylaxis In Adolescents With Solid Organ Injury

Chemoprophylaxis against venous thromboembolism (VTE) is routine in trauma care. In most cases, it can be initiated shortly after admission in most trauma patients. However, there are a few major exceptions, including eye injuries and brain injuries with intracranial hemorrhage.

Solid organ injury used to be cause for concern when considering prophylaxis, but most trauma centers are now comfortable beginning within 24 to 48 hours after injury. Having said that, those numbers are for adult patients. What about the younger ones?

The University of California Irvine group queried the TQIP database (3 recent years) to examine outcomes for adolescent patients (12-17 years old) given VTE prophylaxis after injury to liver, spleen, and/or kidney. They excluded patients who had TBI, anticoagulation or coagulopathy, immediate laparotomy, transfers in, and patients who died or were discharged within 48 hours. They matched patients for age, comorbidities, grade of injury, overall severity of injury, and hypotension/need for transfusion.

Eligible patients who received chemoprophylaxis early  (within 48 hours) vs. late were reviewed to identify any differences in complications, length of stay, failed non-op management, and mortality.

Here are the factoids:

  • A total of 1,022 cases were isolated from the TQIP database, and 417 adolescent cases were matched to adults
  • VTE rate was statistically the same, 0.6% in the early group vs. 1.7% in the delayed group
  • Failed non-op management was identical at 5.9% vs. 5.6%
  • There was one death in the delayed group and none in the early group (not significant)
  • ICU LOS was the same at 3-4 days
  • One item not mentioned in the body of the abstract: hospital length of stay was significantly longer in the early group: 9 days vs. 6 days

The authors concluded that early VTE prophylaxis in adolescent trauma patients did not increase failure of nonoperative management, nor did it decrease the incidence of VTE.

Bottom line: This is a study that needed to be done. Due to IRB restrictions, it is typically more challenging to perform actual studies on children and adolescents. Retrospective use of databases helps overcome this problem, although it always introduces a few unwanted wrinkles.

We frequently assume that adolescents behave physiologically like adults. Although often true, you can’t always count on it. Those of us who take care of children and young adults know that they tend to do better than adults by most measures. But again, this is an assumption and needed to be studied.

This database study was limited to three years of data and only produced 417 matched cases for study. This is a small number, and I always worry about statistical power. If the results of such a study are negative, one is left wondering if a proper power analysis was done.

One puzzling result left me wondering about the power question. Patients who received early prophylaxis had exactly the same rate of VTE as those who received it late. Adult data indicates that early use should decrease this complication. Is this another indication of a statistical power problem? Would the inclusion of more patients have shown a real difference?

The other result that struck me (and was not commented upon in the body of the abstract) was the statistically significant 50% increase in hospital length of stay for the early prophylaxis group. Is there some unknown variable that was not matched that caused it? This is one of the known pitfalls of these retrospective database studies.

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

  • Broken record question: Did you have enough cases to provide adequate statistical power? This study showed a negative result. Did you have enough matched cases to actually be able to detect a difference if there was one? Why not add a few more years of data and recalculate?
  • How do you explain the failure of early VTE prophylaxis to protect these patients from DVT or PE? Is this also a statistical power problem?
  • Why is the hospital length of stay significantly longer in the early prophylaxis group?

This intriguing paper follows my bias toward treating these patients exactly the same as adults with early chemoprophylaxis. I just need a few of the loose ends tied up.

Reference: SIMILAR RATE OF VENOUS THROMBOEMBOLISM AND FAILURE OF NON-OPERATIVE MANAGEMENT FOR EARLY VERSUS DELAYED VTE CHEMOPROPHYLAXIS IN ADOLESCENT BLUNT SOLID ORGAN INJURIES: A PROPENSITY-MATCHED ANALYSIS. EAST 2023 Podium paper #27.

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

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.

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Surveillance For Splenic Pseudoaneurysm After Injury

When it comes to repeat CT scanning after splenic injury, there are believers and there are non-believers. In my experience, the majority of centers in the US are non-believers. However, there is a new paper in press that attempts to convince us that more should become believers.

I think the biggest lesson to be learned from this paper is that WE SHOULD READ THE ENTIRE PAPER before drawing conclusions. I have said this in the past and I will say it again. In this case, not only did I read the entire paper, but I had to dig deep into the references it cited as well.

Nonoperative management of splenic injuries has a very high success rate if done properly. Some papers claim this can be up to 93%, which parallels my experience. This success rate involves excluding unstable patients (they need to be in the operating room) and planned use of angioembolization in select patients. Over the years we have found that we need to do less and less in the management of solid organ injury patients:

  • No bedrest
  • No starvation (NPO status)
  • No serial blood draws
  • No repeat CT scan
  • Few limitations on activity after discharge

For an example of a practice guideline that demonstrates that less is more, use the download link at the end of this post.

But back to the question about repeat CT scanning before discharge. Why do we need to do this? The usual reason is that “we want to find delayed pseudoaneurysms.” And why is that important? “It might bleed!”

Really? Let’s look into that through the lens of this new paper by the group at the University of Cincinnati. They performed a retrospective study of their experience with patients who had sustained blunt splenic injury during a recent three-year period. They were interested in how many underwent splenectomy or splenorrhaphy, who had repeat CT imaging, who went to interventional radiology (IR) and when, and which ones were found to have pseudoaneurysms and what was done about it.

Here are the factoids:

  • There were 539 patients who met inclusion criteria, with an average ISS of 24
  • Of these, 46 died during their hospital stay (none from their splenic injury)
  • Focusing on the 248 patients with higher grade injuries (III-V), 125 (50%) underwent emergent or delayed splenectomy. Early vs late operation was not broken out, but this is a startlingly high number!
  • Of the higher grade injured patients who kept their spleens, 97% underwent repeat CT around day 5
  • Delayed pseudoaneurysms were detected in the following patients:
    • Grade III: 10 of 88 patients (11%). Then 8 of those 10 went to IR, and 5  of 10 had splenectomy!
    • Grade IV: 7 of 24 (29%).  Then 8 of the 7 (error in the paper?) went to IR and 3 of 7 had splenectomy!
    • Grade V: 2 of 5 (40%). Both of these patients went to IR and somehow kept their spleens.

The authors conclude that routine followup CT imaging identifies splenic pseudoaneurysms allowing for interventions to minimize delayed complications.

Bottom line: Whoa! There’s a lot going on here. My first observation is that this center does a lot of splenectomies! Of the 539 patients (all comers) who were included in the study, 129 (24%)  lost their spleens. If grade I-II injuries are excluded that percent rises to 50%!

Only eight splenectomies were performed after the repeat CT. This would imply that there were either a lot of unstable patients with splenic injury, the institutional indications for this procedure arbitrarily include grade, or there is a lot of variability in the decision to perform it.

I think there are really two questions to answer here. 

  1. Does delayed splenic pseudoaneurysm occur? The answer is yes. There are a few studies (performed by believers) that demonstrate new pseudoaneurysms after repeat CT. I’m convinced.
  2. Do we care? The real question is, do these pseudoaneurysms cause harm? The fear is that they might explode at some point after patient discharge and cause a major problem.

Papers written by the believers cite a number of old studies and give numbers between 2% and 27% for incidence of delayed hemorrhage. Well, I tracked down all of these papers, including the ones they cited. And it doesn’t add up.

  • One paper from a believer institution found no delayed bleeds.
  • Several papers were for pediatric patients, whose spleens don’t behave like adult ones. They found one case after discharge in one out of 276 patients across three studies.
  • Of 76 adolescents, none encountered delayed bleeds

Many of the papers cited regarding bleeding complications are very old. CT scanners had less resolution, and in many papers, IR was not even a consideration. 

So here’s my take. Yes, delayed pseudoaneurysms occur. In children we don’t care. They almost never cause a problem. But in adults, they can and do cause issues and should be embolized shortly after the initial scan. 

Once embolized, the ones seen on that initial scan are effectively neutralized and do not need a repeat scan. The small ones that might pop up later may very well be part of the healing process. And they may not even occur if angioembolization is done early. It seems unlikely that anything further is needed.

But remember, clinical judgement trumps all. If your patient starts complaining of new abdominal symptoms while in the hospital or after discharge, get a prompt CT scan to rule out any developing complications.

Sample solid organ injury protocol: click here

Reference: Delayed splenic pseudoaneurysm identification with surveillance imaging. J Trauma Acute Care Surg. 2022 Mar 22. doi: 10.1097/TA.0000000000003615. Epub ahead of print. PMID: 35319540.

 

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