Tag Archives: spleen

Does Time To Interventional Radiography Make a Difference In Solid Organ Injury?

Solid organ injury is one of the more common manifestations of blunt abdominal trauma. Most trauma centers have some sort of practice guideline for managing these injuries. Frequently, interventional radiology (IR) and angioembolization (AE) are part of this algorithm, especially when active bleeding is noted on CT scan.

So it makes sense that getting to IR in a timely manner would serve to stop the bleeding sooner and help the patient. But in most hospitals, interventional radiology is not in-house 24/7. Calls after hours require mobilization of a call team, which may be costly and take time.

For this reason, it is important to know if rapid access to angioembolization makes sense. Couldn’t the patient just wait until the start of business the next morning when the IR team normally arrives?

The group at the University of Arizona at Tucson tackled this problem. They performed a 4-year retrospective review of the TQIP database. They included all adult patients who underwent AE within four hours of admission. Outcome measures were 24-hour mortality, blood product usage, and in-hospital mortality.

Here are the factoids:

  • Out of over a million records in the database, only 924 met the inclusion criteria
  • Mean time to AE was 2 hours and 22 minutes, with 92% of patients getting this procedure more than an hour after arrival
  • Average 24-hour mortality was 5%. Mortality by hours to AE was as follows:
    • Within 1 hour: 2.6%
    • Within 2 hours: 3.6%
    • Within 3 hours: 4.0%
    • Within 4 hours: 8.8%
  • There was no difference in the use of blood products

The authors concluded that delayed angioembolization for solid organ injury is associated with increased mortality but no increase in blood product usage. They recommend that improving time to AE is a worthy performance improvement project.

Bottom line: This study has the usual limitations of a retrospective database review. But it is really the only way to obtain the range of data needed for the analysis. 

The results seem straightforward: early angioembolization saves lives. What puzzles me is that these patients should be bleeding from their solid organ injury. Yet longer delays did not result in the use of more blood products.

There are two possibilities for this: there are other important factors that were not accounted for, or the sample size was too small to identify a difference. As we know, there are huge variations in how clinicians choose to administer blood products. This could easily account for the apparent similarities between products given at various time intervals to AE.

My advice? Act like your patient is bleeding to death. If the CT scan indicates that they have active extravasation, they actually are. If a parenchymal pseudoaneurysm is present, they are about to. So call in your IR team immediately! Minutes count!

Reference: Angioembolization in intra-abdominal solid organ injury:
Does delay in angioembolization affect outcomes?  J Trauma 89(4):723-729, 2020.

Best of AAST #12: Embolization Of Splenic Pseudoaneurysm

The management of blunt spleen injury has evolved significant over the time I’ve been in practice. Initially, the usual formula was:

Spleen injury = splenectomy

This began to change in the late 1980’s, and beginning in the early 90’s nonoperative management became the rage. We spent the next 10-15 years tweaking the details, gradually reducing bed rest and NPO times, and increasing the success rate through smart patient selection and discovering new adjuncts.

One of these adjuncts was angiography with embolization. The ShockTrauma Center in Maryland was an early adopter and protocolized its use in patients with high-grade injuries.

But now, they are questioning the utility of this tool in certain patients: those with splenic pseudoaneurysms (PSA). They theorized that modern, high resolution CT identifies relatively unimportant pseudoaneurysms. They conducted a 5-year retrospective review of their experience.

Here are the factoids:

  • They identified 717 splenic injuries, of whom 155 were embolized but only 140 patients had adequate records and imaging for review
  • The majority of patients had high grade injury: 31% Grade 3, 61% Grade 4, 1% Grade 5
  • Extravasation was seen in 17% and PSA in 52%
  • About 44% of patients went to angiography within 6 hours, but the mean was 17 hours indicating quite a few outliers
  • Among the 73 patients with an initial PSA , a third of them did not have a detectable lesion during angiography
  • Patients who underwent embolization for PSA had a followup CT 48-72 hours afterwards, persistently perfused PSA were seen in 40% (!)
  • No patients with PSA who were only observed required delayed splenectomy

The authors conclude that a third of pseudoaneurysms may be clinically insignificant, and that 40% of them persist after embolization. They do not, however, offer any recommendations based on their data.

Here are my comments: This is an interesting study. My read of the abstract and slides would indicate that this group routinely sends all Grade 3 and 4 injuries to angio, and Grade 5 could go to either angio or OR. They take their good time going to interventional radiology (mean 17 hours from arrival), and get a routine followup CT 48-72 hours from hitting the door if they didn’t go to the OR.

If I were to play the devil’s advocate, I might think that interventional radiology was being de-emphasized for some reason. Was there some reluctance to send patients there, or limited availability? This might explain the long access times. And how are the radiologists not shutting down 40% of PSA that are seen?

I am intrigued by the study, but there are a lot more details needed to get some good takeaways from it.

Here are my questions for the presenter and authors:

  • Please explain why it takes so long to send patients to angiography. Less than half got there in less than 6 hours, and the mean of 17 hours means that many didn’t get there until the next day.
  • Does this small study have the statistical power to say that some PSA are benign? The groups are very small, and I would speculate that the group size needed to show significance is in the high hundreds.
  • What was the reason for splenectomy in the 2 patients who underwent embolization? Was it related to the pseudoaneurysm or something else?
  • How can you be sure that these PSA are insignificant? Frequently, pseudoaneurysms don’t explode for 7-10 days. Do you have any data on patients who returned to a hospital with delayed bleeding?
  • If you believe that many pseudoaneurysms are benign, how do you propose to manage the patients? Observe until they explode? Repeat a contrast CT scan, with the associated contrast and radiation re-dose? And how long would you wait to do this? What would your new protocol be?

I’ll be all ears on Friday when this abstract is presented live.

Activity Guidelines After Solid Organ Injury: How Important Are They?

Just about every practice guideline out there regarding liver and spleen injury has some type of physical activity guidelines associated with it. The accepted dogma is that moving around too much, or climbing stairs, or lifting objects, or getting tackled while playing rugby could exacerbate the injury and lead to complications or surgery.

But is it true? Activity restrictions after solid organ injury have been around longer than I have been a trauma surgeon. And the more people I poll on what they do, the more and very different answers I get. And there are no decent papers published that look critically at this question. Until now. 

A pediatric multi-center study of study on adherence to activity restrictions was published last year. Ten Level I pediatric trauma centers in the US tabulated their experience with solid organ injuries over a 3.75 year period fro 2013 to 2016. Only patients with successful nonoperative management of their injury were included, and those with high grade renal or pancreatic injuries were excluded.

Since this was a pediatric study, the American Pediatric Surgical Association (APSA) practice guideline was followed (activity restriction = organ injury grade + 2 weeks). Activity restrictions included all sports, any recreational activity with wheels, or any activity that involved having both feet off the ground. Patients with Grade III-V injuries were seen at an office visit after 2 weeks, and lower grade injuries had a phone followup.

Adherence to guidelines was assessed by a followup phone call two months after injury. Clinical outcomes assessed at 60 days included unplanned return to the emergency department (ED), re-admission, complications, and development of new bleeding confirmed by surgery, ultrasound, or computed tomography (CT) at 60 days post injury.

Here are the factoids:

  • Of the 1007 patients in the study, some 56% were either excluded (178) or lost to followup (463)
  • Of the remaining 366, roughly 46% had a liver injury, 44% spleen, and the remaining 10% had both
  • Median age was 10, so this was actually a younger population
  • 76% of patients claimed they abided by the guidelines, 14% said they did not, and 10% “didn’t know.” This means they probably did not.
  • For the 279 patients who said they adhered to activity restrictions 13% returned to the ED and half were admitted to the hospital
  • Of the 49 patients who admitted they did not follow the guidelines, 8% returned to the ED at some point and none were readmitted
  • The most common reasons for return to ED were abdominal pain, anorexia, fatigue, dizziness, and shoulder pain
  • There were no delayed operations in either of the groups

Bottom line: There were no significant differences between the compliant and noncompliant groups. Unfortunately, the authors did not include an analysis of the “I don’t know if I complied” group, which would have been interesting. But there is one issue I always worry about in these low-number-of-subjects studies that don’t show a significant difference between groups. Did they have the statistical power to show such a difference? If not, then we still don’t know the answer. And unfortunately, I’m not able to guess the numbers well enough to do the power calculation for this study.

I am still intrigued by this study! Our group originally had a fixed time period (6 weeks) of limited activity in our practice guideline for pediatric solid organ injury patients. This was rescinded last year based on our experience of no delayed complications and guidance from our sister pediatric trauma center at Children’s Hospital in Minneapolis. We are also moving toward making a similar change on our adult practice guideline.

Too many centers wait too long to make changes in their practice guidelines. They bide their time waiting for new, published research that they can lean on for their changes. Unfortunately, I think they will be waiting for a long time because many of our questions are not interesting enough for acceptance by the usual journals. Rely on the expertise and experience of your colleagues and then make those changes. Be sure to follow with your performance improvement program to make sure that they actually do work as well as you think!

Reference: Adherence to APSA activity restriction guidelines and 60-day clinical outcomes for pediatric blunt liver and splenic injuries (BLSI). J Ped Surg 54:335-339, 2019.

Spleen Vaccines: So Confusing! – Part 2

Who needs to get these vaccines? Obviously if your patient’s spleen was surgically removed, they should get it. But what about patients who underwent angioembolization? Unfortunately, the only data available is either very old or is based on antibody response to the vaccine. And antibody titers do not predict immunity to infection, so these studies are close to meaningless.

Old research showed that the spleen’s immune function was preserved as long as 50% of its blood flow was delivered through the splenic artery. How can you tell if half of the spleen is still functioning after splenic angioembolization? Look at the images and make an educated guess. If in doubt, vaccinate.

When is the best time to vaccinate? There has been much gnashing of teeth regarding early vs late vaccination. The arguments against early vaccination center around the typical immune suppression seen with major trauma. However, trauma patients frequently do not appear for all their followup visits and would not receive vaccines at all if they are a no-show. So I recommend vaccinating as early as possible during the hospital stay to avoid forgetting. The data recommending waiting until just before discharge are also based on antibody titers, and I don’t buy it.

Bottom line: I’m not an epidemiologist. But making a set of vaccination rules more complicated for a complex population seems unwise. Especially since the added vaccine offers protection for only one more serotype of Pneumococcus.

But I can’t argue with the FDA and CDC. I have no idea of the wheeling and dealing that occurred to get the new vaccine approved. All we can do is follow the recommendations the best we can, and try to remind our patients to get that Pneumovax and meningococcal conjugate booster five years down the road. Good luck with that.

Spleen Vaccines: So Confusing! – Part 1

Earlier this year, there were a lot of television commercials for Prevnar 13, a 13-valent pneumococcal vaccine for immun-ocompromised or asplenic adults. And interestingly, I noticed that the CDC has added a recommendation that these patients receive this vaccination, followed by the original 23-valent vaccine (Pneumovax 23) 8 weeks later.

WTF? Patients with splenectomy (or significant angio-embolization) for trauma are considered functionally asplenic. And although the data for immunization in this group is weak, giving triple vaccinations with pneumcoccal, H. flu, and meningococcal vaccines has become a standard of care.

This was difficult enough already because there was debate around the best time to administer: during the hospital stay or several weeks later after the immune system depression from trauma had resolved. The unfortunate truth is that many trauma patients never come back for followup, and so don’t get any vaccines if they are not given during the hospital stay.

And then came the recommendation a few years ago to give a 5-year booster for the pneumococcal vaccine. I have a hard time remembering when my last tetanus vaccine was to schedule my own booster. How can I expect my trauma patients to remember and come back for their pneumococcal vaccine booster?

So what do we do with the CDC Prevnar 13 recommendation? If we add it, it means that we give Prevnar while the patient is in the hospital, and then hope they come back 8 weeks later for their Pneumovax. And then 5 years later for the booster dose. Huh?

Looking at the package insert, I read that Pneumovax 23 protects against 23 serotypes of S. Pneumo, which represent 85% of most commonly encountered strains out there. So it’s not perfect. Prevnar 13 protects against 13 serotypes, and there is no in-dication as to what percent of strains encountered are protected against.

So I decided to dig deeper and look at the serotypes included in each vaccine. They are shown in the chart below. The 23 bars with maroon in them (solid or striped) are Pneumococcal serotypes covered by Pneumovax 23. The 13 bars containing gray are ones covered by Prevnar 13. There is only one serotype in Prevnar 13 not covered by Pneumovax 23, serotype 6A. Unfortunately, it’s nearly impossible to find the prevalence of infections by serotype, and it varies geographically and over time anyway. So does cover-age of a single extra serotype by Prevnar 13 justify an additional vaccination and complicated administration schedule? Hmm.

It turns out that there is one significant difference between these two vaccines. Pneumovax 23 is a polysaccharide vaccine made up of fragments of polysaccharide from pneumococcus cell walls. Prevnar 13 is a “conjugated vaccine,” meaning that the polysaccharides are linked to a protein. This is thought to increase the immune system response to the vaccine.

(click for full-size graph)

The current CDC recommendations are listed below. In the old days, we just gave three vaccines before the patient left the hospital. Then the Pneumovax 23 booster was added at 5 years. Same for the meningococcal serogroup B booster at 4 weeks. Then the meningococcal conjugate vaccine (Menactra) came along and was added (with a booster at 8 weeks). Finally, Prevnar 13 was added with its own booster, and Pneumovax 23 was delayed for 8 weeks. Oh, and don’t forget the 5 year boosters for both Pneumovax 23 and the meningococcal conjugate vaccines. It has become very complicated.

(click for full-size chart)

In my next post, I’ll try to make sense of this mish-mash and offer some thoughts on how to decide what to do for your patients.