Category Archives: Complications

How To Predict Venous Thromboembolism In Pediatric Trauma

As with adults a decade ago, the incidence of venous thromboembolism (VTE) in children is now on the rise. Whereas adult VTE occurs in more than 20% of adult trauma patients without appropriate prophylaxis, it is only about 1% in kids, but increasing. There was a big push in the early 2000′s to develop screening criteria and appropriate methods to prevent VTE. But since the incidence in children was so low, there was no impetus to do the same for children.

The group at OHSU in Portland worked with a number of other US trauma centers, and created some logistic regression equations based on a large dataset from the NTDB. The authors developed and tested 5 different models, each more complex than the last. They ultimately selected a model that provided the best fit with the fewest number of variables.

The tool consists of a list of risk factors, each with an assigned point value. The total point value is then identified on a chart of the regression equation, which shows the risk of VTE in percent.

Here are the factors:

Note that the highest risk factors are age >= 13, ICU admission, and major surgery.

And here is the regression chart:

Bottom line: This is a nice tool, and it’s time for some clinical validation. So now all we have to do is figure out how much risk is too much, and determine which prophylactic tools to use at what level. The key to making this clinically usable is to have a readily available “VTE Risk Calculator” available at your fingertips to do the grunt work. Hmm, maybe I’ll chat with the authors and help develop one!

Reference: A Clinical Tool for the Prediction of Venous Thromboembolism in Pediatric Trauma Patients. JAMA Surg 151(1):50-57, 2016.

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Overwhelming Post-Splenectomy Infection (OPSI)

Most trauma professionals have heard of OPSI, but few have ever seen it. The condition was first described in splenectomized children in 1952. Soon after, it was recognized that this infection occurred in asplenic adults as well.

OPSI is principally due to infection by encapsulated organisms, those with a special polysaccharide layer outside of the bacterial wall. This layer is only weakly immunogenic, and confers protection from the normal immune mechanisms, particularly phagocytosis. However, these bacteria are more easily identified and removed in the spleen.

OPSI may be caused by a number of organisms, the most common being Strep. pneumonia, Haemophilus influenza, and meningococcus. For this reason, the standard of care has been to administer vaccines targeting the usual organisms to patients who have lost their spleen.

How common is OPSI? A recent paper from Gernany reviewed comprehensive data from 173 intensive care units over a 2-year period. Here are some of the more interesting factoids:

  • 2,859 ICU beds were screened, but the number of unique patients was not given. This is very disappointing because incidence cannot be calculated!
  •  52 cases of OPSI occurred
  •  Only half of the patients had received vaccines
  •  Pneumococcus was the most common bacterium (42%). There were no H. Flu or meningococcal infections.

Bottom line: Yes, OPSI exists and can occur in your asplenic patients. It is uncommon enough that you and your colleagues will probably never see a case. But proper vaccination remains important. Papers consistently show that we are collectively not very good at ensuring that our splenectomized patients receive all their vaccines, ranging from only 11-50%. We collectively need to make better efforts to provide them to our at-risk patients.

Reference: Overwhelming Postsplenectomy Infection: A Prospective Multicenter Cohort Study. Clin Infec Diseases 62:871-878, 2016.

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Inserting an NG Tube (Not an NC Tube)!

On occasion (but not routinely) trauma patients need to have their stomach decompressed. The reflex maneuver is to insert a nasogastric (NG) tube. However, this may be a dangerous procedure in some patients.

Some patients may be at risk for a cribriform plate fracture, and blindly passing a tube into their nose may result in a nasocerebral (NC) tube (see picture). Immediate and profound neurologic decompensation usually occurs. This is a neurosurgical catastrophe, and the outcome is uniformly dismal. It generally requires craniectomy to remove the tube.

The following patients are at risk:

  • Evidence of midface trauma (eyebrows to zygoma)
  • Evidence of basilar skull fracture (raccoon eyes, Battle’s sign, fluids leaking from ears or nose)
  • Coma (GCS<8)

If you really need the tube, what can you do? If the patient is comatose, it’s easy: just insert an orogastric (OG) tube. However, that is not an option in awake patients; they will continuously gag on the tube. In that case, lubricate a curved nasal trumpet and gently insert it into the nose. The curve will safely move it past the cribriform plate area. Then lubricate a smaller gastric tube and pass it through the trumpet.

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Incidental Appendectomy During Trauma Laparotomy?

The debate over incidental appendectomy has waxed and waned over the years. And for the most part, it has nearly permanently waned in general surgical cases for now. But every once in a while, I am asked about incidental appendectomy during trauma laparotomy. Is it a good idea? What reasons could there possibly be for doing it?

In the old days, we would frequently do an incidental appendectomy because… well, just because we were there. The surgeon was in the midst of a general surgical case, typically an open one, and this normal little appendix was just staring us in the face. The justification was usually, “we’ll save him another operation in the future in case he develops acute appendicitis.”

Legitimate reason? It took many years for the literature to develop, but it finally did. Here were the reasons we figured out not to do it:

  • Despite how innocuous a procedure it seems to be, there is a measurable uptick in complication rates. This is true in the usual clean contaminated general surgery cases. Some papers also noted an increased mortality when the appendectomy was added to a cholecystectomy case. In a trauma procedure with bowel injury and contamination, it’s a bit harder to see the correlation. But any time we cut or staple something out, there is always the possibility that it might break down.
  • Cost increases in laparoscopic cases if additional ports and/or equipment is needed for the appendectomy. This doesn’t really apply to major trauma cases, since we better not be doing them laparoscopically!
  • The appendix is not the useless vestigial structure we originally thought. There is evidence that it is a repository for the gut microbiome, which can help repopulate the colon with bacteria after a serious insult like prolonged antibiotic administration. Unnecessary removal may ultimately interfere with gut health and disease.

Can acute appendicitis develop after trauma laparotomy? Sure, at any time. Thankfully, it’s not very common. The presenting complaints are the same as we learned in the doctor books. However, the location of the pain and tenderness may not be in the classic location depending on the post-trauma anatomy and presence of adhesions.

Bottom line: Incidental appendectomy is no longer indicated for just about anything, including trauma laparotomy. If one of your patients presents with abdominal pain at any time, both post-traumatic and other causes must be considered. CT has become the standard for appendicitis workup, and is extremely helpful in sorting out causes in the post-op trauma patient. Use it, and if it is one of the rare cases where appendicitis is actually present, then proceed with the usual and appropriate operative on nonoperative management.

References:

  • Incidental appendicectomy with laparotomy for trauma. Br J Surg 62(6):487-9, 1975
  • Appendicitis following blunt abdominal trauma. Am J Emerg Med 35(9):1386.e5-1386, 2017.
  • Systematic review of blunt abdominal trauma as a cause of acute appendicitis. Ann R Coll Surg Engl 92(6):477-82, 2010.
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More On Lead Poisoning And Retained Bullets

Trauma professionals frequently have to leave bullets in patients. It is often more disruptive to go digging the projectiles out than to just leave them in place. But patients always want to know why and what the consequences might be.

In my last post, I discussed a very old paper on what we know about lead levels and retained bullets. Very recently, a meta-analysis was published that provides a better picture of this topic. They somehow managed to find over 2000 articles dealing with lead toxicity and bullets out there. But after someone had the pleasure of reviewing each of them, they found only 12 that had any meaningful or actionable information.

Here are the factoids:

  • All studies were observational (duh! It would be difficult to get your IRB to approve a study where patients were shot on purpose)
  • There were five cross-sectional studies, four case-control studies, and three prospective cohort studies
  • The studies were small, with a median of only 26 patients (range 15-120)
  • Eleven of the twelve studies showed an association with retained bullets and elevated blood lead levels
  • Three studies showed elevated blood levels if a fracture was present
  • The higher the number of retained fragments, the more likely lead levels were to be high
  • Higher lead levels were associated with retained fragments near a bone or joint
  • There were no good correlations with number of fragments and location vs actual lead toxicity

Bottom line: Even using meta-analysis, it is difficult to tease out meaningful answers to this question. That speaks to the low numbers of papers and their quality. However, this study does provide a little bit of guidance.

Retained bullet fragments are probably not a big worry in most patients. The bothersome cases are those where the fragments are in or near a bone or joint. And even though few patients actually developed lead toxicity, lead levels approaching 5 micrograms/dL can have physiologically significant negative effects. 

Recommendation: If your patient has a retained bullet fragment near a bone or joint, or they have “multiple” retained fragments (no good definition of this), they should have blood lead levels measured every three months for a year. If the level is rising, and certainly if it reaches the 5μ/dL level, attempts should be made to remove the fragments.

Reference: Lead toxicity from retained bullet fragments: A systematic review and meta-analysis. J Trauma 87(3):707-716, 2019.

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