All posts by The Trauma Pro

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“Medicine Is The Science Of Temporary Truths”

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Does anyone know how to write a scientific paper anymore??! My impression is that a majority of articles published in medical journals these days are seriously flawed. Yes, sometimes it’s just not possible to design or execute a study the way it really should be due to scarcity of the data or ethical issues.

But a lot of stuff I read is just not very good. Poor design. Answers to things that no one really cares about. Use of the wrong statistical analysis. And even if the basic ideas and analysis are sound, so many are just not written well.

I believe that it all comes down to poor mentoring. Designing studies and writing scientific papers is an acquired skill that requires a lot of practice. And it’s tough to learn from reading lots of other people’s papers (because they’re not very good). An experienced mentor is invaluable and can accelerate the learning curve.

My own mentors, Charles Lucas and Anna Ledgerwood, taught me by repetition. And lots of it. They told me to read a bunch of papers, then try to emulate them using my own data. I remember turning my first draft in to Dr. Lucas and getting it back a few days letter. The entire thing was covered with scribbling in red pen. Almost none of my original text remained. So I revised it and gave it back. He returned it with a fewer red marks. After many iterations, we finally had a publishable paper!

The most recent Journal of Trauma includes a very nice article on how to construct a good Discussion section in your paper. There aren’t a lot of good articles on the actual technique of medical writing (go figure). But this one is definitely worth reading and will help researchers at any level!

Reference: The anatomy of an article: The discussion section: “How does the article I read today change what I will recommend to my patients tomorrow?” J Trauma 74(6):1599-1602, 2013.

General

Contrast Blush in Children

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A contrast blush is occasionally seen on abdominal CT in patients with solid organ injury. This represents active arterial extravasation from the injured organ. In most institutions, this is grounds for call interventional radiology to evaluate and possibly embolize the problem. The image below shows a typical blush from extravasation.

Splenic contrast blush

This thinking is fairly routine and supported by the literature in adults. However, it cannot be generalized to children!

Children have more elastic tissue in their spleen and tend to do better with nonoperative management than adults. The same holds true for contrast blushes. The vast majority of children will stop bleeding on their own, despite the appearance of a large blush. In fact, if children are taken to angiography, it is commonplace for no extravasation to be seen!

Angiography introduces the risk of local complications in the femoral artery as well as more proximal ones. That, coupled with the fact that embolization is rarely needed, should keep any prudent trauma surgeon from ordering the test. It should be reserved for cases where nonoperative management is failing, but hypotension (hard fail) has not yet occurred.

The only difficult questions is “when is a child no longer a child?” Is there an age cutoff at which the spleen starts acting like an adult and keeps on bleeding? Unfortunately, we don’t know. I recommend that you use the “eyeball test”, and reserve angiography for kids with contrast extravasation who look like adults (size and body habitus).

Reference: What is the significance of contrast “blush” in pediatric blunt splenic trauma? Davies et al. J Pediatric Surg 2010 May; 45(5):916-20.

General

How To Lose A Bet And Still Win

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I recently made a bet with one of my Emergency Medicine colleagues regarding the outcome of an imaging study. The bet was that the results of the study would be negative from a trauma standpoint. The actual outcome was that the result showed a positive but clinically insignificant result.

So I lost, right? I don’t think so! How did I actually win? The bet was a monetary one ($100). The key to winning is where the money actually goes. No pizza and beer here. Most hospitals, and a few trauma programs, are associated with a charitable foundation. My pediatric trauma program is linked to one for each of the two hospitals that comprise it (Regions Hospital Foundation and Gillette Children’s Specialty Healthcare Foundation). I wrote a check to one of them, and specified the donation be earmarked for the pediatric trauma program.

Bottom line: Always be a winner! You don’t need to make bets to contribute to charitable foundations, either. Encourage your colleagues (or patients) to contribute to your hospital’s charitable foundation, and let them know that they can direct their donation to whichever program they (or you) suggest.

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Pulmonary Edema After Chest Tube Insertion

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Re-expansion pulmonary edema is an uncommon event after chest tube insertion. Typically, patients have had symptoms of pneumothorax for several days, usually 3 or more. It occurs most often if a large amount of air (or blood) is evacuated at once. The patient will typically become symptomatic within an hour, with decreased oxygen saturation and subjective breathing difficulty.

Although the mechanism is not entirely clear, it appears that the small blood vessels in the lung become more permeable if they are collapsed for an extended period. Mechanical stress from rapid re-expansion further damages the vessels, allowing them to leak. This leads to oxygenation and ventilation problems if severe. 

Practical tips:

  • Check the history. Most of these patients have had their pneumothorax for 3 or more days.
  • Check the xray. Complete pneumothorax (or large hemothorax) puts the patient at high risk.
  • Modify your chest tube insertion technique. Clamp the distal end of the tube so the pneumothorax is not evacuated suddenly as the tube goes in.
  • Modify the collection system. Do not use suction initially; only set up for water seal. Clamp the tubing on the patient side. Every 10-15 minutes release the clamp and briefly let some of the air out of the chest, then reclamp. Repeat this until all air has bubbled through the water seal chamber. 
  • Watch your patient. If they cough excessively, start to desaturate or become dyspneic, get your respiratory adjuncts. Give higher inspired oxygen by appropriate means, and consider BiPap or CPAP. In extreme cases intubation may be needed. If the patient does not have any difficulties after about an hour, connect the collection system to suction and proceed as you normally would.

Reference: Reexpansion pulmonary edema. Ann Thoracic Cardiovasc Surg 14:205-209, 2008.

General

The Poor Man’s Water Seal Test

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Placing the chest tube collection system to water seal can be a valuable tool in determining if it’s time to remove the tube. The idea is that removing suction from the system will help identify a slow air leak that may not be obvious while watching the collection system. Typically, water seal without suction is maintained for 6 hours and a chest xray is obtained to look for a new (or larger) pneumothorax.

image

Here’s a way to detect a small air leak faster. When you enter the patient room, disconnect the suction tubing from the collection system. Chat with your patient, and do your usual thorough exam. Take your time. When you are done, slowly slip the suction tubing back onto the collection system. Watch the water seal chamber closely for any bubbles that try to sneak under the partition (above).

If the fluid level slowly lowers, but no bubbles pass the partition, there is no significant leak. On occasion, I’ve seen a single bubble creep under, and this is probably okay. However, if a train of bubbles passes, an air leak is present and it is premature to consider pulling the tube. Place the system back on suction.

Like so many tests, this one is only helpful if a leak is seen. It means that a significant amount of air has accumulated in the short time you’ve been examining your patient. If there are no bubbles, there still could be a very slow leak, so they will still need a formal water seal test, if indicated. See the protocol below for details.

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