All posts by TheTraumaPro

Pop Quiz – Final Answer!

So what was wrong with that post-chest tube x-ray taken after placement for treatment of a pneumothorax?

The answer? The chest tube is not in the chest!

But wait, you say. That x-ray looks totally normal. The placement couldn’t be more perfect!

Remember, an x-ray image is a 2D representation of a 3D object. You can easily see the location of the tube in the x and y axes, and it looks great. But the z (depth) axis? You have no clue. And in this case, the tube is along the posterior chest, under the scapula. That’s a potential reason for the persistent pneumothorax.

Some readers commented that the tube could be in the lung parenchyma or a fissure. Fissure placement does occur occasionally, and may hamper the function of the tube somewhat, but it will still work. My radiology colleagues occasionally call me to warn that the tube goes through the lung parenchyma. Fortunately for the patients, this is almost never true. Just an illusion seen on the CT. It is very difficult to place a tube through normal lung. The resistance is substantial enough to make any reasonable person stop pushing. Hopefully.

Bottom line: Remember that a plain x-ray is only two dimensional. Your brain will place the objects seen on it wherever you desire. But you do not know how deep or superficial any object is without additional information. Even CT scans simulate 3D by stacking a bunch of this slices or shaded images to fool your brain. When placing a chest tube, verify its insertion point with your finger; you can follow the tube down to the chest wall and feel it vanish between the ribs. Don’t just assume you know where it’s going.

Hat tips to @CookCountyTraum, HollyT and Josh for getting it correct!

Pop Quiz! Hint Hint!

Yesterday I hit you with a chest x-ray after chest tube insertion in a young man who presented with a pneumothorax. The lung was not yet expanded (chest x-ray taken less than 5 minutes after the procedure).

So what’s wrong? I had a lot of good guesses yesterday (@ResusReview, @uclamutt, and others in the comments to name a few), but nobody quite got it. Yes, the lung is not up yet. No, the tube is not in a fissure. The person inserting the tube worked up a sweat doing it, taking about 10 minutes to get it in. But some air came out initially, and the tube rotated freely on its axis.

Any ideas? Tweet or comment! Answer tomorrow.

Pop Quiz! What’s Wrong In This Picture?

Here’s another one to challenge your skills! A young male presents to your ED after minor chest trauma with pleuritic chest pain and slight shortness of breath. A chest x-ray is obtained which shows a large pneumothorax on the right. You insert a chest tube, and the procedure goes well.

Another x-ray taken immediately after insertion looks like this:

The lung is not yet fully expanded, but the patient already feels better. 

What is wrong in this picture? Tweet or leave comments. Hints tomorrow if I don’t receive the correct answer.

But The Radiologist Made Me Do It!

The radiologist made me order that (unnecessary) test! I’ve heard this excuse many, many times. Do these phrases look familiar?

  1. … recommend clinical correlation
  2. … correlation with CT may be of value
  3. … recommend delayed CT imaging through the area
  4. … may represent thymus vs thoracic aortic injury (in a 2 year old who fell down stairs)
Some trauma professionals will read the radiology report and then immediately order more xrays. Others will critically look at the report, the patient’s clinical status and mechanism of injury, and then decide they are not necessary. I am firmly in the latter camp.
But why do some just follow the rad’s suggestions? I believe there are two major camps:
  • Those that are afraid of being sued if they don’t do everything suggested, because they’ve done everything and shouldn’t miss the diagnosis
  • Those that don’t completely understand what is known about trauma mechanisms and injury and think the radiologist does
Bottom line: The radiologist is your consultant. While they are good at reading images, they do not know the nuances of trauma. Plus, they didn’t get to see the patient so they don’t have the full context for their read. First, talk to the rad so they know what happened to the patient and what you are looking for. Then critically look at their read. If the mechanism doesn’t support the diagnosis, or they are requesting unusual or unneeded studies, don’t get them! Just document your rationale clearly in the record. This provides best patient care, and minimizes the potential complications (and radiation exposure) from unnecessary tests.
Related post: 

Reference: Pitfalls of the vague radiology report. AJR 174(6):1511-1518, 2000.

Liver Laceration And Liver Function Tests

Over the years I’ve seen a number of trauma professionals, both surgeons and emergency physicians, order liver transaminases (SGOT, SGPT) and bilirubin in patients with liver laceration. I’ve never been clear on why, so I decided to check it out. As it turns out, this is another one of those “old habits die hard” phenomena.

Liver lacerations, by definition, are disruptions of the liver parenchyma. Liver tissue and bile ducts of various size are both injured. Is it reasonable to expect that liver function tests would be elevated? A review of the literature follows the typical pattern. Old studies with very few patients.

From personal hands-on observations, the liver tissue itself tears easily, but the ducts are a lot tougher. It is fairly common to see small, intact ducts bridging small tears in the substance of the liver. However, larger injuries can certainly disrupt major ducts, leading to major problems. But I’ve never seen obstructive problems develop from this injury.

A number of papers (very small, retrospective series) have shown that transaminases can rise with liver laceration. However, they do not rise reliably enough to be a good predictor of either having an injury, or the degree of injury. Similarly, bilirubin can be elevated, but usually not as a direct result of the injury. The most common causes are breakdown of transfused or extravasated blood, or from critical care issues like sepsis, infection, and shock.

Bottom line: Don’t bother to get liver function tests in patients with known or suspected injury. Only a CT scan can help you find and/or grade the injury. And never blame an elevated bilirubin on the injury. Start searching for other causes, because they will end up being much more clinically significant.

References:

  • Evaluation of liver function tests in screening for intra-abdominal injuries. Ann Emerg Med 20(8):838-841, 1991.
  • Markers for occult liver injury in cases of physical abuse in children. Pediatrics 89(2):274-278.
  • Combination of white blood cell count with liver enzymes in the diagnosis of blunt liver laceration. Am J Emerg Med 28(9):1024-1029, 2010.