I’ve always assumed scanning the chest at the level of the nipples would be best for finding a pneumothorax. Recently, I had a trauma patient where I excluded pneumothorax after a negative ultrasound scan. The CXR was negative as well. But the CT showed a rather big right sided pneumothorax that I hadn’t spotted with US. A recent article in Journal of American Emergency Medicine shows we probably need to scan lower to catch the most pneumos.

The study
What’s the best area to scan for a pneumo? Do you need to scan several, or even all areas of the chest? This was a retrospective convenience sample of CT’s of 183 trauma patients with pneumothorax. The chest was divided into 13 zones shown in the image below. They looked for the zones affected by the pneumothorax and the zone for the largest anterior-posterior diameter.

The results
There was increasing frequency of pneumothoraces from lateral to medial, and from apical to basal aspects of the lungs. The zones most frequently affected by pneumothorax in this study were 9, 11 and 12, the most anterior and basal zones.

Scan basally
Only larger pneumos need treatment and placement of a chest tube. According to this study, larger pneumos will also affect the more apical zones that I usually scan. But for the highest sensitivity, you need to scan the anterior, but most basal lung aspects. Time to change.

Anatomical distribution of traumatic pneumothoraces on chest computed tomography: implications for ultrasound screening in the ED, Am J Emerg Med. 2012.

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  1. Minh Le Cong says:

    thanks Thomas. great pickup! I have forwarded this onto my retrieval colleagues in my service. v important stuff.
    keep up the great FOAMEd work, mate. One day need to record your wisdom for PHARM podcast. Love to have you as a regular podcast contributor!

    • Thomas D says:

      Thanks for your support, Mihn! And likewise! I’ve learned a lot from your contributions online! It’s fantastic to have all these resources pointing me to important updates in my field FOAMed is a whole new – and better – way of learning. We’ll certainly talk about the podcast sometime!

  2. toby says:

    Nice post. I have a very simple approach – air rises to the highest point. Thus, given that chests come in a range of shapes and sizes, I look from the side, find the highest point of the chest and scan there. The other thing that seems to help is to adjust the depth on the screen so that the pleural line is in the middle of the screen – I think this helps when you use M mode.

  3. Thomas D says:

    Hi, Toby, I agree, you should scan at the highest point. And I thought I did that – but I was too apical. So this article set me straight, and I guess looking from the side should fix that for future scans. Thanks for your tips!

  4. Shata Hari says:

    Thanks thomas.very good post.

  5. Pingback: Lungultraljud | Akutsjukvård

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