Disaster Averted: Ultrasound and Pneumothorax by Drs. Mailhot , Perera and Mandavia

You’re looking after a patient who was a front-seat passenger in a motor vehicle collision.  The primary and secondary surveys are completely normal, but because of the mechanism of injury, you order some basic X-rays.  Here is the patient’s chest X-ray: 

The radiologist reads “Left-sided Pneumothorax”, and is even so thoughtful as to include the helpful arrow seen in the image, pointing out the pneumothorax for all to see. 

You ask the nurse to get a chest-tube kit ready, as you debate the merits of a chest tube versus a Heimlich valve, or maybe just watchful waiting and high-flow oxygen.  Either way, this patient is headed for an admission… 

Something bothered you about the radiologist’s read, though, and you decide to see if you can detect the pneumothorax with ultrasound.  After all, a chest X-ray can have both false negatives and false positives for pneumothorax.  Scanning between the ribs on the anterior chest, you get your answer. 

This ultrasound clip shows normal lung.  That shimmering horizontal white line you see moving left and right is the pleural line (parietal + visceral pleura), sliding back and forth as the patient breathes in and out.  This is known as “lung sliding”.  Your patient has this finding, suggesting that a pneumothorax is NOT present. 

This clip, obtained from a different patient, shows a pneumothorax.  Again, you can see a horizontal white line in the foreground, but this time no shimmering, to-and-fro movement of this line is seen.  There is no lung sliding, implying that the patient has a pneumothorax. 

You decide to repeat X-rays to confirm your suspicions, and sure enough, the repeat chest X-ray is read as normal.  The ‘pneumothorax’ turns out to be a skin fold, an infrequent but important cause of false positive pneumothorax on chest X-ray. 

Using ultrasound can allow you to confirm or refute suspicious findings seen on plain radiography.  In this case, ultrasound spared the patient a painful, morbid (and ultimately unnecessary) procedure, a hospitalization, and an expensive bill. 

Click here for more about how to use ultrasound to detect pneumothorax. 

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