Written by Chris Thom
Spoon Feed
In high severity trauma patients, the sensitivity and specificity of POCUS for pneumothorax was 68% and 100%, respectively, for all operators.
Experience is key
This was a retrospective study of severely injured trauma patients presenting to a single level-1 trauma center ED from 2019 to 2022. Findings from FAST exams performed in the trauma bay were retrospectively reviewed to assess accuracy in cases of clinically significant pneumothorax. This was defined as pneumothorax requiring a chest tube within 2.5 hours after ED arrival. The gold standard for presence of pneumothorax was “rush of air” after chest tube placement or pneumothorax visualized on CT for those patients who received this prior to chest tube.
Of 924 patients, 40 had a clinically significant pneumothorax, with POCUS demonstrating a sensitivity of 68% (95%CI 52-80) and specificity of 100% (95%CI 84-100). Secondary review of these 40 patients by ED physicians with ultrasound fellowship training resulted in a sensitivity of 84% (95%CI 70-93) and specificity of 100%.
How will this change my practice?
One of the central tenets of POCUS practice is that the test characteristics of a given application depend on the operators involved. More experienced operators tend to have higher overall accuracy, and POCUS becomes a much more useful test in their hands. Time and time again, we see that the POCUS pneumothorax examination is particularly subject to wide swings in accuracy depending on the operators involved. If you use a heterogeneous group of operators with minimal dedicated POCUS training, you end up with sensitivities that are similar or only slightly improved from x-ray. However, among operators with significant ultrasound training, the test becomes clearly superior to chest x-ray. This distinction is critically important to understand when exploring this topic and reminds us that we need robust and recurring POCUS training for all physicians who work in the trauma bay.
POCUS Pro-Tips and Clips
To rule out pneumothorax, we want to visualize the visceral and parietal pleura sliding against each other. This will appear as a “shimmering” movement, with associated comet tails from the pleural line. The highest yield location is along the anterior chest wall, where one can quickly move up and down to image two or three intercostal spaces on each side with ease. The linear probe provides better clarity, but a low-frequency probe is adequate if the operator clearly sees “yes” or “no” pneumothorax on imaging.
Source
Emergency Department Accuracy of Point-of-Care Ultrasound in Identifying Clinically Significant Pneumothorax in High-Severity Trauma Patients. J Emerg Med. 2025 Oct;77:140-151. doi: 10.1016/j.jemermed.2025.07.009. Epub 2025 Jul 17. PMID: 40913875.
