Combat Medic-Performed Auscultation Versus Thoracic Ultrasound Image Interpretation for Pneumothorax Detection: Look or Listen?

Background Pneumothorax (PTX) is a potentially life-threatening condition encountered by U.S. Army combat medics on the battlefield. PTX, when left untreated, can progress to tension PTX, a leading cause of preventable death on the battlefield which can be difficult to diagnose based on physical exam alone due to variable physical exam findings. Prior literature shows medics can accurately use point-of-care ultrasound (POCUS) to diagnose PTX in cadaver and porcine models; however, no studies have directly compared the diagnostic accuracy of ultrasound (US) and physical exams performed by this population. We sought to compare medic diagnostic accuracy of a simulated PTX using these two diagnostic modalities. Methodology We conducted a prospective, observational study in which medics from the Flight Paramedic Program at Joint Base San Antonio-Sam Houston, TX received a standardized 30-minute training on physical exam and US diagnosis of PTX, followed by a 20-minute hands-on US familiarization session. Participants were then randomly selected into cohorts to evaluate 12 high-fidelity manikin lung fields and 12 thoracic US video clips for the presence of PTX in a simulated combat environment. Cohorts evaluated the same manikins and thoracic US video clips but in opposing sequences. Our primary outcome compared the sensitivity and specificity of PTX identification via thoracic US image interpretation and physical exam. Results In total, 21 medics evaluated 252 hemithoraces and interpreted 252 thoracic US images. We found a statistically significant difference favoring medics' sensitivity with US image interpretation over physical exam to detect PTX (85.7% vs. 72.4%, p = 0.004). There was no statistically significant difference in specificity between these modalities (81.9% vs. 69.4%, p = 0.139). Conclusions After brief training, medics demonstrated greater sensitivity to detect PTX using thoracic US image interpretation compared to physical exam in a simulated combat environment. Further studies involving medics' ultrasound image acquisition capability in human patients in austere combat environments are warranted.