Abstract
Traumatic pneumothorax can progress to tension pneumothorax, which is a cause of preventable trauma death. Diagnosis must therefore be achieved without delay. Chest X-ray is performed in a supine position for the initial evaluation if patients have risk of cervical spine injuries or injuries affecting vital signs. However, nearly half of all traumatic pneumothoraces, known as occult pneumothoraces, are undetectable on supine chest X-ray. Use of ultrasonography to diagnose pneumothorax is relatively new, and diagnosis is based on the interpretation of the pleural line and underlying artifacts. The pleural line represents the parietal and visceral pleural layers in normal subjects, and corresponds to the interface between the parietal pleural layer and air in the thoracic cavity in cases of pneumothorax. Many prospective studies have recently evaluated the utility of ultrasonography to diagnose traumatic pneumothorax. These studies revealed that sensitivity ranged widely (46.5-100%), but ultrasonography was more sensitive than supine X-ray in each study, and was useful for detecting both occult pneumothorax and clinically significant cases. The negative predictive value was > 90% in all studies, meaning ultrasonography is useful for excluding traumatic pneumothorax. Further evaluations are needed to confirm whether adding ultrasonography for detecting pneumothorax in the initial trauma evaluation improves patient care or prognosis. In the future, ultrasonography during the initial trauma evaluation will evolve from focused assessment with sonography for trauma (FAST) to extended FAST (EFAST).
