an occlusive dressing at the wound site This is best done when the patient is in full expiration A chest tube should be placed immediately to prevent development of a tension pneumothorax The chest tube should be inserted at a site different than the open wound Larger open chest wounds may need surgical closure Diagnostic Testing Chest Radiograph A CXR remains the most widely used test for the diagnosis of hemothorax and pneumothorax Both conditions are better visualized in the upright position than supine Plain radiographic signs of a pneumothorax may include identification of the pleural line, a hyperlucent hemithorax, pleural air at the lung base, and/or an unusually well-defined heart and mediastinal outline due to pleural air rising anteriorly A tension pneumothorax is indicated by the presence of midline shift to the contralateral side of the pneumothorax ( Fig 115.3 ) Smaller pneumothoraces may be better visualized by positioning the patient in the lateral decubitus position with the concerning side up Expiratory CXRs not add significantly to the evaluation Hemothorax on CXR may appear as blunting of the costophrenic angle, haziness or opacification of the hemithorax, or a visible air–fluid level Bedside Ultrasound Bedside US has become part of the standard assessment of trauma patients due to its ability to rapidly detect injuries and inform management strategies The major finding of pneumothorax is absence of lung sliding, while hemothorax is determined by the presence of fluid in the pleural space Studies in adults have shown the extended focused assessment with sonography for trauma (E-FAST) examination to be more sensitive in the detection of pneumothorax than supine radiographs with a sensitivity between 50% and 80% and specificity of 95% to 100% when compared to chest CT In the multiply injured or unstable patient, US may be particularly valuable in prioritizing further evaluation and interventions, particularly in adult patients