Which symptom is associated with a tension pneumothorax?

A tension pneumothorax occurs when air becomes trapped in the pleural space and creates increasing pressure that collapses the lung on the affected side. The presence of absent breath sounds on the affected side is a critical indication of this condition. When the lung is collapsed, there is no air movement in that area, which means that no breath sounds can be detected upon auscultation. This absence of breath sounds is a significant clinical finding and may prompt immediate intervention, as tension pneumothorax can rapidly lead to respiratory and circulatory failure.

In contrast, the other symptoms listed are not characteristic of a tension pneumothorax. For example, decreased heart rate is typically not observed; rather, the heart rate may increase due to the body's stress response and compensatory mechanisms. Excessive coughing is more associated with conditions that irritate or inflame the lungs and airways rather than a tension pneumothorax, which primarily affects air movement rather than provoking significant cough reflex. Clear lung sounds upon auscultation would indicate that the lung is functioning normally on that side, which contrasts with the expected findings in a tension pneumothorax where breath sounds would be absent due to the collapse of the lung.