Which of the following is NOT a sign of a tension pneumothorax?

In the context of tension pneumothorax, the correct answer centers on the physiological changes and signs typically presented in patients with this condition. A tension pneumothorax occurs when air enters the pleural space and cannot escape, leading to increased pressure that compresses the lung and shifts mediastinal structures, including the trachea.

Deviated trachea is a classic sign of tension pneumothorax, as the increased pressure pushes the mediastinum away from the affected side. Respiratory distress is also a common symptom since the lung on the affected side is compromised, making it difficult for the patient to breathe adequately. Decreased breath sounds on one side occur because the air in the pleural space prevents normal ventilation of the lung in that area.

Increased heart rate, while it can be a response to various conditions, is not a specific sign of tension pneumothorax. Instead, it may occur due to other reasons, such as anxiety or compensatory mechanisms secondary to oxygen deprivation. Thus, it is not as definitive a sign as the other options presented.