Which of the following is an early sign of tension pneumothorax?

Severe respiratory distress is recognized as an early sign of tension pneumothorax because this condition occurs when air enters the pleural space and is unable to escape, leading to increased pressure within the thoracic cavity. This pressure buildup can collapse the lung on the affected side and compress the great vessels, severely impairing oxygenation and ventilation.

Patients experiencing tension pneumothorax will often exhibit signs of respiratory distress, such as rapid, labored breathing, use of accessory muscles, and significant difficulty breathing. This contrasts with a stable blood pressure, which may not be present in the early stages of tension pneumothorax as the condition can rapidly progress to hemodynamic instability. Additionally, normal breath sounds on both sides would not be expected because the affected lung may not be ventilating adequately. A high oxygen saturation level above 90% is also unlikely in cases of tension pneumothorax due to poor oxygenation resulting from compromised lung function. Thus, severe respiratory distress is a hallmark early indicator of this critical condition.