The combination of absent breath sounds on the left, tracheal deviation to the right, and hypotension in a trauma patient strongly indicates a tension pneumothorax. This occurs due to air accumulating under pressure in the pleural space, causing lung collapse and mediastinal shift, which compresses the heart and major vessels leading to hypotension. The immediate life-saving intervention is needle decompression to relieve the pressure, followed by chest tube insertion. Delay in decompression can quickly result in cardiovascular collapse and death. Therefore, prompt recognition and emergency needle thoracostomy are critical.

Reference: Tintinalli's Emergency Medicine: A Comprehensive Study Guide, Judith E. Tintinalli, 9th Edition.