Prehospital Trauma Life Support (PHTLS) Practice Test

In the case of a tension pneumothorax, vital sign changes that are indicative include decreased breath sounds on the affected side and hypotension. As air accumulates in the pleural space, it puts pressure on the lungs and the mediastinum, leading to a shift in the structures within the thoracic cavity. This results in diminished breath sounds on the side with the accumulation of air because the lung is unable to expand properly.

Hypotension occurs due to compromised venous return to the heart as the increased intrathoracic pressure interferes with cardiovascular function. The heart struggles to fill properly as the pressure constrains the vessels and decreases the effective stroke volume, thereby leading to a drop in blood pressure and potentially resulting in shock if not promptly treated.

The combination of these indicators is critical for recognizing tension pneumothorax early, which is a life-threatening condition requiring swift intervention. Other choices do not accurately represent the typical presentation of tension pneumothorax, thus confirming why this answer is most fitting.