What vital sign is crucial to monitor in suspected tension pneumothorax?

Monitoring oxygen saturation is crucial in suspected tension pneumothorax because this condition leads to impaired gas exchange and respiratory function. As air accumulates in the pleural space, it puts pressure on the lung and can collapse it, which significantly reduces oxygen transfer to the bloodstream. Therefore, a drop in oxygen saturation is a key indicator of respiratory distress and hypoxia associated with tension pneumothorax.

In this scenario, heart rate, blood pressure, and temperature may offer additional information about a patient's overall condition, but they are not as directly indicative of the respiratory compromise caused by tension pneumothorax. Oxygen saturation specifically assesses the effectiveness of respiration and the adequacy of oxygen delivery to tissues, making it the most pertinent vital sign to monitor in this critical situation.