What term should a medical assistant use to describe a patient experiencing breathing discomfort?

The term that should be used to describe a patient experiencing breathing discomfort is "dyspnea." This term specifically refers to the sensation of shortness of breath or difficulty in breathing, which perfectly captures the experience of a patient in distress due to their respiratory condition.

Other terms, while related to respiratory health, describe different conditions. "Tachypnea" refers to an increased rate of breathing, which may or may not be accompanied by discomfort. "Hypoxia" indicates a deficiency in the amount of oxygen reaching the tissues, a broader condition that may result from various underlying issues including dyspnea. "Apnea" refers to a temporary cessation of breathing, which is a different phenomenon altogether. Hence, dyspnea is the correct term for the specific experience of breathing discomfort.