Which of the following gases is primarily utilized for respiratory support in oxygen therapy?

Oxygen is the gas primarily utilized for respiratory support in oxygen therapy because it is essential for human respiration. It is the critical component that the body needs for cellular metabolism, which produces energy to fuel all bodily functions. In therapy, oxygen is delivered to patients who are unable to take in sufficient amounts through normal breathing due to various medical conditions like chronic obstructive pulmonary disease (COPD), pneumonia, or during recovery from surgery.

While other gases like nitrous oxide and ethylene are used in specific medical applications—such as anesthesia—their roles are entirely different from that of oxygen in respiratory support. Carbon monoxide is a toxic gas that binds to hemoglobin more effectively than oxygen, preventing oxygen transport in the bloodstream, leading to harmful effects. Therefore, the use of oxygen in therapy is vital for enhancing oxygenation and improving patient outcomes in respiratory distress situations.