Which of these gases is NOT commonly used in medical gas therapy?

Argon is not commonly used in medical gas therapy. Medical gases serve specific therapeutic purposes, with common gases including oxygen, nitrous oxide, and helium, each fulfilling distinct roles in patient care.

Oxygen is a crucial gas used to treat hypoxemia and support respiration in patients with various conditions. Nitrous oxide is often utilized as an anesthetic and analgesic, particularly in dental procedures and during labor for pain management. Helium is sometimes utilized in combination with oxygen to treat conditions such as severe asthma or COPD due to its low density, which helps improve airflow.

In contrast, argon is primarily an inert gas and is not suitable for therapeutic interventions in the same way that the other gases are. Its role in medical practice is limited, making it uncommon in the context of medical gas therapy.