Which gas is used alongside nitrogen to create medical air?

Medical air is a specially processed mixture of gases that is primarily intended for respiratory use. The correct gas used alongside nitrogen to create medical air is oxygen. Medical air typically consists of approximately 21% oxygen and 78% nitrogen, with trace amounts of other gases. This blend is designed to be safe and effective for patient use in various medical settings.

Using oxygen in the mixture ensures that the air supplied is breathable and meets the necessary quality standards defined for medical applications. The inclusion of nitrogen helps to balance the proportions and maintain a composition similar to atmospheric air, while keeping the oxygen levels adequate for respiratory support.

The other gases listed do not serve this purpose effectively. Carbon dioxide is not suitable for creating breathable air, as it can lead to respiratory acidosis if inhaled in significant amounts. Ethylene is a flammable gas primarily used in the production of plastics and is not suitable for respiratory applications. Helium, while sometimes used in specific medical conditions to reduce airway resistance, does not form a part of medical air and does not provide the necessary oxygen levels for breathing.

Thus, oxygen USP is the key component that, when paired with nitrogen, results in the medical air essential for patient care.