Oxygen that is entirely devoid of moisture will:

• A. Will improve mucous membranes
• B. Dry the patient's mucous membranes quickly
• C. Increase humidity
• D. Have no effect on mucous membranes

Answer: (B)

Dry, moisture-free oxygen will pull moisture from mucous membranes as it flows across them. Because the gas lacks water vapor, the airways lose humidity quickly, drying the mucosa and leading to irritation, crusting, and thicker secretions. That’s why the most accurate outcome is that dry oxygen will dry the mucous membranes quickly. It wouldn’t improve or increase humidity; instead it reduces humidity. In clinical practice, humidification is often used with oxygen therapy to protect the mucosa and keep airways comfortable during extended use.