The humidified gas provided by high-flow nasal cannula is particularly important in pediatric patients because which statement is true?

• A. Smaller children expire large amounts of water when they have increased work of breathing
• B. It helps deliver oxygen molecules to narrow lower airways
• C. The larger water molecule helps carry the oxygen molecule through the alveolar-capillary membrane
• D. The larger hydrogen molecule helps the oxygen molecule engage in osmosis

Answer: (A)

Humidified, heated gas with high-flow nasal cannula is especially beneficial in children because they have higher insensible water loss from the airway surfaces due to faster breathing and smaller airways. When work of breathing increases, more water vapor is lost from the mucosa, which can dry secretions, impair mucociliary function, and worsen airflow and gas exchange. Providing humidified gas helps maintain moisture in the airways, keeps secretions thinner, and supports easier breathing and better oxygen delivery.

The other statements don’t fit the mechanism. Humidity’s benefit isn’t about carrying oxygen with larger water or hydrogen molecules, nor about osmosis driven by such molecules. Oxygen transport is not enhanced by water molecules in that way, and osmosis concerns water movement across membranes, not aiding oxygen delivery.