Which device delivers supplemental oxygen through the nostrils?

• A. MDI
• B. Nasal Cannula
• C. NRB
• D. Nebulizer

Answer: (B)

Delivering supplemental oxygen through the nostrils is achieved with a nasal cannula. This device has two small prongs that sit inside the nostrils and a soft tube that runs behind the ears to an oxygen source. Oxygen flows through the tubing and out the prongs into the nasal passages, allowing the patient to breathe normally while receiving oxygen. Flow rates are commonly 1–6 L/min, with higher flows delivering higher FiO2 (roughly up to around 40–50% in typical practice). The nasal cannula is comfortable for long-term use and allows talking and eating.

The other devices serve different purposes: a metered-dose inhaler delivers aerosolized medications, not oxygen; a non-rebreather mask covers the nose and mouth to provide a high concentration of oxygen but does not deliver through the nostrils; a nebulizer creates a mist of medication to inhale, usually via a mask or mouthpiece.