Green tubing that is slightly stiffer and heavier than standard nasal cannula is associated with which device?

• A. Standard Nasal Cannula
• B. Venturi Mask
• C. Non-Rebreather Mask
• D. High Flow Nasal Cannula

Answer: (D)

High flow nasal cannula systems are designed to deliver heated, humidified gas at very high flow rates, up to about 60 L/min in adults. To push that much gas through the nose reliably, the tubing is thicker, stiffer, and heavier than standard cannula tubing. The green, more rigid tubing is a practical cue that this setup is meant for high-flow delivery rather than simple low-flow oxygen. This design supports not only the high flow but also the heating and humidification that improve airway moisture, reduce nasopharyngeal dead space, and can generate a small amount of positive airway pressure. In contrast, a standard nasal cannula uses a soft, thin tube for low-flow delivery, a Venturi mask uses a mask and jet-entrainment system with lightweight tubing, and a non-rebreather mask relies on a tight mask and reservoir bag without the high-flow, heated humidification features.