A nasal cannula is a lightweight, flexible tube that delivers supplemental oxygen directly into your nostrils. It’s the most common oxygen delivery device used in hospitals, clinics, and home settings. The tube hooks around your ears, runs along your cheeks, and has two short prongs that sit just inside your nose, while the other end connects to an oxygen source like a concentrator or wall outlet.
How a Nasal Cannula Works
The two small prongs release a steady stream of oxygen into the space at the back of your nose and throat. When you breathe in, that oxygen mixes with regular room air before reaching your lungs. Room air is about 21% oxygen. A standard nasal cannula can raise that concentration to roughly 24% to 44%, depending on the flow rate your provider sets.
The general rule: each additional liter per minute of flow adds about 4% more oxygen to what you breathe in. So at 1 liter per minute, you’re getting around 24% oxygen. At 2 liters, roughly 28%. At the maximum standard setting of 6 liters per minute, you reach approximately 44%. This makes the nasal cannula well suited for people who need a modest oxygen boost rather than high concentrations.
Because the device is a “low-flow” system, it delivers oxygen at rates well below the speed of a normal breath (which pulls in air at roughly 30 liters per minute). The gap gets filled by room air, which is why the actual oxygen percentage varies with how deeply and quickly you breathe.
Standard vs. High-Flow Nasal Cannulas
The standard nasal cannula tops out at about 6 liters per minute. For people who need significantly more oxygen support, there’s a high-flow version that can push heated, humidified oxygen at rates up to 60 liters per minute. High-flow nasal cannulas use wider prongs and specialized equipment, and they’re typically found in hospital settings rather than at home.
High-flow systems offer several advantages over both standard cannulas and face masks. They deliver a more precise and reliable oxygen concentration, help clear mucus from the airways, reduce the effort of breathing, and are generally more comfortable than a tight-fitting mask. The warming and humidification prevent the severe nasal drying that would occur if cool, dry oxygen were blasted into the nose at those rates. These devices are commonly used for acute respiratory failure and other situations where conventional oxygen therapy falls short.
Why It’s Preferred Over a Face Mask
For many patients, a nasal cannula is more practical than an oxygen mask. It leaves your mouth completely free, so you can talk, eat, drink, and take medications without removing your oxygen supply. It’s lighter, less claustrophobic, and easy to forget you’re wearing it once you adjust to the feel of the prongs. For people on long-term home oxygen, that comfort makes a real difference in daily life.
The tradeoff is oxygen capacity. A simple face mask can deliver higher concentrations than a standard cannula, and specialized masks with reservoir bags can push oxygen levels even higher. If your needs exceed what 6 liters per minute can provide, your care team will typically switch you to a mask or a high-flow system.
Common Side Effects
Nasal cannulas are safe, but wearing one for hours or days at a time can cause a few minor problems. The most common is dryness and irritation inside the nose, which can lead to nosebleeds in some people. A simple saline nasal spray usually handles this. At higher flow rates (generally above 4 liters per minute for older children and adults), your provider may add a humidifier bottle to the oxygen line to moisten the air before it reaches your nose.
The tubing that loops behind your ears can also rub the skin raw over time. Tucking a small piece of gauze or soft foam between the tube and your skin prevents this. Your lips and the skin around your nose may also get dry or irritated, especially in low-humidity environments.
Keeping Your Cannula Clean
If you use a nasal cannula at home, basic hygiene keeps it functioning well and reduces infection risk. Wash the prongs with liquid soap and rinse them thoroughly once or twice a week. Replace the entire cannula every two weeks. If you catch a cold or other respiratory infection, swap in a fresh cannula once your symptoms clear rather than waiting for the two-week mark.
What to Expect When Using One
Wearing a nasal cannula feels odd at first. The prongs create a slight tickle or pressure inside your nostrils, and the tubing across your face takes some getting used to. Most people stop noticing it within a day or two. You can sleep with it on, and many home oxygen users do exactly that, sometimes using oxygen only at night or during physical activity depending on their needs.
The cannula connects to your oxygen source through several feet of flexible tubing, giving you room to move around your home. Portable oxygen concentrators and small compressed-gas tanks let you take the setup outside the house as well. The key is making sure the prongs stay seated in your nostrils and the tubing doesn’t kink, since either problem means you’re not getting the oxygen flow you need.
Nasal cannulas come in different sizes for infants, children, and adults, with prong widths matched to nostril size. A properly fitted cannula should feel snug but not painful, and the prongs should sit just inside the nostrils without pressing deep into the nasal passages.