A nasal cannula is a medical device to provide supplemental oxygen therapy to people who have lower oxygen levels. There are two types of nasal cannulas: low flow and high flow.
The device has two prongs and sits below the nose. The two prongs deliver oxygen directly into your nostrils.
High Flow Oxygen vs. Low Flow Oxygen
HFNC is the medical abbreviation for a high-flow nasal cannula. These devices blow humidified, heated oxygen into the nostrils. They can deliver up to 60 liters of oxygen per minute.
Low flow nasal cannulas can only deliver a nasal cannula flow rate of 4-6 liters of oxygen per minute. They don't provide humidified or heated oxygen. So, they often dry out the nasal passages. This can lead to bleeding or irritation.
Nasal Cannula Uses
Your doctor may recommend a nasal cannula if you are having trouble breathing or if you do not have enough oxygen in your blood. Reasons you might use a nasal cannula include:
Nasal Cannula Risks
The risks of using a nasal cannula include:
Abdominal distension. Children or people undergoing anesthesia are at particular risk of abdominal distension, or bloating of the stomach. Other devices that deliver oxygen maintain a higher level of positive airway pressure and carry no risk of distension. However, HFNCs have lower positive airway pressure which can allow some gas to get into the digestive system, causing abdominal bloating.
Nasal injury or irritation. This is more common with low flow nasal cannulas, but can also occur with high flow systems.
Pneumothorax (collapsed lung). There is a small risk of developing a collapsed lung during treatment with a HFNC. In one study, two children, 1% of the children in the study, who received supplemental oxygen via a nasal cannula developed a pneumothorax.
Nasal Cannulas and COVID-19
In the earliest days of the COVID-19 pandemic, people with severe cases were intubated. During this procedure, doctors put a tube down a patient's throat, allowing a mechanical device to breath for the patient.
There are a lot of side effects to intubation, especially long-term intubation. Complications can include difficulty speaking and swallowing after doctors remove the tube.
Studies show success in treating people who have COVID-19 with high flow nasal cannulas before intubation. One study from early in the pandemic in a Chicago hospital emergency room showed that treating people with a HFNC for 10 days can reduce the need for intubation.
Another study from France shows a lower mortality rate and a lower intubation rate in people with COVID-19 who are treated with a HFNC within 24 hours of being admitted to the intensive care unit (ICU).
Using a Nasal Cannula at Home
While nasal cannulas are used to provide supplemental oxygen in ICUs and hospital wards, people with certain conditions like COPD or pulmonary fibrosis may use one at home.
While setting up your home oxygen supply, make sure you understand any maintenance requirements. There are a few different devices you may use.
Oxygen concentrator. An oxygen concentrator delivers a supply of concentrated oxygen, drawn from the air around you, through your cannula. Oxygen concentrators come in two types: large stationary ones that remain in your home and smaller portable ones for use outside the home. One benefit to a portable oxygen concentrator is that you can bring it on an airplane.
Oxygen tank. These tanks hold either liquid oxygen or compressed gas. You cannot bring these devices on an airplane.
Oxygen conserving device. If you use a compressed gas oxygen tank, you will need one of these devices to regulate the flow of oxygen.
Change the long tube that connects your cannula to the oxygen device at least every other month, if not more often. Change your nasal cannula once a week or more often if it gets dirty. Even if it is not time to change the tubing or cannula, keep extra at home in case the equipment gets damaged.
Have a backup plan in case of a power outage. Some people with an oxygen concentrator system use oxygen tanks as a backup method in case of power failure. Others use a generator.
Fire safety is very important when using supplemental oxygen at home. Keep your oxygen equipment away from open flames. Oxygen is highly flammable and could cause a fire to spread faster than usual.