What to Know About Non-Rebreather Masks

Medically Reviewed by Dan Brennan, MD on May 01, 2021

A non-rebreather mask is a special medical device that helps provide you with oxygen in emergencies. These masks help people who can still breathe on their own but need a lot of extra oxygen. 

Non-rebreather masks are used to treat several conditions. Here’s what you need to know about how they can affect your health.

A non-rebreather mask involves four important parts:

  • ‌The mask
  • ‌A reservoir bag
  • ‌2 to 3 one-way valves
  • ‌Tubes to connect the reservoir bag to an oxygen tank

‌Oxygen flows from the tank into the reservoir bag. A one-way valve connects the reservoir bag to the mask. When a person breathes in, oxygen moves from the bag into the mask.

One-way valves. When someone exhales, the first one-way valve prevents their breath from returning to the reservoir bag. Instead, the exhale pushes air through one or two additional one-way valves on the outside of the mask. These valves also prevent the person from breathing in air from the rest of the room.

FIO2. Non-rebreather masks are designed to deliver a lot of extra oxygen to your airway. The normal fraction of inspired oxygen (FIO2), or concentration of oxygen in the air, in any room is about 21%.

Non-rebreather masks provide you with 60% to 91% FIO2. To do this, they form a seal around your nose and mouth. This seal in combination with the one-way valves guarantees you only breathe the gas from the oxygen tank.

There are many ways to resolve breathing problems that are more convenient than non-rebreather masks. Non-rebreather masks are usually reserved for emergency situations when you need a lot of oxygen at once. Some of these emergencies include the following.

Traumatic injuries. Any serious injury to your chest or lungs may make it difficult for you to get enough oxygen. A non-rebreather mask can help keep you breathing while emergency actions are taken to stabilize your lungs.

Smoke inhalation. Breathing in smoke can seriously damage your lungs. One effect of smoke inhalation is swelling and inflammation of your airways. A non-rebreather mask helps provide enough oxygen to keep you breathing until the inflammation goes away.

Carbon monoxide poisoning. One of the effects of carbon monoxide poisoning is a lower blood capacity for oxygen. Using a non-rebreather mask with high-flow oxygen can help your body recover its normal capacity for oxygen more quickly.

Cluster headaches.A cluster headache is an extremely painful condition that makes it difficult to function on a daily basis. Studies have shown that high-flow oxygen through a non-rebreather mask is one of the most immediate and effective treatments for resolving cluster headaches.

Chronic airway limitations. In rare cases, a non-rebreather mask may be used to help people with chronic airway limitations. A non-rebreather mask can help you recover if you have trouble getting enough oxygen regularly due to an ongoing medical condition.

Non-rebreather masks aren’t perfect. They are the best way to provide you with high-flow oxygen quickly but they have a significant flaw. 

Suffocation. Non-rebreather masks form a seal around your nose and mouth. You can only breathe while the mask is hooked up to an oxygen tank‌. You can’t get more air if the oxygen tank runs out. Anyone using a non-rebreather mask should be supervised in case the oxygen tank empties to make sure they don’t suffocate.

There are several other options for oxygen therapy. People who don’t need all the oxygen a non-rebreather mask provides can use other forms of oxygen delivery that don’t have the same risks. These include the following.

Nasal cannulas. A nasal cannula is a tube that runs into your nose. It delivers a small amount of oxygen consistently for a long period of time. Some people will use a nasal cannula for months or years if they have lung damage or COPD.

Simple oxygen masks. Like nasal cannulas, a simple face mask provides a small amount of extra oxygen. These masks can be worn when a nasal cannula isn’t working or isn’t practical, like while you’re trying to sleep. They are also more common for children who don’t like the feeling of tubes in their nose.

Partial rebreather masks. Partial rebreathers allow some air to be recycled instead of completely preventing you from rebreathing air. They look very similar to non-rebreather masks, but they use two-way instead of one-way valves. Partial rebreather masks provide very high concentrations of oxygen without the risk of suffocation.

Show Sources


BMJ Open Respiratory Research: “Guideline for oxygen use in adults in healthcare and emergency settings.”

‌‌Chest: “Prolonged airway and systemic inflammatory reactions after smoke inhalation.”

Clinical toxicology: “Treatment of carbon monoxide poisoning: high-flow nasal cannula versus non-rebreather face mask."

International Journal of Chronic Obstructive Pulmonary Disease: “Occupational exposure to vapor, gas, dust, or fumes and chronic airflow limitation, COPD, and emphysema: the Swedish CArdioPulmonary BioImage Study (SCAPIS pilot).”

Medical Gas Research: “The role of oxygen in cluster headache.”

Nursing2003: “How do I choose a supplemental oxygen delivery device?”

StatPearls: “Fraction of Inspired Oxygen.”

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