A non-rebreather mask is a medical device that helps deliver oxygen in emergency situations. It consists of a face mask connected to a reservoir bag that’s filled with a high concentration of oxygen. The reservoir bag is connected to an oxygen tank.

The mask covers both your nose and mouth. One-way valves prevent exhaled air from reentering the oxygen reservoir.

A non-rebreather mask is used in emergency situations to prevent hypoxemia, also known as low blood oxygen. Conditions that disrupt your lungs’ ability to uptake oxygen or your heart’s ability to pump blood can cause low blood oxygen levels.

If your blood oxygen levels drop too low, you can develop a condition called hypoxia, where your essential tissues become oxygen-deprived.

A non-rebreather mask may be used after traumatic injury, smoke inhalation, or carbon monoxide poisoning to keep blood oxygen levels within a normal range.

In this article, we explain how non-rebreather masks work and how they differ from other masks used during oxygen therapy.

A non-rebreather face mask fits over your mouth and nose and attaches with an elastic band around your head. The mask is connected to a plastic reservoir bag filled with a high concentration of oxygen. The mask has a one-way valve system that prevents exhaled oxygen from mixing with the oxygen in the reservoir bag.

When you inhale, you breathe in oxygen from the reservoir bag. Exhaled air escapes through vents in the side of the mask and goes back into the atmosphere.

Non-rebreather masks allow you to receive a higher concentration of oxygen than with standard masks. They’re generally only used for short-term increases in oxygenation.

Non-rebreather masks aren’t commonly used because they come with several risks. Disruptions in airflow can lead to suffocation. You can potentially choke if you vomit while wearing the mask if you’re sedated or unconscious. A healthcare provider usually remains in attendance during use of this type mask.

A non-rebreather mask can deliver between 60 percent to 80 percent oxygen at a flow rate of about 10 to 15 liters/minute (L/min). They’re useful in situations when people have extremely low levels of blood oxygen, since they can quickly deliver oxygen to your blood.

A partial rebreather mask looks similar to a non-rebreather mask but contains a two-way valve between the mask and reservoir bag. The valve allows some of your breath back into the reservoir bag.

It’s difficult to obtain as high of a blood oxygen concentration with a partial rebreather since the oxygen concentration in the reservoir bag becomes diluted.

Both types of masks may be used in emergency situations. A medical professional will determine which mask to use based on your specific condition.

A simple face mask is usually used to deliver a low to moderate amount of oxygen. A simple mask contains holes on the sides to let exhaled air through and to prevent suffocation in case of a blockage.

It can deliver around 40 percent to 60 percent oxygen at 6 to 10 L/min. It’s used for people who can breathe on their own but may have low blood oxygen levels.

A simple face mask doesn’t deliver as high of an oxygen concentration as a non-rebreather mask but is safer in the case of a blockage. A medical professional will make a decision of which type of oxygen delivery system is needed based on the specific condition being treated and blood oxygen levels.

A rebreather mask is a misnomer and doesn’t exist in the context of oxygen therapy. The term “rebreather mask” usually refers to a simple mask.

Non-rebreathing masks are not available for home use. A non-rebreathing mask is meant for short-term use in situations such as transporting people to a hospital. They’re rarely used outside of an emergency department and should only be used under medical supervision. If the oxygen flow is disrupted, it can lead to suffocation.

A doctor may recommend home oxygen therapy to people with long-term conditions like chronic obtrusive pulmonary disease, severe asthma, or cystic fibrosis.

Home oxygen therapy can be delivered through oxygen tanks or an oxygen concentrator. It’s often administered through nasal cannula or tubes that insert into your nostrils. It may also be administered through a face mask.

Non-rebreathing masks are used to deliver high concentrations of oxygen in emergency situations. These masks may be used for traumatic injuries, after smoke inhalation, and in cases of carbon monoxide poisoning.

Non-rebreathing masks aren’t available for home use. However, if you have a condition like severe asthma that affects your breathing, you may benefit from a home oxygen system. Speak with your doctor about whether a home oxygen system is right for you.