Oxygen makes up about 21 per cent of the air we breathe. In emergency situations, medical professionals use special types of oxygen masks to help patients breathe more easily. The two types of masks you will see them using are rebreather and non-rebreather masks.
A rebreather mask is defined as one that has a soft plastic reservoir bag attached at the end of it that saves one-third of a person's exhaled air, while the rest of the air gets out via side ports that are covered with a one-way valve to allow for this. The carbon dioxide acts as a way to stimulate breathing.
A non-rebreather is defined as one that has several one-way valves in the side ports. This type of mask also has a reservoir bag attached, but the bag has a one-way valve that prevents the exhaled carbon dioxide from getting into the reservoir.
The purpose of such masks is to deliver high amounts of oxygen to people during emergency situations, such as hypoxia (lack of oxygen), respiratory disease, cardiac disease, shock, trauma, severe blood loss and seizures.
Other types of masks
There are several other types of masks, including bag valve mask (a manual respirator that delivers pure oxygen to the patient), aviator masks, masks used by those in an aeroplane in emergency situations and a self-contained breathing apparatus used by firefighters.
Since oxygen is a flammable substance, there should always be a "No Smoking" sign posted when a person is receiving oxygen. Those that use oxygen at home should be aware of all dangers involved, such as using the oxygen close to stoves or portable heating units. Oxygen tanks should also be held in a special cart to avoid bumping or dropping it.