There are many different types and sizes of oxygen masks. They range in size to fit children to large adults. Different masks are needed for the different medical conditions or emergencies. Also the masks have room to attach humidifiers or concentrators depending on need. It is important to start with knowing about the basic masks.
Nasal Cannula
While this is not a mask, it is a simple way to get oxygen into the body. This is made of a simple tube with two nasal prongs. The prongs are approximately 3 to 5mm long and are inserted into the nose. This type of delivery system will give around 22 to 44 percent oxygen.
Face Mask
More properly known as an oral nasal face mask, it is made to cover the nose and mouth. There is also another type of face mask that covers the whole face, but is rarely used. This mask works well when the cannula is not tolerated. Often a standard face mask does not form that great of a seal around the face so oxygen will leak out the sides of the mask near the cheek. Due to the leakage out of the sides of the mask, it is hard to know what percentage of oxygen is delivered.
Nonrebreathing Mask
This type of mask is used more in emergency and pre-hospital settings when the patient has been exposed to chemicals or gases like carbon monoxide or carbon dioxide. The breathing rate is usually adequate but there are still signs of hypoxia. The expelled gas from the lungs escapes through two valves at the cheek area of the mask to keep him from re-breathing the air. This mask also has an oxygen reservoir bag that should not deflate completely as he breaths in. Nonrebreathing masks deliver up to 90 percent oxygen.
Bag Valve-Mask
This mask is also used in a medical emergency and applied when people need help breathing. Breathing can be too fast, too slow or not at all. All these situations require assisted artificial ventilation. Mouth to mouth or mouth to mask are other forms of assisted ventilation. The bag valve-mask (BVM) is composed of a reservoir bag for oxygen, the bag, then the face mask. This mask can be used with or without supplemental oxygen, which is different than the other masks. This form of ventilation will also be better tolerated than mouth to mask in a conscious patient breathing too slow or too fast. In an emergency setting, with someone unconscious, it will usually require two EMS professionals to get a proper face seal and assist with ventilation. The bag will deliver as much oxygen as can be squeezed out of the bag by hand. Mouth to mask/mouth assisted ventilation delivers a larger volume of air but the BVM will deliver a much higher concentration of oxygen. This system can deliver up to 100 percent oxygen if there is a good seal on the face and it is attached to an oxygen cylinder.
References
- Mountain Side Medical: Oxygen Masks
- "Emergency Care and Transportation of the Sick and Injured;" American Academy of Orthopedic Surgeons; 2005.
