A non-rebreather mask differs from a rebreather mask, also known as a simple face mask, in that the former prevents mixing of inhaled and exhaled air and allows for greater oxygen administration, while the latter does not. To use a non-rebreather mask, one first attaches the oxygen tubing to the oxygen tank and sets the oxygen flow rate to approximately 12-15 liters per minute. The individual administering oxygen via the mask may first occlude the valve between the mask and the oxygen reservoir bag to check that the reservoir bag is properly filling. It is also advantageous to squeeze the oxygen reservoir bag to check the patency of the valve located between the mask and the reservoir bag. The bag should be able to deflate if the valve is working properly. The administrator can also occlude the valve between the mask and the oxygen reservoir bag to fill the reservoir bag before placing it on the individual’s face. The oxygen flow rate can be adjusted until the reservoir bag deflates by approximately one-third with each breath. The individual might need some time to become accustomed to the mask. Their vital signs, including respiratory rate, oxygen saturation, and levels of consciousness may be consistently monitored throughout the course of their oxygen therapy.
In contrast, a simple rebreather oxygen mask provides a smaller amount of supplemental oxygen. Like the non-rebreather mask, a simple mask fits over the nose and mouth and is connected via tubes to an oxygen tank. Unlike a non-rebreather, a simple mask has exhalation ports, which are holes on the sides of the mask through which carbon dioxide is exhaled. There are no one-way valves, so ambient air can enter the mask and exhaled air can mix with the oxygen being delivered. This eliminates the danger of suffocation should a mask with one-way valves become disconnected from oxygen. Additionally, the simple face mask lacks a reservoir bag. The simple face mask delivers lower flow rates (about 6–10 liters per minute) and has an FiO2 of 40 to 60% oxygen. Simple oxygen masks are used when a small amount of additional oxygen is required and is commonly preferred by support personnel trained in basic first aid, such as firefighters, lifeguards, and other non-medical rescue personnel.
Both non-rebreather masks and simple face masks are non-invasive methods of oxygen delivery that do not provide positive pressure to help support the patient to breathe mechanically or reduce lung collapse, or atelectasis.
In addition to non-
rebreather masks and simple masks, there are partial
rebreather masks. Partial
rebreather masks allow some air to be recycled instead of completely preventing one from
rebreathing air. They resemble a non-
rebreather mask and consist of similar components; however, they use two-way instead of one-way valves. This allows some exhaled carbon dioxide to return to the reservoir bag. Like a simple mask, partial
rebreather masks provide high concentrations of oxygen without the risk of suffocation.