Respirator is a machine that assists or takes over the function of breathing, or respiration, when a person is injured or ill and has difficulty breathing independently. The use of a respirator is called artificial respiration or mechanical ventilation. A respirator helps patients who are unable to supply enough oxygen to the body or remove waste products, such as carbon dioxide, through the lungs. There are two basic types—positive-pressure respirators and negative-pressure respirators.
Today, positive-pressure respirators are more commonly used. These devices force air through a tube into the lungs under pressure. Two main types, called volume cycled and pressure cycled respirators, precisely control the amount of air taken with each artificial breath and the pressure with which the air is forced into the lungs. After the lungs are filled, the machine cuts off, and the natural elasticity of the lungs expels the air.
Negative-pressure respirators include the iron lung, which encloses the entire body except for the head, and the chest cuirass, which covers only the chest. These machines create a vacuum that causes the patient’s chest to expand, drawing air into the lungs. They then destroy the vacuum, allowing the patient’s chest to contract and expel the air.
See also Iron lung .
