Medical Ventilators

Mechanical ventilation can be used to provide complete support, which means the ventilator is doing on the breathing for the patient. It can also be used to assist with breathing. This means the patient is still breathing on his own, but the ventilator is providing some assistance.

Before a person is placed on a medical ventilator, a breathing tube will be inserted into the airway, usually through the mouth. In some cases, a tracheotomy is performed instead. An incision is made in the trachea, and a tracheotomy tube is placed. This is usually done if long-term ventilator support is needed.

Ventilators can be set to different modes, which provide varied levels of support. A respiratory rate and a percentage of oxygen can be set. Mechanical ventilation is most often used in hospitals and can be complex.

The length of time a person stays on a medical ventilator depends on their condition. Patients who are only on a ventilator for surgery are usually extubated, which means the breathing tube and ventilator are removed. People with medical conditions that cause breathing problems may need to stay on a medical ventilator until the condition is treated and breathing improves.

Some individuals may need a mechanical ventilator for the rest of their lives. Conditions such as certain spinal cord injuries and severe brain damage may require continuous mechanical ventilation. Ventilators intended for home use are available. 

When a patient is intubated, a sedative will be delivered through intravenous (IV) therapy. Sedatives are used to stop patients from fighting the ventilator which could cause damage to the lungs. Sedation may also lessen the pain and irritation of the throat or nasal passage associated with intubation.
Negative pressure is the oldest form of mechanical ventilation. The iron lung, a huge machine that stretches from the neck to the lower abdomen, was the first used in 1929 to treat breathing problems. The negative pressure used to stimulate breathing expands the abdomen which can cut off blood circulation to the lower body. Regular movement of the legs is required to stop blood from pooling in the extremities.
Iron lungs are rarely used today due to machine size and inability of the patient to move. Negative pressure, however can be a lifesaving form of mechanical ventilation. The Biphasic Cuirass is a modern form of the iron lung used in patients that cannot or should not be intubated. The cuirass machine works with the same negative pressure as the iron lung, but is much smaller and lighter.
Mechanical ventilation is meant to be a short term treatment. Injury to the airway, lungs, and pneumonia are risks associated with forced breathing. Patients are often weaned off artificial respiration slowly by using spontaneous breathing trials to judge whether the lungs will work properly without ventilation.