Some of the risks of mechanical ventilation include:
Infections - The endotracheal tube in the windpipe makes it easier for bacteria to get into the lungs. As a result, the lungs develop an infection, which is called pneumonia. The risk of pneumonia is about 1% for each day spent on the respiratory ventilator. Pneumonia can often be treated with antibiotics. Sometimes the pneumonia can be severe or difficult to treat because of resistant bacteria .
Collapsed Lung - This is called a pneumothorax. The mechanical ventilator pushes air into the lungs. It is possible for a part of the lung to get over-expanded which can injure it. Air sacs may leak air into the chest cavity and cause the lung to collapse. If this air leak happens, doctors can place a tube in the chest between the ribs to drain out the air leaking from the lung. The tube allows the lung to re-expand and seal the leak. Rarely, collapse of the lung can cause death.
Lung damage - When the lungs are diseased and not functioning well, they are at greater risk of injury. The pressure to put air into the lungs with a respiratory ventilator can be hard on the lungs.
Side Effects of Medications - Patients may be given medications, called sedatives, to make them more comfortable while the respiratory ventilator pushes air in and out of the lungs. These medications make patients sleepy and help them forget unpleasant experiences. The medications can build up in the body and the patient may remain in a deep sleep for hours to days, even after the medicine is stopped. Although the doctors and nurses try hard to get just the right amount of medication for a patient, it is not easy to get it perfectly right.
Maintenance of Life - In some very sick patients, trying to keep the patient alive means that dying actually takes longer. Sometimes the lungs fail because the body is dying, and using the respiratory ventilator in place of the lungs only serves to put off what is inevitable - death. In this way, the respiratory ventilator may increase the length of time that patients are uncomfortable in their final days. Sometimes, doctors can give a good idea how likely use of mechanical ventilation will lead to a successful recovery. Very often, however, doctors can only give a rough idea of the likelihood that a patient will survive and go home after mechanical ventilation. A decision about continuing mechanical ventilation or not may come up if a patient is not showing any recovery or is continuing to get worse.