Patients with acute exacerbations of COPD have a risk for developing respiratory failure. Respiratory failure occurs when respiratory demand exceeds the ability of the respiratory system to respond. Without aggressive intervention at the point of respiratory failure, the patient can die. Aggressive therapy at this point may include mechanical ventilation.
Mechanical ventilation is a means by which air is pushed into a patient's lungs by the ventilator instead of the patient using his respiratory muscles to draw in air. Mechanical ventilation therefore reduces or eliminates the patient's work of breathing, and the patient continues to receive air into his lungs and passively exhale without any work. There are two commonly used methods for mechanical ventilation in COPD: noninvasive and invasive.
The more traditional means is invasive ventilation: an endotracheal tube, a small-diameter plastic tube, is placed into the trachea and then connected to a ventilator, which pushes air into the lungs. Invasive ventilation can be administered to patients who are unconscious or heavily sedated, and it is more effective than noninvasive ventilation.
Noninvasive ventilation is used in a conscious, cooperative patient. In this method, oxygen is delivered through a mask that forms a seal around the nose or mouth and nose. The advantages are that the mask can be periodically removed and the patient's natural protection against secretions getting into the lower airway is preserved.
Being able to come off a ventilator once placed on one, called weaning, is a common concern for patients and their families. Most patients successfully wean themselves from the ventilator once the conditions that placed them on the ventilator are sufficiently reversed. For a small percentage of patients, including those with severe COPD, it is impossible to breathe on their own again. There is no way to predict whether a patient can be weaned. However, severe lung disease and general ill health increase this risk.
COPD and Decisions About Ventilation
A patient with severe COPD can decide whether he or she ever wants to be placed on a ventilator. Another decision a person with COPD may want to make is whether to have the ventilator discontinued and to be allowed to die, if he or she is unable to breathe independently. Both decisions should be made in close consultation with the person's physician.
COPD and Chronic Ventilation
In the small group of patients unable to be liberated from mechanical ventilation, chronic ventilation may be used. If, after 2 weeks, it becomes apparent that the patient is not likely to come off the ventilator, (there is no magic number of days and physician's practices vary) a tracheostomy is performed, that is, a hole that connects to the trachea is made in the neck, a tube is inserted into the hole, and the tube is then connected to the ventilator. A tracheostomy creates a more stable airway and facilitates movement of the patient and oral care. Patients with a tracheostomy can be maintained on a ventilator indefinitely. One study found the average survival rate of patients chronically on the ventilator to be about 7 months.