Auckland DHB Cardiothoracic and Vascular Intensive Care and High Dependency Unit
Respiratory failure occurs when the respiratory system is no longer able to provide enough oxygen requirements or remove enough carbon dioxide from the body. Hypoxia (not enough oxygen is reaching the tissues) may occur unless there are interventions. Large amounts of carbon dioxide may also build up in respiratory failure.
This is the use of a ventilator (sometimes called a life support machine) to do the breathing for a patient experiencing respiratory failure. The ventilator fills the lungs with air, thereby providing oxygen to, and removing carbon dioxide from, the body via the lungs.
Usually the ventilator delivers oxygen directly into the airway of the patient. This is done using an endotracheal tube which is a plastic tube that is passed through the mouth into the larynx (the top of the trachea or windpipe). Conscious patients are usually given a medication to make them sleepy or unconscious and a muscle relaxant to help them relax while the tube is inserted.
Sometimes people may require a ventilator for a long time. If this is the case a tracheostomy (when an opening is made in the trachea) is performed and the endotracheal tube inserted into the opening.
For many very ill patients mechanical ventilation lasting only hours or a few days is enough and, after normal breathing is established, the ventilator can be removed. Unfortunately, a patient whose underlying disease is long-term may become dependent on the ventilator. Their continuing need for mechanical ventilation may be total i.e. 24 hours a day, or it may be limited i.e. only during sleep or occasionally through the day.
Noninvasive Positive Pressure Ventilation
Some patients may receive ventilation without needing intubation, with the breathing support being delivered via a sealed mask applied to the face. However noninvasive ventilation is useful only in some circumstances and in some patients.
Acute Respiratory Distress Syndrome (ARDS)
This is a life-threatening condition. It results from any illness that causes widespread inflammation of the lungs. In ARDS, fluid builds up in the air sacs of the lungs (alveoli) and other lung tissue. When the air sacs fill with fluid, the lungs can no longer fill properly with air and the lungs become stiff. This makes breathing difficult.
The main symptom of ARDS is severe shortness of breath. This may develop within minutes or gradually over a few days. A doctor may confirm a diagnosis of ARDS by:
- a chest x-ray
- arterial blood gas analysis, which measures the oxygen content in blood.
Treatment depends on the underlying cause but may include a breathing machine (mechanical ventilation) until the lungs heal.