Respiratory failure is nearly any condition that affects breathing and ultimately results in failure of the lungs to function properly. The main tasks of the lungs and chest are to get oxygen into the bloodstream from air that is inhaled (breathed in) and, at the same to time, to eliminate carbon dioxide (C0₂) from the bloodstream through air that is exhaled (breathed out). In respiratory failure, either the level of oxygen in the blood becomes dangerously low, and/or the level of C0₂ becomes dangerously high.

Respiratory failure often is divided into two main types. One type is hypoxemic respiratory failure. This occurs when something interferes with normal gas exchange and too little oxygen gets into the blood (hypoxemia). All organs and tissues in the body suffer as a result. Respiratory distress syndrome, high altitudes (where there is less oxygen in the air), various forms of...