Respiratory failure

Respiration is sufficient when it is able to provide enough oxygen to and remove enough carbon dioxide from the tissues. If this is not the case, there is respiratory failure. There are two types of respiratory failure, partial and global.

Partial respiratory failure, also called hypoxaemic respiratory failure or type I respiratory failure, is characterised by hypoxaemia (decreased pO2) but no hypercapnia (elevated pCO2).

Complete respiratory failure, also called hypercapnic respiratory failure or type II respiratory failure, is characterised by both hypoxaemia and hypercapnia. This is more severe and also causes respiratory acidosis.

Etiology

Hypoxaemic respiratory failure

Hypoxaemic respiratory failure occurs due to problems with gas exchange in the lungs or due to mild V/Q mismatching. This is because CO2 exchanges much more easily in the lungs than O2.

Hypercapnic respiratory failure

Hypercapnic respiratory failure occurs due to (alveolar) hypoventilation. This may be due to increased dead space or decreased minute ventilation. Etiology of hypoventilation: