Respiratory Insufficiency

Respiratory failure is inadequate gas exchange by the respiratory system, with the result that levels of arterial oxygen, carbon dioxide or both cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia. The normal partial pressure reference values are: oxygen PaO₂ more than 80 mmHg (11 kPa), and carbon dioxide PaCO₂ lesser than 45 mmHg (6.0 kPa). Classification into type I or type II relates to the absence or presence of hypercapnia respectively.