Pathophysiology of respiratory failure

SummaryRespiratory failure (RF) is defined as a disturbance in gas exchange in the respiratory system which produces in arterial BGA a PaO2 < 60 mmHg (hypoxaemia) and/or a PaCO2 > 50 mmHg (hypercapnia). However hypoxaemic normocapnic (or hypocapnic) RF due to the failure in gas exchange is very common and should be separated from mechanical RF. Respiratory failure (hypercapnic) with or without hypoxaemia related to a failure in the respiratory pump. This review is focused on the pathophysiology of the mechanical RF less well known amongst anaesthesiologists.