Microalbuminuria increases during major surgery such as CABG, and extracorporeal circulation activates an inflammatory cascade, which may increase capillary permeability and cause microalbuminuria. The increase in capillary permeability may induce exudation of proteins from the lung capillaries into the capillary–alveolar interspace and alveoli, causing the so-called post-perfusion lung, which resembles pulmonary oedema.