Changes in alveolar-arterial oxygen partial pressure difference during orthotopic liver transplantation.

Changes in the alveolar-arterial oxygen partial pressure difference (PAO2-PaO2) were measured in 39 patients undergoing orthotopic liver transplantation without veno-arterial or veno-venous bypass. The operation can be divided into an initial dissection phase, an anhepatic phase when the hepatic artery, portal vein and vena cava are clamped, and a post-anhepatic phase after the vascular clamps are released. There was an initial increase in (PAO2-PaO2) during the dissection phase, followed by an immediate decrease when the liver was removed. This decrease continued throughout the anhepatic period, but a further increase in (PAO2-PaO2) occurred after release of all the vascular clamps and during abdominal closure.