Larsson JS, et al. - Researchers examined patients undergoing liver transplantation to determine the impacts of norepinephrine-induced changes in mean arterial pressure (MAP) on renal blood flow (RBF), oxygen delivery (RDO₂), glomerular filtration rate (GFR) and renal oxygenation (=renal oxygen extraction, RO₂Ex) early after transplantation in the recipients. They obtained data on cardiac index (CI), RBF and GFR at each target MAP and used standard formulas to calculate renal oxygen consumption (RVO₂) and extraction (RO₂Ex). They found that at MAP levels below 75 mm Hg, RBF and GFR were pressure-dependent in patients undergoing liver transplantation. In these subjects, optimal perioperative renal filtration, perfusion and oxygenation probably require targeting MAP at approximately 75 mm Hg.