Effects of 2 and 4 μg/kg/min of dopamine (DA2, DA4) on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO
) and renal oxygen extraction (RO
Ex) in postoperative patients. RBF was measured by two independent techniques, retrograde renal vein thermodilution (RBF-TD) and infusion clearance for paraaminohippuric acid (PAH), with correction for renal extraction of PAH (RBF-IC). Note that low-dose dopamine improved renal oxygenation by a profound renal vasodilation with no changes in GFR or RVO2. From  with permission.