Volume Kinetics for 20% Albumin in Conscious and Anesthetized Humans With and Without Inflammation

15 volunteers, 15 patients undergoing surgery and 15 patients in the post-surgical phase will be recruited for this study because they have different degrees of vasodilatation and inflammation, which are factors of potential importance to the effectiveness of plasma volume expansion with albumin 20%. Hyperoncotic albumin should logically recruit fluid from the interstitial fluid space, but this possibility has recently been questioned in the "revised Starling equation".

The degree of plasma volume expansion and also the half-life will be estimated by population volume kinetics which uses serial analyses of the blood hemoglobin concentration and a summary measure of the excreted urine during the 5-hour experiment to calculate these outcome measures.

There is a risk that hyperoncotic solutions cause pre-renal anuria due to the rise in plasma oncotic pressure. As a safety measure we will assess the plasma oncotic pressure and relevant biomarkers of renal function during the experiments. The experiments will be ended with a slow infusion of 1 L of Ringer´s acetate to dilute any raised oncotic pressure.