Volume Kinetics for 20% Albumin in Different Clinical Situations

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

The study aims to determine the degree of plasma volume expansion and the half-life of the plasma volume expansion when 3 mL/kg of hyperoncotic (20%) albumin if infused over 30 minutes in conscious healthy volunteers, in patients undergoing surgery under general anesthesia, and on the day after major surgery when the patient is in a post surgical inflammatory state. The study also examines the increase in the plasma colloid osmotic pressure as a result of this infusion and its possible influence on markers of kidney damage.

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.

Inclusion Criteria:

• Healthy volunteers.
• Patients in ASA classes I-II scheduled for surgery.

Exclusion Criteria:

• Expected major hemorrhage during surgery.
• Blood hemoglobin concentration of < 10 g/dL.