Fluid Challenge and Plasma Volume, During Surgery

60 patients scheduled for laparoscopic abdominal surgery, with a duration exceeding 90 minutes will be included in the study. These are randomized to three different groups (20 in each groups): The first group of patients will receive boluses of acetated Ringers 4 ml/kg body weight. The second albumin 4 ml/kg body weight and the third group albumin 20% 1 ml/kg body weight.

Hemoglobin, albumin and colloid osmotic pressure (COP) is sampled the day before surgery and in the morning directly prior to the anesthesia. Bioimpedance, urine osmolality and urine-creatinin are also measured. After induction of surgery a Cardio Q probe is inserted threw the nose into the esophagus, for circulatory measurements. Initial/baseline blood samples are taken after insufflation of carbon dioxide to the abdomen. Before every bolus of fluid and 5, (10), 15, 20, 30, 40, (50) and (60) minutes new blood samples are taken for determination of hemoglobin, albumin and COP. Artery blood gases are sampled 15 minutes after every infusion or depending on the clinical need.

Inclusion criteria

• Written consent to participate in the study
• For women: relevant contraceptive, menopausal or a negative pregnancy test.
• ASA category I to III
• Laparoscopic abdominal surgery, with a duration of at least 90 minutes.
• 18 to 85 years

Exclusion criteria

• Patients with known cardiac failure
• <18 or >85 years
• known allergy to albumin
• extracellular hyperhydration or hypervolemia
• kidney failure
• pregnancy or planned pregnancy