The Effect of Hydroxyethylstarch 6% 130/0.4 in a Balanced Electrolyte Solution (Volulyte®) Compared to Gelatine (Geloplasma®) on Microvascular Reactivity and Tissue Oxygen Saturation During Haemodilution Measured With Near-infrared Spectroscopy

Inclusion Criteria: Adult consenting patients scheduled for elective coronary artery bypass grafting surgery on moderately hypothermic (\> 32°C) CPB without blood transfusion. Age ≥ 18 years. Exclusion Criteria: Exclusion criteria are an ejection fraction \< 25%, a known allergy to HES, admission of HES or gelatines within the preceding 2 weeks, renal insufficiency (creatinine \> 2.0 mg/dl), significant hepatic disease (liver function tests \> 3x upper limit of normal), history of cerebrovascular disease, significant carotid artery stenosis (\> 60%), perioperative use of corticosteroids, and need for vasopressor or inotropic therapy before surgery. An expected haematocrit on CPB, calculated based on preoperative haematocrit, calculated blood volume and amount of cardioplegia, of \< 23% is also considered an exclusion criterium