Optimal Cardiopulmonary Bypass and Anticoagulation Management Strategies in Obese Patients Undergoing Cardiac Surgery

Inclusion Criteria: * Obese patients (BMI ≥ 30kg/m2) * Planned cardiac surgery * Age ≥ 18 years Exclusion Criteria: * Permanent pacemaker * Known intolerance to protamine * Known or suspected allergy to the used antifibrinolytic agent * Refusal to receive blood products * Planned off pump coronary artery bypass * Planned peri-operative use of desmopressin * Known Heparin-induced thrombocytopenia * Known deficiency in protein C, protein S, antithrombin or homozygous factor V Leiden * Known congenital bleeding disorders * Current endocarditis * Planned hypothermic circulatory arrest (\<28C) * Two or more cardiac surgery procedures * Emergency cardiac surgery procedures (medically required within 24hours of presenting with acute symptoms) * Planned CPB priming with red blood cells * Any known autoimmune disease * Any history of stroke or non-coronary thrombotic disorders including deep venous thrombosis and pulmonary embolism * Significant (≥50%) carotid artery stenosis * Patient dosed with low molecular weight Heparin less than 24h before surgery * Females of childbearing potential who are pregnant, breast-feeding or intend to become pregnant or are not using adequate contraceptive methods * Confirmed ST elevation myocardial infarction (STEMI) within 7 days * Pre-operative platelet count \<100,000/microliter * Anaemia (Hematocrit \<32% for females, \<35%for males) * Dosed with clopidogrel or ticagrelor within the last 5 days prior to surgery, or prasugrel within 7 days * Dosed with GPIIb/IIIa receptor blockers (Abciximab, Tirofiban, Eptifibatide) ≤ 24 hours prior to surgery * International ratio (INR) \>1.5 on the day of surgery in patients treated with vitamin K antagonist * Liver dysfunction (aspartate aminotransferase (AST) or alanine aminotransferase (ALT) increased ≥ 2-fold above the upper limit of local laboratory normal ranges) * Renal failure (creatinine ≥ 175 micromol/L or dialysis) * Current thromboembolic disease other than myocardial infarct * Patients who have pre-donated autologous blood * Patient presenting with a resistance to Heparin