Cardiac Output Monitoring With Estimated Continuous Cardiac Output (esCCO) vs. Transpulmonary Thermodilution (TPTD)

Inclusion Criteria: * Elective isolated off-pump coronary arteries bypass grafting. * Age \> 18 years and \< 80 yrs. * Preoperative echocardiographic ejection fraction \> 0.35 Exclusion Criteria: * Simultaneous operation (carotid endarterectomy, ventricular aneurysm resection, etc.). * Constant form of atrial fibrillation. * Severe valve dysfunction. * Peripheral vascular disease (including significant peripheral arteriopathy" which precludes the use of peripheral plethysmography). * The surgical requirement to harvest both radial arteries. * Intraaortic balloon pump. Discontinuation Criteria: * Transfer to cardiopulmonary bypass (on-pump CABG). * The PEEP test will be discontinued before standard duration in patients with PEEP-induced profound MAP decrease below 50 mm Hg, bradycardia (\< 50/min) or CIPCA \< 1.9 l/min/m2 exceeding 1 minute.