Evaluation of the Accuracy, Safety and Robustness of a Single-input-single-output (SISO) Model-based Predictive Closed-loop System to Guide Patient-individualized ICU Sedation

Inclusion Criteria: * patients in the immediate post-operative phase after an coronary artery reconstruction surgery. * age \>= 18 years * informed consent obtained before the surgery Exclusion Criteria: * severe renal failure defined by the RIFLE Classification levels Risk, Failure and End-stage Kidney Failure * severe hepatic failure defined by a bilirubin level of \>= 3 mg/dl and/or a prothrombin level of \< 50% before the surgery * low ejection fraction defined as \< 40% * age \< 18 years * postoperative bleeding so that a new surgery is necessary * history of cardiovascular accident (CVA) * history of COPD * age \> 75 years * postoperative cardiac index \< 2.2 for more than 2 hours * SvO2 \< 60% for more than 2 hours * hypotension with a MAP \< 60 mmHg for more than 2 hours * sedation agents other than remifentanyl and propofol including also Catapressan, Risperdal, Etumine * Remifentanyl dose exceeding 0.5 µg/kg/min. * absence of informed consent