The aim of this study is to investigate 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