General Anesthesia With Xenon in Inspiratory Concentrations of 50% and 70% and Total I.V. Anaesthesia.

Inclusion Criteria: * Patient ≥ 50 years old * ASA (American Society of Anaesthesiologists) Physical Status III * Patient with increased risk of perioperative cardiac complications (Revised Cardiac Risk Index\>=2) * Surgical operation: laparotomy or orthopaedic surgery or laparoscopy * Planned duration of general anaesthesia in the range of 2-6 hours * Patient willing and able to complete the requirements of this study including the signature of the written informed consent Exclusion Criteria: * Patient with severe impairment of cardiac function (Left Ventricular Ejection Fraction \< 35%) * Patient with drug-eluting stent placed within 12 months prior to selection * Woman of child-bearing potential not implementing adequate contraceptive methods * Pregnant or lactating woman * Surgical procedure in emergency * Chronic opioids pain therapy * Serious illness or medical conditions which are possible contra indication for elective general anaesthesia or administration of intra operative treatments, or which are interfering with the monitoring devices, such as: * Myocardial infarction within 6 months prior to selection * Any significant history of allergy/hypersensitivity to any drugs used during the study, to silicone or to latex * Severely impaired hearing * Known severe neurological disorders * Any medical condition which does not justify the trial participation in the investigator's judgement * General anaesthesia within 7 days prior to selection * Laparotomy within 3 months prior to selection, only for patients undergoing laparotomy * History of drug abuse or psychiatric disorders which would impair the understanding of the necessary information or render medically or legally not able to give written informed consent * Concurrent treatment with any other experimental drugs * Participation in any other clinical trial within 4 weeks prior to selection