Xenon in Off-pump Coronary Artery Bypass Graft Surgery

• Feasibility/Safety of xenon anesthesia [ Time Frame: Intraoperatively ] [ Designated as safety issue: Yes ]
  assessed by: depth of anesthesia, perioperative hemodynamic profile, peripheral and arterial oxygen saturation
  
  

• Major adverse cardiac and cerebral events (MACCE) [ Time Frame: up to six months after surgery ] [ Designated as safety issue: Yes ]
  death from any cause; perioperative myocardial infarction and stroke
  
  
• Incidence and duration of postoperative delirium [ Time Frame: up to five days after surgery ] [ Designated as safety issue: Yes ]
  assessed with the Confusion Assessment Method (CAM-ICU)
  
  

• Other secondary efficacy/safety measures [ Time Frame: up to five days after surgery ] [ Designated as safety issue: Yes ]
  Perioperative blood loss
  
  
• Other secondary efficacy/safety measures [ Time Frame: up to five days after surgery ] [ Designated as safety issue: Yes ]
  Requirement for blood (product) transfusion
  
  
• Other secondary efficacy/safety measures [ Time Frame: until discharge from the hospital ] [ Designated as safety issue: No ]
  Duration of postoperative intensive care unit and hospital stay
  
  
• Other secondary efficacy/safety measures [ Time Frame: up to five days after surgery ] [ Designated as safety issue: Yes ]
  Severity of postoperative critical illness as indicated by the sequential organ failure assessment (SOFA) score
  
  
• Other secondary efficacy/safety measures [ Time Frame: up to five days after surgery ] [ Designated as safety issue: Yes ]
  Perioperative renal function assessed by serum-creatinine levels and calculated creatinine clearance
  
  
• other secondary efficacy/safety measures [ Time Frame: up to five days after surgery ] [ Designated as safety issue: No ]
  Severity of postoperative critical illness as indicated by the new simplified acute physiology score (SAPS II)
  
  

The investigators hypothesize that xenon application during OPCAB-surgery performs non-inferiorly to the administration of the established anaesthetic sevoflurane with regard to haemodynamic stability, respiratory function, and depth of anesthesia. The evaluation of the outcome will include several secondary parameters such as the incidence of post-operative cardiovascular and neurovascular events, the incidence of organ dysfunction and further adverse events.

This study will further function as a pilot study for the evaluation of the incidence of postoperative delirium (POD) following OPCAB-surgery and xenon treatment. POD is a common complication of cardiac surgery/anaesthesia and may significantly affect the patients' mortality and outcome. Xenon possesses neuroprotective and anti-inflammatory qualities that may directly interfere with the pathogenesis of POD, as well as reducing other factors of perioperative organ injury including cardiac complications. Xenon´s favourable pharmacokinetic properties further result in rapid clearance from the brain, reducing any residual anaesthetic effects that may predispose to POD.