Effects of Non-invasive Ventilation (NIV) on Cerebral Oxygenation.

The proper management of brain oxygenation is an essential component of all anesthesiologic procedures. Nevertheless, the brain remains one of the least monitored organs in the perioperative phase and intensive care therapy. In the current study the effects of continuous positive airway pressure (CPAP) with different ventilation parameters (FiO2 21% - 50% - 100%) on cerebral and peripheral oxygenation (rSO2) will be examined. The INVOS Brain oximeter (IBO) is a reliable trend monitor for changes in regional cerebral oxygenation (rSO2). Therefore rSO2 will be measured on the forehead and the arm. In a randomised way the rSO2 will be monitored for 30 minutes (3x10min) with different FiO2 settings. The randomisation refers to the order of the applied FiO2, each patient is therefore its own control. Additionally vital parameters (heart rate, blood pressure, SpO2) will be recorded and blood gas analysis will be performed.