Carbon dioxide fills the thoracic cavity by gravity and replaces air if adequately insufflated. Because solubility of CO2 is better than that of air, occlusion or flow disruption in arteries of the brain or the heart is thought to be diminished. Despite carefully performed deairing procedures as puncturing of the ascending aorta and cardiac massage, transcranial Doppler studies revealed large amounts of emboli during the first ejections of the beating heart (van der Linden J et al. 1991). In patiens with minimally invasive approach and redo valve surgery, deairing of the cardiac chambers has become more difficult.