The Effects of Intermittent Hypoxic-hyperoxic Preconditioning for Patients Undergoing Cardiopulmonary Bypass.

Perform 4 trainings daily of intermittent hypoxic hyperoxic trainings before surgery, using 40 min trainings periods, the patient will receive air with reduced oxygen content (12 %) through a mask under constant monitoring of heart rate (HR) and SpO2. As a safety measure, minimal SpO2 was set at 82 % and maximal accepted increase of heart rate was set to + 50 % of the initial HR. When these values would be reached, the supply of oxygen automatically switched to a hyperoxic gas mixture (35% - 40% O2), inhaling of which would be continued until SpO2 reached 100% (even if SpO2 would be lower before the procedure), which, depending on the rate of saturation reduction, will takes 1 to 3 min (mean 1 min and 50 s).

Perform 4 trainings daily of intermittent hypoxic-hyperoxic trainings before surgery, using 40 min trainings periods, whereas moistened air will be delivered through a mask under constant monitoring of heart rate (HR) and SpO2.