Effect of Arterial Oxygen Partial Pressure on Mixed Venous Oxygen Saturation

"After the stabilization of cardiopulmonary bypass, in the first half of patients, fraction of inspired oxygen would be set at 0.5 and maintained for 5 minutes (T0), then it would be changed to 1.0 and maintained for 5 minutes (T1). Again, fraction of inspired oxygen would be resumed to be 0.5 and maintained for 5 minutes (T2).~In the other half of patients, the direction of change in fraction of inspired oxygen will be reversed as follows. It will be set at 1.0 and maintained for 5 minutes (T0), then changed to 0.5 and maintained for 5 minutes (T1), and finally to 1.0 and maintained for 5 minutes (T2)."