Figure 2. Change in partial pressure of oxygen and intrapulmonary shunting after cardiopulmonary bypass (CPB) and the proportion of atelectatic lung found after CPB. 1 = baseline; 2 = after CPB. For practical reasons, a computed tomography scan was not performed before bypass, and thus there is no value for atelectasis at baseline. *P <0.05 between two measurements in the same group. ##P < 0.01 between the control group and the other groups after CPB.