Figure 1: The ventilatory parameters during the pneumoperitoneum. The PaCO2 levels (a) were significantly higher in the high hypercapnia group than in the low hypercapnia group and control group, whereas the pH values (b) were significantly lower in the high hypercapnia group. T1: before operation; T2: 30 min after pneumoperitoneum. Compared with control group; #compared with low hypercapnia group.