Figure 2: Analysis of arterial blood samples. The difference in the levels of arterial blood PaCO2 (a), pH (b), and Spo2 (c) was not significant at each time point in the three groups; the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2, oxygen index) in the high hypercapnia group was significantly higher than that in the low hypercapnia group and control at T3 and T4 (d). T1: before operation; T2: 30 min after pneumoperitoneum; T3: 24 h postoperation; T4: 72 h postoperation. Compared with control group; #compared with low hypercapnia group.