Table 2 General characteristics of patients

Age (year)

63.3 ± 3.6

64.4 ± 3.6

64.2 ± 2.7

0.24

Gender (male/female)

19/15

14/17

18/17

0.65

BMI (kg m⁻²)

23.9 ± 4.7

24.3 ± 3.3

24.8 ± 5.1

0.37

Duration of surgery (min)

172.8 ± 59.5

179.3 ± 61.2

182.5 ± 58.4

0.54

Duration of anesthesia (min)

219.6 ± 79.2

220.9 ± 60.6

217 ± 71.4

0.97

Stomach/intestinal surgery

16/18

15/16

20/15

0.76

Preoperative respiratory function

 Normal

24 (70)

23 (74)

23 (66)

0.19

 Mild ventilation dysfunction

6 (18)

5 (16)

7 (20)

0.48

 Moderate ventilation dysfunction

4 (12)

3 (8)

5 (15)

0.25

 Smoker

12 (35)

10 (32)

13 (37)

0.53