| SPO2 (٪) | Group A (n = 20) | Group B (n = 20) | p value |
| Mean ± SD | Mean ± SD | ||
| Intraoperative: |
| ||
| Before epidural insertion | 99 ± 0.95 | 98 ± 0.92 | 0.336 |
| After epidural insertion | 97.5 ± 0.89 | 97.8 ± 1.11 | 0.276 |
| After intubation | 99.3 ± 0.47 | 98.6 ± 1.94 | 0.125 |
| After skin incision | 99.5 ± 0.51 | 98.7 ± 2.05 | 0.098 |
| 15 min | 99.3 ± 0.66 | 99.1 ± 0.31 | 0.228 |
| 30 min | 99.5 ± 0.51 | 99 ± 1.6 | 0.191 |
| 1 hr | 99.1 ± 0.55 | 98.7 ± 1.66 | 0.313 |
| After extubation | 99.3 ± 0.47 | 98.8 ± 1.41 | 0.141 |
| Postoperative: |
| ||
| 30 min | 99 ± 1.65 | 98.3 ± 1.03 | 0.116 |
| 1 hr | 99 ± 0.46 | 98.5 ± 1.51 | 0.165 |