| P value | Without bucking | With bucking |
|
| 0.001 | 25 (58%) | 18 (42%) | Alfentanil |
| 32 (74.5%) | 11 (25.5%) | Lidocaine | |
| 25 (58%) | 18 (18%) | Alfentanil-Lidocaine | |
| 12 (28%) | 31 (72%) | Witness |