Effect of extradural Ketamine on onset time and sensory block in extradural bupivacaine-induced anesthesia

ABSTRACT

Epidural anesthesia is an appropriate approach for surgical operations on lower limbs, abdominal region and painless delivery. Since the application of epidural anesthesia is time-consuming and the onset of the effects of injected anesthetic drugs in epidural space is slow [about 20 minutes], therefore, the time of occupying the operating room is prolonged and this results in wasting of time of the surgeon and staff in the operating room. This study was conducted to assess the effect of bupivacaine while used with ketamine on shortening the onset time. This double blind study was done on 40 patients. All the patients were physically ASA I, II and they underwent orthopedic and urologic surgical operations. The patients were randomly divided into two groups of 20 individuals, receiving the drugs as follows study group bupivacaine 0.5% - 20 ml + ketamine 25mg [0.5ml] + adrnaline 1/200000, control group bupivacaine 0.5%, 20ml + ketamine 25mg [0.5ml] + saline 0.9%, 0.5ml + adrenaline 1/200000. After injecting the drug in epidural space in L3-L4 or L4-L5 regions, blood pressure, heartbeat, onset of anesthesia and the level of anesthesia were evaluated in all patients. Patients in both groups were compared with regard to their height, weight, sex, age and systolic blood pressure before the injection of the drugs and no significant difference was noted among them. The systolic blood pressure and heartbeat of patients in both groups were checked in 2[nd], 5[th], 10[th], 15[th], 20[th], 25[th] and 30[th] minutes after drug injection and no significant differences were found in both groups compared to pre-anesthesia status. However, the onset and level of anesthesia was statistically significant in the two groups. The onset of anesthesia in study group was 3.5 to 4 minutes faster and the anesthesia level was two segments higher than that of the control group. Results of this study demonstrated that the addition of 25mg of ketamine to bupivacaine resulted in the acceleration of the onset as well as increase the level of anesthesia in extradural bupivacaine-induced anesthesia and this might be a useful approach in emergency surgical procedures