A comparative study on effect of addition of clonidine and fentanyl as adjuvants to local anaesthetics for subarachnoid block in patients undergoing lumbar laminectomies

BACKGROUND: The synergism between local anesthetic agents such as bupivacaine with intrathecal adjuvants such as opioids and clonidine is well established. AIMS: This study evaluates the clinical efficacy of clonidine75 μg versus fentanyl 25 μg as adjuvants to bupivacaine for spinal anesthesia. SETTINGS AND DESIGN: A prospective, randomized, parallel arm study was conducted over a period of 12 months in a tertiary care hospital. MATERIALS AND METHODS: Sixty patients were divided randomly into two groups, Group C and Group F. Patients in Group C received 2.5 ml of 0.5% bupivacaine heavy mixed with 0.5 ml (75 μg) clonidine intrathecally, and patients in Group F received 2.5 ml of 0.5% bupivacaine heavy mixed with 0.5 ml (25 μg) fentanyl intrathecally. STATISTICAL ANALYSIS: Data were analyzed using statistical tests for comparison of means. RESULTS: The mean durations of sensory block was 253.3 and 249.6 minutes in group C and group F respectively, which was statistically not significant (P = 0.76). The mean durations of motor block were 302.3 and 293.6 min, respectively, in Group C and Group F, which were also statistically not significant (P = 0.53). The mean durations of postoperative analgesia were 653.4 and 611.2 min, respectively, in Group C and Group F, which were statistically not significant (P = 0.09). Mean heart rate after 10 min was 82.5 in Group C and 87.2 in Group F, which was statistically not significant (P = 0.29), and mean arterial pressure in mmHg after 10 min was 96.3 in Group C and 97.3 in Group F, which was also statistically not significant (P = 0.86). CONCLUSION: Both clonidine 75 μg and fentanyl 25 μg when used as adjuvants to bupivacaine in the subarachnoid block have comparable beneficial results in terms of duration of analgesia, duration of motor blocks, and hemodynamic stability and also have a comparable incidence of complications.