Comparative Evaluation of Clonidine and Fentanyl as Adjuvants with Levobupivacaine for Postoperative Epidural Analgesia after Total Knee Replacement Surgery - A Randomised Double Blind Study

Background and Aims Epidural anaesthesia commonly used for inducing anaesthesia and postoperative analgesia in patients undergoing lower limb surgeries. Fentanyl as an adjuvant to epidural local anesthetic has been for long time. Clonidine is a potent and selective α-2-adrenoceptor agonist with analgesic potency. The aim of the study was to compare the effect of clonidine and fentanyl as an adjuvant to epidural levobupivacaine in total knee replacement surgery. Methods Seventy patients American Society of Anaesthesiologists Grade I or II who were undergoing total knee replacement surgery were randomly divided into two groups. Patients were allocated to one of the two groups by computer generated random selection. Group I (n=35) patients received postoperative continuous epidural infusion of levobupivacaine (1.25mg/ml) with fentanyl (2 μg/ml) whereas Group II (n=35) patients received epidural infusion of Levobupivacaine (1.25mg/ml) with Clonidine (1μg/ml) in the range of 3-7 ml/hr. Pain intensity at rest and during motion (flexion of the knee, about 30 degree) was assessed using the VAS score. Results The total number of bolus doses required in the 24 hours period was 17 doses in group I and 19 doses in group II. The difference in bolus requirement and the mean VAS score at various time intervals (0, 0.5, 1,2, 4, 8, 16, and 24 hours) in two groups was statistically insignificant. Conclusion Clonidine even in lower concentration (1mcg/ml) added as adjuvant to levobupivacaine is as effective as fentanyl (2mcg/ml), without any significant alteration in hemodynamic and side effects.