A Comparative Study of Nalbuphine, Clonidine, and Dexmedetomidine as Adjuvants to Ropivacaine in Epidural Anesthesia for Lower Limb Surgery.

Background: In epidural anaesthesia, the addition of an adjuvant to local anaesthetics enhances the efficacy, thereby providing increased duration and intensity of blockade in lower limb surgeries. The aim was to compare the efficacy, onset, and duration of sensory and motor blockade; haemodynamic changes; and sedative and analgesic effects of nalbuphine, clonidine, and dexmedetomidine as an adjuvant to ropivacaine in epidural anaesthesia.

Methodology: A prospective, randomised, double-blind study among 90 patients after taking consent was divided into three groups (30 patients each; Group D received 15 ml of 0.75% ropivacaine + injection (inj.) dexmedetomidine 1.5 μg/kg + normal saline to make it a total volume of 18 ml; Group N received 15 ml of 0.75% ropivacaine + inj. nalbuphine 0.2 mg/kg + normal saline to make it a total volume of 18 ml; Group C received 15 ml of 0.75% ropivacaine + inj. clonidine 1.5 μg/kg + normal saline to make it a volume of 18 ml, given epidurally). Data were analysed using IBM SPSS Statistics software version 23.0 (IBM Corp., Armonk, NY), and appropriate statistical tests were applied.

Results: The onset of sensory and motor block in Group D was 8.0±1.1 minutes and 10.5±1.7 minutes, respectively; in Group C, 10.3±1.4 minutes and 14.7±1.1 minutes, respectively; and in Group N, 11.3±1.5 minutes and 14.8±1.4 minutes, respectively, found to be very highly statistically significant (p<0.001). The total duration of sensory, motor block and analgesia was longest in Group D (495.5±16.1 minutes, 405.7±16 minutes, and 525.5±16.1 minutes, respectively), followed by Group N (356.8±17.7 minutes, 257±13.4 minutes, and 386.8±17.6 minutes, respectively), and shortest in Group C (309.9±13.4 minutes, 255.7±11 minutes, and 340.0±13.4 minutes, respectively), found to be very highly statistically significant. (p < 0.001). Out of 30 patients, 12 patients in Group D, six in Group C, and eight patients in Group N had sedation (Ramsay's Sedation Score (RSS) > 3). The clonidine group showed significant bradycardia, hypotension, nausea, and vomiting as compared to the others.

Conclusion: We concluded that the use of dexmedetomidine as an adjuvant to the local anaesthetic agent during epidural block hastens the onset of sensory and motor blockade, provides a longer duration of sensory and motor block, provides longer duration of analgesia, and decreases the total analgesic requirement without causing clinically significant and unmanageable side effects as compared to nalbuphine followed by clonidine.