Clinical Evaluation of Two Different Doses of Clonidine as an Adjuvant to Bupivacaine in Ultrasound-Guided Supraclavicular Brachial Plexus Block for Pediatric Upper Limb Surgeries - A Randomized Trial.

Background: Clonidine as an adjuvant to local anesthetic for regional anesthesia in upper limb surgeries has been extensively studied in adults, but there is a paucity of data regarding the dose of clonidine which is effective and safe as an adjuvant in children.

Aims: To find the dose of clonidine that prolongs the duration of analgesia without prolonging the side effects.

Settings and design: Prospective, randomized, double-blind study.

Materials and methods: After taking informed consent from the parents/guardian, 42 children aged 3-12 years who were scheduled to undergo unilateral upper limb surgeries below the elbow were randomized into two groups of 21 each. Group A was given 0.5 μg.kg^-1 of clonidine in addition to 0.5 mL.kg^-1 of 0.25% bupivacaine and Group B received 1 μg.kg^-1 of clonidine added to the same volume and concentration of local anesthetic for supraclavicular brachial plexus block under general anesthesia using ultrasound guidance. The drug administration and the recording of the observations were done by an investigator blinded to the dose of clonidine.

Statistical analysis used: Statistical testing was conducted with the Statistical Package for the Social Sciences system version SPSS 17.0.

Results: The demographic parameters and baseline hemodynamic parameters were similar in the two groups. The block failed in one child in Group A. One patient in Group A required tramadol postoperatively while none of the patients in Group B required tramadol. The mean duration of analgesia (11.35 ± 1.54 h vs. 9.94 ± 1.04 h, P < 0.001) and the duration of motor block (8.86 ± 1.0 h vs. 7.77 ± 0.55 h, P < 0.001) were significantly higher in group B. Sedation scores were higher in the recovery room in Group B. Deep sedation, bradycardia, and respiratory depression were not observed in any of the cases.

Conclusions: Clonidine 1 μg.kg^-1 when added as an adjuvant to bupivacaine for pediatric supraclavicular brachial plexus block prolongs the duration of analgesia and motor block as compared to the dose of 0.5 μg.kg^-1. However, this was at the cost of increased duration of motor block and sedation. Considering the clinical equivalence of the effect, a lower dose of clonidine would be preferable to avoid the undesirable effects.