A Comparative Study Of 0.5 % Ropivacaine With Clonidine Versus 0.5 % Ropivacaine With Dexamethasone For Duration Of Postoperative Analgesia In Supraclavicular Brachial Plexus Block For Upper Limb Surgery

Abstract

Background and Aim:  Brachial plexus is a safe and useful method for upper limb surgery with an added advantage of postoperative analgesia.  Several adjuvants to local anaesthetics have been studied and described in literature to hasten the onset and prolong the duration of block. We aimed to compare the duration of postoperative analgesia between clonidine and dexamethasone as adjuvants to 0.5% ropivacaine in supraclavicular brachial plexus block for upper limb surgeries.

Material and Methods: A total of 70 patients between age groups of 18-60 years belonging to ASA 1 and 2 scheduled for upper limb surgery were included in the study. They were randomly allocated into two groups (RC and RD) of 35 patients each. Group RC received 35ml of 0.5% ropivacaine with 1ug/kg of clonidine diluted to 2ml to normal saline. Group RD received 35 ml of 0.5% ropivacaine with 8mg of dexamethasone (2ml).The mean time of onset of sensory block, duration of postoperative analgesia, postoperative mean VAS scores and mean sedation score were compared between the 2 groups. Pearson’s chi square test and unpaired t test were used for categorical and continuous variables respectively and p< 0.05 was considered significant.

Results: The duration of postoperative analgesia was observed to be much longer in group RD (1257.09 +90.2 minutes) as compared to group RC (854.03+42.56 minutes), the difference being statistically significant. The time of onset of sensory block in case of radial nerve distribution was more rapid in group RD (6.57+2.65 minutes) as compared to group RC (8.57+ 3.11 minutes). In median, ulnar and musculocutaneus nerve areas the differences were statistically insignificant.

Postoperative VAS scores were lower in group RD than in group RC, the differences being statistically significant at 6 hrs, 12 hrs and 24 hr (p< 001). Both the groups were oriented without sedation at any given time. None of the patients had any bradycardia, hypotension or any other side effects.

Conclusion: It can be concluded that dexamethasone as an adjuvant to 0.5% ropivacaine produces more prolonged postoperative analgesia as compared to clonidine without significant sedation or any side effects.