Comparison of two different doses of dexmedetomidine added to ropivacaine in patients posted for upper limb surgery under supraclavicular brachial plexus block

Abstract

Objective: To compare the effect of adding two different doses of dexmedetomidine to ropivacaine, on onset and duration of analgesia for supraclavicular brachial plexus block in patients scheduled for upper limb orthopedic surgery.

Methodology: This prospective randomized double blind comparative study was conducted at our institution. After ethical committee approval and informed patient consents, 50 patients of ASA I, II and aged 21-60 years, who were scheduled for elective upper limb surgery and were enrolled in the study and randomly divided into two equal groups. They received either 30 ml of 0.75% ropivacaine plus dexmedetomidine (1 µg/kg) diluted with normal saline up to 5 ml (total volume = 35 ml) in Group 1 or 30 ml of 0.75% ropivacaine plus dexmedetomidine (2 µg/kg) diluted with normal saline up to 5 ml (total volume = 35 ml) in Group 2. The onset and duration of sensory and motor block, duration of analgesia, hemodynamic parameters, sedation score, VAS and side effects were recorded.

Results: Onset time of sensory and motor block were earlier in Group 2 than in Group 1 (p < 0.001). Duration of sensory and motor block and duration of analgesia were longer in Group 2 than in Group 1 (p < 0.001). There was no significant difference in the incidence of hypotension and bradycardia between both the groups (p > 0.05). There was a statistically significant reduction in number of rescue analgesic doses and total dose consumption in 24 hours in Group 2 than in Group 1.

Quantitative data are represented as arithmetic mean and standard deviation and analyzed using Student’s t test or ANOVA as per need. Qualitative data are represented as number (proportion or percentage) and analyzed using Chi square test. The levels of significance and α-error were kept 95% and 5% respectively for all statistical analyses. P values < 0.05 were considered significant.

Conclusion: Dexmedetomidine 2 µg/kg provided longer duration of intraoperative sensory and motor analgesia and prolonged postoperative analgesia in comparison to dexmedetomidine 1 µg/kg when added to inj ropivacaine 0.75%, for supraclavicular brachial plexus block without any appreciable side effects.