A prospective randomized double blinded study to evaluate the efficacy of dexmedetomidine 50 μg intravenously and perineurally as an adjunct to 0.5% ropivacaine for supraclavicular brachial plexus block

Abstract

Background: Dexmedetomidine, highly selective α2 agonist is used as an effective adjuvant to various local anesthetics in regional anesthesia. We have conducted this study to know the efficacy of dexmedetomidine through two routes i.e intravenous and perineural routes with ropivacaine for supraclavicular brachial plexus block in elective forearm surgeries.

Methodology: After the institutional ethical committee clearance, 60 patients aged between 18 to 60 years, belonging to ASA class I and II were randomly divided into two groups of 30 each after a detailed informed consent. Group DPN received 0.5% ropivacaine 28 ml + 2 ml of dexmedetomidine 50 μg perineurally and 100 ml of 0.9% normal saline intravenously. Group DIV received 0.5% ropivacaine 28 ml + 2 ml 0.9% normal saline perineurally and 50 μg of Dexmedetomidine in 100 ml of 0.9% normal saline intravenously. Primary objectives was to know the time of sensory onset, motor onset, time for complete motor and sensory block, total duration of sensory and motor block and total duration of analgesia. Secondary objectives were hemodynamic parameters, sedation scores and adverse events. Statistical methods were carried out through the SPSS for Windows (version 16.0)

Results: The demographic profile of the patients like age, sex, height, weight, BMI were similar in both groups. The sensory and motor onset time as well as time for complete sensory and motor block was earlier in Group DPN than Group DIV. The sensory block duration was prolonged in Group DPN (686.33 ± 52.22 min) compared to Group DIV (371 ± 38.98 min) [p < 0.001]. The motor block duration was also significantly prolonged in Group DPN (593.50 ± 58.12 min) compared to Group DIV (319.50 ± 26.47 min) [p < 0.001]. The total duration of analgesia was also significantly prolonged in Group DPN (701.83 ± 44.92 min) compared to Group DIV (405.16 ± 30.86 min)[p < 0.001]. Two patients had bradycardia and one patient had hypotension in Group DIV. Ramsay sedation scores in both the groups were < 3.

Conclusion: Dexmedetomidine is an excellent adjuvant to ropivacaine for supraclavicular block. Perineural dexmedetomidine offers a better block quality and a prolonged duration of analgesia compared to intravenous dexmedetomidine with minimal side effects