A Prospective Randomized Study to Compare Dexmedetomidine With Clonidine as an Adjuvant to Bupivacaine in Supraclavicular Brachial Plexus Block

Abstract

BACKGROUND:Various agents have been used as adjuvants to prolong the duration of action and improve efficacy of local anaesthetic agents. Recently, alpha2 agonists have become the focus of interest as adjuvants to local anaesthetics. AIM: To compare the onset time, duration of sensory and motor block and duration of analgesia when Clonidine or Dexmedetomidine is added to Bupivacaine in supraclavicular brachial plexus block. METHODS: Sixty ASA Grade I and II patients scheduled for elective forearm and hand surgeries under supraclavicular brachial plexus block were divided into two equal groups in a randomized fashion. Group C received Bupivacaine 0.25% (35cc)+Clonidine 1µg/kg and Group D received Bupivacaine 0.25% (35cc)+Dexmedetomidine 1µg/kg. Onset and duration of sensory and motor block, and duration of analgesia were compared. STATISTICAL ANALYSIS USED: Qualitative data-Chi Square test; Quantitative data-Unpaired student's 't' test. RESULTS: The onset of sensory block was earlier in Group D (8.53±0.72) than in Group C (8.18±0.55) which was statistically significant (p <0.05).There was no significant difference in onset of motor block between the two groups. Duration of sensory block and motor block was 331.43±6.693 and 271.43 6.69min, respectively, in group C, while it was 395.93±12.55 and 335.93±12.55min respectively in group D which was statistically significant (p <0.05). The duration of analgesia (Time to requirement of rescue analgesia) in group C was 407.06±10.90 min, while in group D was 497.06 10.90 and this difference was significant (p <0.001). Patients in Group D were more sedated than those in Group C (p <0.001). There was no significant difference in hemodynamics between the two groups. CONCLUSION: Dexmedetomidine when added to Bupivacaine in supraclavicular brachial plexus block enhanced the duration of sensory and motor block and also the duration of analgesia when compared with Clonidine.

Alpha2‐receptor agonists as adjuvants for brachial plexus nerve blocks—A systematic review with meta‐analyses

“…45,[63][64][65]78,80 Nineteen trials compared dexmedetomidine with clonidine in 1130 patients. 31,42,[95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111] Different doses of adjuvants were compared in seven trials. 17,22,30,40,62,64,86 One trial tested clonidine with different local anaesthetics 25 (Table 1).…”

“…The duration of BPB was 205 min (TSA adj. 95% CI 162, 249; p < .00001; 1030 patients; 19 trials) 31,42,[95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111] longer for dexmedetomidine compared with clonidine (weighted mean duration in clonidine group 481 min) (Figure 4, Appendix S7 and Table 2).…”

“…The duration of motor nerve block was 160 min (95% CI 132, 188; p < .00001; 19 trials) 31,42,[95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111] longer with perineural dexmedetomidine compared with perineural clonidine (Appendix S16).…”

“…19 trials) 31,42,[95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111] with perineural dexmedetomidine compared with perineural clonidine (Appendix S25). [95% CI 0.1, 3.2]; p = .62; 17 trials 14,16,17,19,21,22,[24][25][26]29,34,36,39,40 (Appendix S28).…”

“…High-dose dexmedetomidine was not associated with an increased risk ratio of hypotension (Appendix S34). In trials comparing dexmedetomidine with clonidine, one 105 of nine trials [97][98][99][100]102,103,105,110,111 reported hypotension in three patients receiving dexmedetomidine.…”