title: Brachial plexus block: Comparison of two different doses of clonidine added to bupivacaine.
abstract: BACKGROUND
  The role of clonidine as an adjuvant to local anesthetic agents in brachial plexus block (BPB) has been extensively studied. However, till date there has been no consensus about the ideal dose of clonidine for this purpose. This study was carried out to evaluate two doses of clonidine-1 and 2 g/kg, added to 0.5% bupivacaine, with regard to onset and duration of sensorimotor blockade, hemodynamic effects, postoperative analgesia, and adverse effects.
  
  
  METHODS
  Sixty adult patients undergoing upper limb surgeries were randomly allocated into two groups. Thirty patients received 1 g/kg clonidine (group I) and the rest received 2 g/kg clonidine (group II) added to 30 mL of 0.5% bupivacaine through nerve stimulator-guided supraclavicular BPB. The onset and duration of sensorimotor blockade, hemodynamic variables, duration of analgesia, level of sedation, and adverse effects was assessed.
  
  
  RESULTS
  The onset of sensorimotor block was earlier in group II (9.9 ± 4.1 min for sensory block and 13.2 ± 6.7 min for motor block) than in group I (15.9 ± 6.8 min for sensory block and 18.5 ± 7.8 min for motor block). The duration of analgesia was also prolonged in patients receiving the higher dose (21.0 ± 2.96 h vs. 14.9 ± 3.0 h). Although hemodynamics remained comparable in both the groups, incidence of hypotension and bradycardia was higher in group II as compared to group I. The sedation was clinically and statistically more in group II patients (43% vs. 17%).
  
  
  CONCLUSIONS
  Higher dose of clonidine in BPB hastens the onset, prolongs the duration of sensorimotor blockade and postoperative analgesia without significant hemodynamic alterations. It also causes more sedation, which although ensures patient comfort in most cases, but might be undesirable in certain situations.
authors.affiliation: Department of Anaesthesia and Intensive Care, Jai Prakash Narayan ApexTrauma Centre, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Santvana
authors.initials: S
authors.lastname: Kohli
authors.forename: Manpreet
authors.initials: M
authors.lastname: Kaur
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Sahoo
authors.forename: Homay
authors.initials: H
authors.lastname: Vajifdar
authors.forename: Pramod
authors.initials: P
authors.lastname: Kohli
keywords: Adjuvant; brachial plexus block; bupivacaine; clonidine; postoperative analgesia