Effect of body mass index on the ED50 volume of bupivacaine 0.5% for supraclavicular brachial plexus block

The aim of this study was to determine whether the ED50 dose of bupivacaine 0.5% for supraclavicular brachial plexus block increases with increasing body mass index (BMI). This double-blind, non-randomized trial followed an up-and-down sequential allocation design. Adult patients undergoing elective upper limb surgery under ultrasound-guided supraclavicular brachial block were recruited. A preliminary study was used to guide the dosing schedule for the main study in which patients were divided into three groups according to their BMI (Group A, BMI >27 kg m−2; Group B, BMI 24–27 kg m−2; Group C, BMI