Sixty American Society of Anesthesiologists physical status - I - III patients were randomly assigned to receive thoracicPVB with either 20 mL of bupivacaine 0.25 % ( Group B , n = 30 ) , or 20 mL of bupivacaine 0.25 % + 1 g/kg dexmedetomidine ( Group BD , n = 30 ) .