RESUMO
This prospective, randomised, observer-blinded study was conducted to compare the ease of performance and surgical effectiveness of interscalene block below the C6 nerve root with supraclavicular and infraclavicular techniques of brachial plexus block for upper arm and forearm surgery. Sixty adult patients of American Society of Anesthesiologists grade 1 to 3, undergoing upper limb surgery, were randomly allocated into three groups. Group SC received supraclavicular blockade, group IC received infraclavicular blockade and Group IS received interscalene blockade. All blocks were guided by ultrasound with nerve stimulator confirmation. The anaesthetic mixture consisted of 0.5 ml/kg of equal volumes of 0.75% ropivacaine and 2% lignocaine-adrenaline. The imaging and block performance time, onset time, success rate, duration of block, and duration of postoperative analgesia were recorded by a blinded observer. The onset time was significantly longer in the interscalene group as compared with supraclavicular and infraclavicular approaches. The imaging time and block performance time were comparable between groups. No significant differences were observed between the three groups in terms of block-related pain scores, success rates, duration of block or of postoperative analgesia. Two patients in the interscalene group developed clinically detectable phrenic nerve palsy. Our findings indicate that, although interscalene block below the C6 nerve root can provide surgical anaesthesia for forearm and hand surgery, it appears to have a longer onset time than supra- and infraclavicular approaches and an unacceptable incidence of phrenic nerve palsy.