title: The minimum effective concentration (MEC90 ) of ropivacaine for ultrasound-guided supraclavicular brachial plexus block.
abstract: The aim of this study was to determine the minimum effective concentration of ropivacaine for ultrasound-guided supraclavicular brachial plexus block. Fifty-one patients undergoing arm surgery received double-injection ultrasound-guided supraclavicular block using ropivacaine 40 ml. The concentration of ropivacaine administered to each patient started at 0.225% and then depended on the response of the previous one, based on a biased coin design up-and-down sequential method. In case of failure, the ropivacaine concentration was increased by 0.025% w/v in the next subject. In the case of a successful block, the next patient was randomised to the same concentration or a concentration 0.025% w/v less. Success was defined as complete sensory blockade of the brachial plexus 30 min after the block together with pain-free surgery. The minimum effective ropivacaine concentration in 90% of subjects was 0.257% w/v (95% CI 0.241-0.280%).
authors.affiliation: Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: G
authors.initials: G
authors.lastname: Fang
authors.affiliation: Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: L
authors.initials: L
authors.lastname: Wan
authors.affiliation: Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: W
authors.initials: W
authors.lastname: Mei
authors.affiliation: Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: H H
authors.initials: HH
authors.lastname: Yu
authors.affiliation: Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: A L
authors.initials: AL
authors.lastname: Luo
mesh_terms: D000577:Amides / Q000008:administration & dosage* / Q000493:pharmacokinetics; D000779:Anesthetics, Local / Q000008:administration & dosage*; D065527:Brachial Plexus Block / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077212:Ropivacaine; D018084:Ultrasonography, Interventional
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine
keywords: brachial plexus block; local anaesthetic; minimum effective concentration; peripheral nerve block; ropivacaine; supraclavicular approach; ultrasound guidance