title: Minimum effective anaesthetic volume of 0.5% ropivacaine for ultrasound-guided popliteal sciatic nerve block in patients undergoing foot and ankle surgery: determination of ED50 and ED95.
abstract: Compared to nerve stimulation or classic paraesthesia techniques, ultrasound (US)-guided popliteal sciatic nerve block requires a smaller volume of local anaesthetic. The up-and-down method was used to determine the minimum effective anaesthetic volume of 0.5% ropivacaine necessary for US-guided popliteal sciatic nerve block to achieve successful surgical anaesthesia for foot and ankle surgery. The study included 32 patients receiving an US-guided popliteal sciatic nerve bock. The starting dose of 0.5% ropivacaine was set at 30 ml, which was decreased by 3 ml if the block succeeded and increased by 3 ml if the block failed. After the injection of local anaesthetic, the degree of sensory and motor blockade of the tibial and common peroneal nerves was assessed every 5 minutes for 30 minutes. The ED50 and ED95 volumes of local anaesthetic were 6 ml and 16 ml, respectively. The success rates of sensory blockade of the tibial nerve and common peroneal nerve were 69% and 88%, respectively. The success rates of motor blockade of these nerves were 75% and 90%, respectively. The ED50 and ED95 of 0.5% ropivacaine for US-guided popliteal sciatic nerve block were 6 ml and 16 ml, respectively.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: J S
authors.initials: JS
authors.lastname: Jeong
authors.affiliation: Department of Anesthesiology and Pain Medicine, Hanyang University Hospital, Seongdong gu, Seoul, Republic of Korea.
authors.forename: J C
authors.initials: JC
authors.lastname: Shim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Hanyang University Hospital, Seongdong gu, Seoul, Republic of Korea.
authors.forename: M A
authors.initials: MA
authors.lastname: Jeong
authors.affiliation: Department of Anesthesiology and Pain Medicine, Hanyang University Hospital, Seongdong gu, Seoul, Republic of Korea.
authors.forename: B C
authors.initials: BC
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology and Pain Medicine, Hanyang University Hospital, Seongdong gu, Seoul, Republic of Korea.
authors.forename: I H
authors.initials: IH
authors.lastname: Sung
mesh_terms: D000328:Adult; D000577:Amides / Q000493:pharmacokinetics*; D000779:Anesthetics, Local / Q000493:pharmacokinetics*; D000842:Ankle / Q000601:surgery; D004305:Dose-Response Relationship, Drug; D005260:Female; D005528:Foot / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077212:Ropivacaine; D012584:Sciatic Nerve / Q000187:drug effects*; D018084:Ultrasonography, Interventional / Q000379:methods*
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine
keywords: ropivacaine; sciatic nerve block; ultrasound