title: Optimal end-tidal concentration of sevoflurane to test an ankle clonus in children.
abstract: METHODS
  A prospective randomized study on the end-tidal concentrations of sevoflurane at which ankle clonus existed.
  
  
  BACKGROUND
  The ankle clonus reflex is a transient neurologic abnormality, which normally occurs in patients during emergence from general anesthesia.
  
  
  OBJECTIVE
  To determine the optimal end-tidal concentration of sevoflurane to test an ankle clonus in children during emergence from general anesthesia.
  
  
  METHODS
  We studied 30 children (aged 5-15 years). General anesthesia was induced with thiopental sodium. Anesthesia was maintained with sevoflurane, oxygen, and air. At completion of surgery, 3% volume of the end-tidal sevoflurane concentration was maintained for at least 10 minutes. Ankle clonus was checked at 1.0% to 0.1% volume of the end-tidal sevoflurane concentration with an interval of 0.05% volume.
  
  
  RESULTS
  Of children, 80% had bilateral ankle clonus, which was found most frequently when patients responded poorly to verbal commands. The median of the end-tidal sevoflurane concentration for a reactive ankle clonus was 0.45% volume (interquartile range 0.5% to 0.4% volume).
  
  
  CONCLUSIONS
  The ankle clonus should be tested at 0.45% volume of end-tidal sevoflurane concentration in children undergoing scoliosis surgery during emergence from the general anesthesia.
authors.affiliation: Department of Anesthesiology and Pain Medicine, and Anesthesia and Pain Research Institute, Yonsei University College of Medicine, CPO Box 1217, Seoul 120-752, Republic of Korea.
authors.forename: Chul Ho
authors.initials: CH
authors.lastname: Chang
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Yon Hee
authors.initials: YH
authors.lastname: Shim
authors.forename: Ki-Young
authors.initials: KY
authors.lastname: Lee
authors.forename: Hwan-Mo
authors.initials: HM
authors.lastname: Lee
authors.forename: Yang-Sik
authors.initials: YS
authors.lastname: Shin
mesh_terms: D000293:Adolescent; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General / Q000009:adverse effects; D000842:Ankle / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007320:Inspiratory Capacity / Q000187:drug effects / Q000502:physiology; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage*; D011446:Prospective Studies; D012021:Reflex, Abnormal / Q000187:drug effects* / Q000502:physiology*; D000077149:Sevoflurane
chemical_list: D008738:Methyl Ethers; D000077149:Sevoflurane