title: The reduction in minimum alveolar concentration for tracheal extubation after clonidine premedication in children.
abstract: The effects of clonidine on minimum alveolar concentration for tracheal extubation (MAC-ex) have not been elucidated. Clonidine may lead to prolonged emergence from anesthesia. We investigated the effects of oral clonidine premedication on MAC-ex and examined the emergence properties of sevoflurane in children. Sixty ASA physical status I pediatric patients, aged from 2 to 9 yr, were randomly divided into one of three groups and received placebo, clonidine 2 microg/kg, or clonidine 4 microg/kg (n = 20 each) orally, 100 min before the induction of anesthesia. The induction of anesthesia, tracheal intubation, and maintenance of anesthesia were performed with sevoflurane in air and oxygen. MAC-ex was defined according to the modification of Dixon's up-and-down method, with 0.25% as a step size. In addition, in the Control and 4 microg/kg groups, the time from tracheal extubation to spontaneous eye opening (eye-opening time) and the time from tracheal extubation to leaving the operating room (awakening time) were recorded. MAC-ex for sevoflurane (mean +/- SD) was 1.63% +/- 0.13%, 1.04% +/- 0.26%, and 0.66% +/- 0.09% respectively in the Control group, 2 microg/kg group, and 4 microg/kg group. Significant differences were observed among the three groups. The eye-opening times were 5.7 +/- 3.5 min in the Control group and 5.1 +/- 1.0 min in the 4 microg/kg group. The awakening times were 9.7 +/- 3.7 min in the Control group and 9.2 +/- 3.8 min in the 4 microg/kg group. No significant differences were observed among the groups.
  
  
  CONCLUSIONS
  Oral clonidine premedication decreased MAC for tracheal extubation for sevoflurane dose dependency and did not prolong emergence from anesthesia.
authors.affiliation: Department of Anesthesiology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba City, Ibaraki, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Yaguchi
authors.forename: Shinichi
authors.initials: S
authors.lastname: Inomata
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Kihara
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Baba
authors.forename: Yukinao
authors.initials: Y
authors.lastname: Kohda
authors.forename: Hidenori
authors.initials: H
authors.lastname: Toyooka
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage*; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000493:pharmacokinetics*; D002648:Child; D002675:Child, Preschool; D003000:Clonidine / Q000008:administration & dosage*; D020878:Device Removal; D004311:Double-Blind Method; D006801:Humans; D007442:Intubation, Intratracheal; D008738:Methyl Ethers / Q000493:pharmacokinetics*; D011229:Preanesthetic Medication; D011650:Pulmonary Alveoli / Q000378:metabolism*; D000077149:Sevoflurane
chemical_list: D000316:Adrenergic alpha-Agonists; D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D003000:Clonidine