title: Concomitant administration of nitrous oxide and remifentanil reduces oral tissue blood flow without decreasing blood pressure during sevoflurane anesthesia in rabbits.
abstract: OBJECTIVE
  To determine whether continuous administration of nitrous oxide and remifentanil—either alone or together—alters blood flow in oral tissues during sevoflurane anesthesia.
  
  
  METHODS
  Eight male tracheotomized Japanese white rabbits were anesthetized with sevoflurane under mechanical ventilation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), common carotid arterial blood flow (CCBF), tongue mucosal blood flow (TMBF), mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), upper alveolar tissue blood flow (UBF), and lower alveolar tissue blood flow (LBF) were recorded in the absence of all test agents and after administration of the test agents (50 % nitrous oxide, 0.4 μg/kg/min remifentanil, and their combination) for 20 min.
  
  
  RESULTS
  Nitrous oxide increased SBP, DBP, MAP, CCBF, BBF, MBF, UBF, and LBF relative to baseline values but did not affect HR or TMBF. Remifentanil decreased all hemodynamic variables except DBP. Combined administration of nitrous oxide and remifentanil recovered SBP, DBP, MAP, and CCBF to baseline levels, but HR and oral tissue blood flow remained lower than control values.
  
  
  CONCLUSIONS
  Our findings suggest that concomitant administration of nitrous oxide and remifentanil reduces blood flow in oral tissues without decreasing blood pressure during sevoflurane anesthesia in rabbits.
authors.affiliation: Department of Pharmacology, Tokyo Dental College, Misaki-cho 2-1-14, Chiyoda-ku, Tokyo, 101-0061, Japan. mkasahar@tdc.ac.jp.
authors.forename: Masataka
authors.initials: M
authors.lastname: Kasahara
authors.affiliation: Department of Dental Anesthesiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ichinohe
authors.affiliation: Department of Dental Anesthesiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Sota
authors.initials: S
authors.lastname: Okamoto
authors.affiliation: Department of Dental Anesthesiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Reina
authors.initials: R
authors.lastname: Okada
authors.affiliation: Department of Dental Anesthesiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kanbe
authors.affiliation: Department of Dental Anesthesiology, Tokyo Dental College, Tokyo, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Matsuura
mesh_terms: D000758:Anesthesia / Q000379:methods; D000818:Animals; D062186:Arterial Pressure / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D008334:Mandible; D008406:Masseter Muscle / Q000378:metabolism; D008738:Methyl Ethers / Q000008:administration & dosage*; D009609:Nitrous Oxide / Q000494:pharmacology*; D010880:Piperidines / Q000494:pharmacology*; D011817:Rabbits; D000077208:Remifentanil; D012121:Respiration, Artificial / Q000379:methods; D000077149:Sevoflurane; D014059:Tongue / Q000098:blood supply; D014140:Tracheotomy
chemical_list: D008738:Methyl Ethers; D010880:Piperidines; D000077149:Sevoflurane; D009609:Nitrous Oxide; D000077208:Remifentanil