title: Effects of inhalational anaesthesia with low tidal volume ventilation on end-tidal sevoflurane and carbon dioxide concentrations: prospective randomized study.
abstract: OBJECTIVE
  We investigated how ventilation with low tidal volumes affects the pharmacokinetics of sevoflurane uptake during the first minutes of inhaled anaesthesia.
  
  
  METHODS
  Forty-eight patients scheduled for lung resection were randomly assigned to three groups. Patients in group 1, 2 and 3 received 3% sevoflurane for 3 min via face mask and controlled ventilation with a tidal volume of 2.2, 8 and 12 ml kg(-1), respectively (Phase 1). After tracheal intubation (Phase 2), 3% sevoflurane was supplied for 2 min using a tidal volume of 8 ml kg(-1) (Phase 3).
  
  
  RESULTS
  End-tidal sevoflurane concentrations were significantly higher in group 1 at the end of phase 1 and lower at the end of phase 2 than in the other groups as follows: median of 2.5%, 2.2% and 2.3% in phase 1 for groups 1, 2 and 3, respectively (P<0.001); and 1.7%, 2.1% and 2.0% in phase 2, respectively (P<0.001). End-tidal carbon dioxide values in group 1 were significantly lower at the end of phase 1 and higher at the end of phase 2 than in the other groups as follows: median of 16.5, 31 and 29.5 mm Hg in phase 1 for groups 1, 2 and 3, respectively (P<0.001); and 46.2, 36 and 33.5 mm Hg in phase 2, respectively (P<0.001).
  
  
  CONCLUSIONS
  When sevoflurane is administered with tidal volume approximating the airway dead space volume, end-tidal sevoflurane and end-tidal carbon dioxide may not correctly reflect the concentration of these gases in the alveoli, leading to misinterpretation of expired gas data.
authors.affiliation: Anesthesia Department, General Hospital, Hospital Universitario Virgen del Rocío, Sevilla, Spain. Electronic address: mdlmattam@hotmail.com.
authors.forename: M
authors.initials: M
authors.lastname: de la Matta-Martín
authors.affiliation: Anesthesia Department, General Hospital, Hospital Universitario Virgen del Rocío, Sevilla, Spain.
authors.forename: D
authors.initials: D
authors.lastname: López-Herrera
authors.affiliation: Anesthesia Department, General Hospital, Hospital Universitario Virgen del Rocío, Sevilla, Spain.
authors.forename: J C
authors.initials: JC
authors.lastname: Luis-Navarro
authors.affiliation: Anesthesia Department, General Hospital, Hospital Universitario Virgen del Rocío, Sevilla, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: López-Romero
mesh_terms: D000328:Adult; D000368:Aged; D000770:Anesthesia, Endotracheal / Q000379:methods*; D000769:Anesthesia, Inhalation / Q000379:methods*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000097:blood*; D002245:Carbon Dioxide / Q000097:blood*; D005260:Female; D006801:Humans; D058926:Intraoperative Awareness; D007442:Intubation, Intratracheal; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage / Q000097:blood*; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy; D011013:Pneumonectomy; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods*; D000077149:Sevoflurane; D013990:Tidal Volume
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D002245:Carbon Dioxide; D000077149:Sevoflurane
keywords: Anaesthetics; Anestesia; Espacio Muerto respiratorio; Farmacocinética; Hipoventilación; Hypoventilation; Inhalación; Inhalation; Pharmacokinetics; Respiratory dead space; Sevoflurane; Sevoflurano; Tidal volume; Volumen corriente