title: Positive pressure ventilation with the laryngeal mask airway in non-paralysed patients: comparison of sevoflurane and propofol maintenance techniques.
abstract: We have compared anaesthetic maintenance and emergence characteristics of propofol and sevoflurane with the laryngeal mask airway (LMA) at commonly used doses in 185 ASA I-II patients, in a randomized, prospective study. Anaesthesia was induced with propofol 2.5-3.5 mg kg-1 and fentanyl 1-3 micrograms kg-1. Neuromuscular blocking agents were not used. All patients underwent positive pressure ventilation (PPV) with tidal volumes of 6-8 ml kg-1 to maintain normal end-tidal carbon dioxide concentration. Anaesthesia was maintained with 66% nitrous oxide in oxygen and infusion of propofol 6 or 8 mg kg-1 h-1, or 1% or 1.5% end-tidal sevoflurane. There were no failed insertion attempts and adequate ventilation was achieved in all patients. During emergence, there was a greater incidence of excitatory phenomena with 1% and 1.5% sevoflurane (95% confidence intervals (CI) 4-19%) compared with propofol (95% CI 0-4%). Sevoflurane 1.0% (95% CI 37-71%) was associated with the greatest overall incidence of respiratory and haemodynamic problems. This was significantly higher compared with propofol 6 mg kg-1 h-1 (95% CI 19-36%). Shorter times to LMA removal were observed with 1% and 1.5% sevoflurane compared with propofol (P < 0.0002). Postoperative problems did not differ between groups. We conclude that propofol 6-8 mg kg-1 h-1 and 1.5% sevoflurane were suitable for maintenance of anaesthesia for musculoskeletal surgery in non-paralysed ASA I-II patients undergoing PPV with the LMA. Emergence was more rapid with sevoflurane, but was associated with more excitatory phenomena.
authors.affiliation: Department of Anaesthesia and Intensive Care Medicine, Leopold-Franzens University, Innsbruck, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Keller
authors.forename: H J
authors.initials: HJ
authors.lastname: Sparr
authors.forename: J R
authors.initials: JR
authors.lastname: Brimacombe
mesh_terms: D000328:Adult; D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D018686:Anesthetics, Intravenous; D004305:Dose-Response Relationship, Drug; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D017214:Laryngeal Masks; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage; D008875:Middle Aged; D009141:Musculoskeletal System / Q000601:surgery; D009609:Nitrous Oxide; D011175:Positive-Pressure Respiration; D011183:Postoperative Complications; D015742:Propofol; D011446:Prospective Studies; D000077149:Sevoflurane
chemical_list: D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D000077149:Sevoflurane; D009609:Nitrous Oxide; D015742:Propofol