title: The effect of nitrous oxide on jugular bulb oxygen saturation during remifentanil plus target-controlled infusion propofol or sevoflurane in patients with brain tumors.
abstract: During propofol/fentanyl anesthesia, a large percentage of patients have jugular bulb oxygen saturation (SjO(2)) <50%. The incidence is less with isoflurane/N(2)O. We evaluated the effect of N(2)O on SjO(2) during remifentanil-based anesthesia with concurrent propofol or sevoflurane in 20 adults undergoing brain tumor surgery. Anesthesia was randomized: Group 1 (n = 10), target-controlled infusion propofol; and Group 2 (n = 10), thiopental 2-3 mg/kg followed by sevoflurane 0.9% end-tidal. Jugular bulb and arterial blood samples for gas analysis were withdrawn during the administration of oxygen 33% with nitrogen 67% and then with N(2)O 67%. All samples were drawn before surgery and 20 min after the addition of the study gas and with an ETCO(2) 26-28 mm Hg and mean arterial pressure >90 mm Hg. Both groups had similar demographic and physiologic data. In the Propofol group, SjO(2) was 50% +/- 10% with nitrogen and 52% +/- 9% with N(2)O (not significant); in the Sevoflurane group, however, N(2)O 67% increased SjO(2) from 56% +/- 13% to 66% +/- 12% (P < 0.01). This indicates that N(2)O does not reduce the incidence of low SjO(2) values during propofol anesthesia.
  
  
  CONCLUSIONS
  This study demonstrates that nitrous oxide can increase jugular bulb venous oxygen saturation when added to sevoflurane/remifentanil anesthesia, but not to propofol/remifentanil anesthesia, in patients with brain tumors.
authors.affiliation: Department of Anesthesiology, Catholic University School of Medicine, Santiago, Chile. hmunoz@med.puc.cl
authors.forename: Hernán R
authors.initials: HR
authors.lastname: Muñoz
authors.forename: Gastón E
authors.initials: GE
authors.lastname: Núñez
authors.forename: José E
authors.initials: JE
authors.lastname: de la Fuente
authors.forename: Manuel G
authors.initials: MG
authors.lastname: Campos
mesh_terms: D000328:Adult; D019162:Anesthetics, Combined / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007601:Jugular Veins; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D009609:Nitrous Oxide / Q000494:pharmacology*; D010100:Oxygen / Q000097:blood*; D010880:Piperidines / Q000494:pharmacology*; D015742:Propofol / Q000494:pharmacology; D011446:Prospective Studies; D000077208:Remifentanil; D000077149:Sevoflurane; D015173:Supratentorial Neoplasms / Q000601:surgery*
chemical_list: D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D010880:Piperidines; D000077149:Sevoflurane; D009609:Nitrous Oxide; D000077208:Remifentanil; D010100:Oxygen; D015742:Propofol