title: Evaluation of 25%, 50%, and 67% nitrous oxide with halothane-oxygen for general anesthesia in horses.
abstract: Twenty-five percent, 50%, and 67% nitrous oxide was administered to 12 horses anesthetized with halothane and oxygen. Compared to halothane-oxygen alone, there was no significant difference in heart rate, systolic, diastolic, or mean blood pressure values, arterial pH, PaCO2, or plasma bicarbonate values when nitrous oxide was included. A significant linear reduction in PaO2 values could be correlated with N2O:O2 concentrations. The halothane level required to maintain surgical anesthesia was reduced when nitrous oxide was administered, but it was not affected by changing the nitrous oxide concentrations. Nitrous oxide concentrations greater than 25% provide no additional reduction in halothane requirement and may be accompanied by PaO2 values that pose risk to the horse.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul 55108.
authors.forename: M
authors.initials: M
authors.lastname: Testa
authors.forename: M R
authors.initials: MR
authors.lastname: Raffe
authors.forename: E P
authors.initials: EP
authors.lastname: Robinson
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary*; D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006221:Halothane; D006339:Heart Rate / Q000187:drug effects; D006736:Horses / Q000097:blood / Q000502:physiology*; D008297:Male; D009609:Nitrous Oxide; D010100:Oxygen / Q000097:blood; D012119:Respiration / Q000187:drug effects
chemical_list: D009609:Nitrous Oxide; D010100:Oxygen; D006221:Halothane