thiopental and romifidine

Two intravenous doses of romlfidine (40 and 80 micrograms/kg) and a placebo were compared as premedicants for anaesthesia induced with thiopentone and maintained using halothane in oxygen. Romifidine significantly and linearly reduced the induction dose of thiopentone; placebo-treated dogs required 15.1 +/- 3.6 mg/kg, while dogs treated with 40 micrograms/kg and 80 micrograms/kg romifidine required 6.5 +/- 1.6 and 3.9 +/- 0.3 mg/kg thiopentone, respectively. Romifidine also significantly and linearly reduced the end tidal halothane concentration necessary to maintain a predetermined level of anaesthesia; placebo-treated dogs required 1.6 +/- 0.3 per cent halothane, while dogs treated with 40 micrograms/kg and 80 micrograms/kg romifidine required 1.3 +/- 0.4 and 0.8 +/- 0.2 per cent, respectively. Romifidine produced a significant shortening in the recovery from anaesthesia, and the higher dose of romifidine significantly improved the overall quality of anaesthesia.

Topics: Adrenergic alpha-Agonists; Anesthetics, Inhalation; Animals; Body Temperature; Dogs; Dose-Response Relationship, Drug; Drug Synergism; Female; Halothane; Heart Rate; Imidazoles; Infusions, Intravenous; Injections, Intravenous; Male; Preanesthetic Medication; Respiration; Thiopental; Time Factors

The objective of this paper was to evaluate the use of romifidine as a premedicant in dogs before general anesthesia induced with propofol or thiopentone and maintained with halothane-N2O. Fifteen healthy dogs were anesthetized twice. Each dog received, as preanesthetic protocol, atropine (10 microg/kg, IM) and romifidine (40 microg/kg, IM); induction was delivered with propofol or thiopentone and anesthesia was maintained with halothane and N2O for 1 h. Some cardiovascular and respiratory variables and recovery times were recorded. Induction doses of propofol or thiopentone and the percentage of halothane necessary for maintaining anesthesia were also registered. Thiopentone as an induction agent is more respiratory depressive but is less hypotensive than propofol. Thiopentone reduces further the percentage of halothane necessary for maintaining the anesthesia. However, the quality of recovery is poorer, as the time to extubation is longer and the dogs occasionally had a violent recovery. The combination of romifidine, atropine, propofol, halothane, and N2O appears to be an effective combination for inducing and maintaining general anesthesia in healthy dogs.

Topics: Anesthesia, General; Anesthetics; Anesthetics, Inhalation; Anesthetics, Intravenous; Animals; Dogs; Female; Halothane; Hypotension; Imidazoles; Male; Nitrous Oxide; Propofol; Respiration; Thiopental