2003 Volume 56 Issue 5 Pages 325-331
The effects of droperidol 0.25mg/kg IV without butorphanol (Group A, n=41) or combined with butorphanol 0.0125mg/kg (Group B, n=41), 0.025mg/kg (Group C, n=40), 0.05mg/kg (Group D, n=41), 0.1mg/kg (Group E, n=43), or 0.2mg/kg (Group F, n=41) N were evaluated as premedication before inhalation anesthesia in 247 dogs. Surgical anesthesia was induced by ketamine5mg/kg IV and maintained with 50% nitrous oxide-50% oxygen-sevoflurane. All dogs calmed down and relaxed and demonstrated moderate sedation after premedication. Butorphanol produced dose-dependent enhancement sedation. The end-tidal concentration of sevoflurane during surgery varied between 2.0 and 2.3% with no significant differences among groups. Body temperature during surgery was approximately 37.7°C in group A and 36.5 37.3°C in groups B, C, D, E, and F. Throughout surgery heart rate and partial pressure of end-tidal CO2 were maintained within normal limits for dogs (approximately 110-130 bpm and 30-40mmHg). Shallow breathing occurred during surgery in 5 dogs in Group A, 6 dogs in GroupB, 7 dogs in Group C, 9 dogs in Group D, 16 dogs in Group E, and 13 dogs in Group F. Hypotension occurred in 8 dogs in Group F. Recovery from anesthesia was rapid, and most dogs were extubated by 10 minutes after cessation of anesthesia. The combination of butorphanol enhances sedation. It did not, however, enhance analgesia sufficiently to reduce the sevoflurane concentration necessary to anesthesia maintenance. Combination with 0.1 0.2mg/kg of butorphanol may induce respiratory and circulatory depression during inhalation anesthesia. We therefore recommend combining 0.25mg/kg of droperidol with 0.0125-0.05mg/kg N as premedication for inhalation anesthesia in dogs.
