A comparison of propofol, thiopental or ketamine as induction agents in goats

Abstract

Objective: To compare propofol, thiopental and ketamine as induction agents before halothane anaesthesia in goats. Study design: Prospective, randomized cross-over study. Animals: Seven healthy adult female goats with mean (±SD; range) body mass of 38.9 ± 3.29 kg; 35-45 kg. Methods: The seven animals were used on 21 occasions. Each received all three anaesthetics in a randomized cross-over design, with an interval of at least 2 weeks before re-use. Anaesthesia was induced with intravenous (IV) propofol (3 mg kg -1), thiopental (8 mg kg-1, IV) or ketamine (10 mg kg -1, IV). Following tracheal intubation, anaesthesia was maintained with halothane for 30 minutes. Indirect blood pressure, heart rate, respiratory rate and arterial blood gases were monitored. The quality of induction and recovery, recovery times and incidence of side-effects were recorded. Results: Induction of anaesthesia was smooth and uneventful, and tracheal intubation was easily performed in all but two goats receiving ketamine. Changes in cardiopulmonary variables and acid-base status were similar with all three induction agents and were within clinically acceptable limits. Mean recovery times (time to recovery of swallowing reflex and to standing) were significantly shorter, and side-effects, e.g. apnoea, regurgitation, hypersalivation and tympany, were less common in goats receiving propofol, compared with the other treatments. Conclusions and clinical relevance: Propofol 3 mg kg-1 IV is superior to thiopental and ketamine as an induction agent before halothane anaesthesia in goats. It provides uneventful recovery which is more rapid than thiopental or ketamine, so reduces anaesthetic risk. © Association of Veterinary Anaesthetists, 2005.