摘要：

Thirty-five mature male ponies (B.Wt. 115.5-288.6 kg) were used to evaluate the anesthetic effect of continuous intravenous infusion of guaifenesin-ketamine-xylazine (GKX) mixture for castration. This GKX mixture contained 50 mg/ml guaifenesin (prepared in 5% dextrose in water), 0.5 mg/ml xylazine and either 1 mg/ml ketamine (GKX-1) or 2 mg/ml ketamine (GKX-2). Group 1 ponies were given GKX- 1 and group 2 ponies were given GKX-2. All ponies received intramuscular xylazine (1.1 mg/kg) 15 to 20 minutes before anesthesia was induced by rapid infusion of 1.1 ml/kg of GKX-1 in Group 1 and GKX-2 in group 2. Anesthesia was maintained by continuous infusion using a calibrated infusion pump. Total mean GKX dose required for induction and maintenance of anesthesia for 50 minutes with GKX- 1 and 45 minutes with GKX-2 was 4.5±0.3 ml/kg/hr and 4.3±0.2 ml/ kg/hr, respectively. Respiration rate decreased inboth groups but remained within normal limits for ponies. Heart rate was unchanged immediately following induction in either group, but heart rate was decreased at 40 to 50 minutes for GKX-1 and 30 to 50 minutes for GKX-2, reflecting the bradycardic action of xylazine somewhat more than the stimulating effect of ketamine. Recovery to standing required a mean time of 21±4 minutes with GKX-1 and 23±3 minutes with GKX-2 once the infusion was discontinued. Stability of anesthesia and degree of analgesia and muscle relaxation was judged best for GKX-2.

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