Anesthetic and cardiorespiratory effects of single-bolus intravenousalfaxalone with or without intramuscular xylazine-premedication in calves

[摘要] The anesthetic and cardiorespiratory effects of xylazine-alfaxalone combination wereevaluated in calves. Six calves (age 6–9 months old; weight 114–310 kg) wereanesthetized with intravenous alfaxalone 15 min after administration of intramuscularsaline (0.5 ml/100 kg) or xylazine (0.1 mg/kg; 0.5ml/100 kg of a 2% xylazine solution). Anesthesia induction was smooth andorotracheal intubation was achieved in all calves. The calves anesthetized withxylazine-alfaxalone required a smaller induction dose of alfaxalone (1.23 ± 0.17 mg/kg,P=0.010) and accepted endotracheal intubation for a significantlylonger period (16.8 ± 7.2 min, P=0.022) than the calves anesthetized withalfaxalone alone (2.28 ± 0.65 mg/kg 7.3 ± 1.6 min). At 5 min after induction, tachycardia(heart rate 166 ± 47 beats/min of heart rate), hypertension (mean arterial bloodpressure 147 ± 81 mmHg) and hypoxemia (partial pressure of arterial blood oxygen[PaO2] 43 ± 10 mmHg) were observed in the calves anesthetized withalfaxalone alone, whereas hypoxemia (PaO2 47 ± 7 mmHg) and mild hypercapnia(partial pressure of arterial blood carbon dioxide 54 ± 5 mmHg) were observed in thecalves anesthetized with xylazine-alfaxalone. Premedication with xylazine provided asparing effect on the induction dose of alfaxalone and a prolongation of anestheticeffect. Oxygen supplementation should be considered to prevent hypoxemia duringanesthesia.

[学科分类] 兽医学

[关键词] alfaxalone;calf;intravenous anesthesia;xylazine