The Effect of Xylazine Premedication on the Dose and Quality of Anesthesia Induction with Alfaxalone in Goats

Abstract

Goats have been used as animal models in research and are increasingly kept as companion animals. However, information about effective anesthetic drugs is scarce in this species. The objective of this study was to evaluate the effect of xylazine premedication on alfaxalone induction. Twelve clinically healthy goats weighing 18.5 ± 2 kg were randomly assigned to two groups. Induction was performed with alfaxalone alone intravenously (ALF group) or with xylazine premedication before alfaxalone administration (XYL-ALF group). The quality of induction was scored, induction doses of alfaxalone were determined, and cardiorespiratory parameters and nociceptive thresholds were measured before any treatment(s) (baseline) and at 5, 15, 25 and 35 min after alfaxalone administration. The mean dose of alfaxalone required for induction in the ALF group was greater than that in the XYL-ALF group (p < 0.001). There were no significant changes in diastolic arterial pressure (DAP), mean arterial pressure (MAP) or systolic arterial pressure (SAP) compared to baseline in either group, while hemoglobin oxygen saturation (SpO2) was lower from 5 to 25 min (p < 0.5) in the XYL-ALF group. The nociceptive threshold was significantly higher at 5 min in the XYL-ALF group than in the ALF group (p = 0.0417). Xylazine premedication reduced the required dose of alfaxalone for anesthetic induction and produced better antinociception than alfaxalone alone. In addition, the combination of xylazine and alfaxalone allowed for successful induction; however, oxygen supplementation is necessary to counteract xylazine-associated hypoxemia.

Determination of the Minimum Infusion Rate of Alfaxalone Combined with Electroacupuncture in Goats

“…In both ALF and EA-ALF groups, echocardiographic parameters fluctuated within the clinically acceptable with insignificant differences in SV and CO reported at alfaxalone MIR time. Prior studies revealed insignificant changes in CO, CI, and SV during alfaxalone anesthesia in goats [10], horses [41], and dogs [42,43]. In this current study, the alfaxaloneinduced tachycardia is most likely the compensatory reflex for maintaining CO within the normal level range throughout the experiment [10,44].…”

“…Prior studies revealed insignificant changes in CO, CI, and SV during alfaxalone anesthesia in goats [10], horses [41], and dogs [42,43]. In this current study, the alfaxaloneinduced tachycardia is most likely the compensatory reflex for maintaining CO within the normal level range throughout the experiment [10,44].…”

“…Before anesthesia, a 22G 2.5-cm catheter was inserted into each goat's left cephalic vein. A single bolus of alfaxalone at a dose of 3 mg/kg [10] was administered over a period of 60 s for the induction with an additional dose of 1 mg/kg administered every 15 s, if needed, to facilitate tracheal intubation. A silicon endotracheal tube with 7.5 internal diameter was inserted by the aid of a 30-cm illuminated laryngoscope blade while the goats were placed into sternal recumbency.…”

“…At that point, the current was discontinued, and the volt level was recorded. To assess muscle tone, an investigator who was blinded to the delivered drug scored the degree of muscle relaxation during the experiment (Appendix A) [10]. Normal resting tone was taken a score of 2; less tone was represented by scores less than 2, and high tone was indicated by scores greater than 2.…”

“…Compared to other anesthetic agents, alfaxalone has several merits, including a broad margin of safety and fast onset of action, and less cumulative effects following repeated dosages [7]. Recently, alfaxalone has been reported to have minimal hemodynamic effects during anesthesia in goats [8][9][10] and sheep [11].…”