Evaluation of total intravenous anesthesia withpropofol-guaifenesin-medetomidine and alfaxalone-guaifenesin-medetomidine in Thoroughbredhorses undergoing castration

[摘要] Anesthetic and cardiorespiratory effects of total intravenous anesthesia (TIVA) techniqueusing propofol-guaifenesin-medetomidine (PGM) and alfaxalone-guaifenesin-medetomidine(AGM) were preliminarily evaluated in Thoroughbred horses undergoing castration. Twelvemale Thoroughbred horses were assigned randomly into two groups. After premedication withintravenous (IV) administrations of medetomidine (5.0 µg/kg) andbutorphanol (0.02 mg/kg), anesthesia was induced with guaifenesin (10 mg/kg IV), followedby either propofol (2.0 mg/kg IV) (group PGM n=6) or alfaxalone (1.0 mg/kg IV) (groupAGM n=6). Surgical anesthesia was maintained for 60 min at a constant infusion of eitherpropofol (3.0 mg/kg/hr) (group PGM) or alfaxalone (1.5 mg/kg/hr) (group AGM), incombination with guaifenesin (80 mg/kg/hr) and medetomidine (3.0µg/kg/hr). Responses to surgical stimuli, cardiorespiratory values, andinduction and recovery characteristics were recorded throughout anesthesia. Duringanesthesia induction, one horse paddled in group PGM. All horses from group AGM weremaintained at adequate anesthetic depth for castration. In group PGM, 3 horses showedincreased cremaster muscle tension and one showed slight movement requiring additional IVpropofol to maintain surgical anesthesia. No horse exhibited apnea, although arterialoxygen tension decreased in group AGM to less than 60 mmHg. Recovery quality was good toexcellent in both groups. In conclusion, TIVA using PGM and AGM infusion was available for60 min anesthesia in Thoroughbred horses. TIVA techniques using PGM and AGM infusionprovided clinically acceptable general anesthesia with mild cardiorespiratory depression.However, inspired air should be supplemented with oxygen to prevent hypoxemia duringanesthesia.

[学科分类] 兽医学

[关键词] alfaxalone;horse;propofol;TIVA