Comparison of Effects of Halothane Anaesthesia in Horses with and without Dexmedetomidine Continuous Rate Infusion

摘要

The purpose of this study was to compare the effects of halothane anaesthesia and partial intravenous anaesthesia (PIVA) using halothane and dexmedetomidine continuous rate infusion (CRI) on respiration and coagulation parameters, and recovery in healthy horses. Six healthy ponies aged between 2 and 7 years, weighing 201 ± 70 kG (mean ± SD) were subjected to either halothane or halothane–dexmedetomidine anaesthesia two weeks apart. Acid–base, blood gase, and coagulation parameters were measured at the beginning and after three hours of anaesthesia. Recovery qualities were compared between groups. The results showed that, the addition of dexmedetomidine by CRI at 1.75 μG kG–1 hour–1 to halothane anaesthesia slightly reduced halothane requirement for maintenance of surgical anaesthesia but had no effects on the recovery time and quality. PIVA using dexmedetomidine and halothane produced respiratory acidosis similar to halothane anaesthesia alone but with significantly more pronounced hypoxaemia. In contrast to halothane anaesthesia, a combination of halothane with dexmedetomidine caused an activation of coagulation system as detected by elevation in plasma D–dimer levels and thrombin time at 3 hours of duration