Comparison of the cardiovascular and respiratory effects and sevoflurane requirement in dogs premedicated with two doses of medetomidine and butorphanol undergoing surgical sterilization.

The aim of this study was to compare the cardiovascular and respiratory effects and sevoflurane requirement in dogs premedicated with two doses of medetomidine and butorphanol undergoing surgical sterilization. The dogs were randomly assigned to two different groups: group 1 received a lower dose of medetomidine (0.014 mg/kg) and butorphanol (0.14 mg/kg) and group 2 received a higher dose of medetomidine (0.024 mg/kg) and butorphanol (0.24 mg/kg). Anesthesia was induced with intravenous propofol and maintained with sevoflurane 2% in pure oxygen. Heart rate, SpO2, respiratory rate, EtCO2, esophageal temperature, systolic and diastolic arterial blood pressures, capillary refill time, reflexes (palpebral, pedal), jaw tone, and eye position (straight, down) were assessed. Anesthesia was monitored continuously by an anesthesiologist, and variables were recorded every 5 min. During general anesthesia, the median sevoflurane (SVO) concentrations and the median HR were significantly lower in group 2 than group 1 (p<0.05). The median HR was 96.3 (85.8-100.8) in group 1, whereas in group 2 it was 77.0 (67.5-84.6) (p<0.05). It might be concluded that the higher dose of medetomidine and butorphanol allows the use of a lower sevoflurane concentration during routine surgical treatments and ensures stable work of the cardiovascular and respiratory systems.