Sedative and cardiopulmonary effects of intranasal butorphanol with midazolam or dexmedetomidine in New Zealand white rabbits

BackgroundThis study aimed to compare the sedative and cardiopulmonary effects of intranasal (IN) administration of dexmedetomidine-butorphanol (DB) and midazolam-butorphanol (MB) combinations in New Zealand white rabbits. MethodsEight New Zealand white rabbits were sedated by IN administration of a combination of 0.1 mg/kg dexmedetomidine and 0.4 mg/kg butorphanol (DB treatment) and 2 mg/kg midazolam and 0.4 mg/kg butorphanol (MB treatment). The electrocardiogram, pulse rate (PR), respiratory frequency (f(R)), arterial haemoglobin oxygen saturation (SpO(2)), fraction of expired carbon dioxide (EtCO2), rectal temperature (RT), noninvasive mean arterial pressure (MAP), noninvasive systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) were recorded. The onset of sedation, duration of sedation and sedation score (SS) were also noted. ResultsThere were no significant differences in the EtCO2, RT, MAP, SAP and DAP measurements between treatments. The PR significantly decreased in DB compared with MB over time (p = 0.001). Compared with baseline, SpO(2) decreased over time in both treatments. The SS was significantly elevated over time in DB compared with MB (p = 0.002). LimitationsNo pharmacokinetic information was available for either treatment, so the findings should be interpreted cautiously. ConclusionsIN DB provides more effective sedation than MB, but cardiopulmonary impairment was observed in both treatments.