Evaluation of tribromoethanol, tribromoethanol-buprenorphine and ketamine-xylazine combinations for anaesthesia in Sprague-Dawley rats undergoing ovariectomy.

Effect of premedication with buprenorphine (BP) on efficacy and safety of tribromoethanol (TBE) - induced anaesthesia was evaluated and compared with anaesthesia induced by ketamine (K) and xylazine (X) combination in rats undergoing ovariectomy. Fifteen Sprague -Dawley rats (mean weight 246.5 ± 13.1g) were randomly divided into three groups. Group (TBE) received tribromoethanol solution (250mg/kg). Group (TBE+BP) was premedicated with BP (0.02mg/kg) and 30 minutes later with TBE (250mg/kg). Group KX was anaesthetized with mixture of K (43.5mg/kg) and X (6.5mg/kg). All injections were administered intraperitoneally. Anaesthetic parameters determined were onset of anaesthesia (OAN), duration of antinociception (DAN), duration of sleep (DSP) and recovery time (RCT). Rectal temperatures (RT) and respiratory rates (RR) were recorded immediately after loss of righting reflex and at ten minute interval up to 90 minute. In addition, rats were monitored for adverse signs up to one week after ovariectomy. Anaesthetic indices were compared using Student's t-test, while RR and RT were compared using analysis of variance (ANOVA). Two rats in TBE group and one rat in TBE+BP group died three days after ovariectomy. Duration of antinociception (DAN) was significantly (P= 0.0015) longer in TBE than in KX anaesthetized rats but not significantly (P= 0.054) different between TBE and TBE-BP anaesthetized rats. Also, DSP was significantly (P=0.001) longer in KX anaesthetized rats than TBE- anaesthetized rats. Similarly, the DSP was significantly (P= 0.013) shorter in TBE group than TBE+ BP anaesthetized rats. Both RR and RT decreased significantly (P< 0.0001) with time following anaesthesia in all groups. It was concluded that KX mixture provided better anaesthesia than TBE and TBE+BP, and addition of BP to TBE did not have any beneficial effect.