Physiological and biochemical variables in captive tigers (Panthera tigris) immobilized with dexmedetomidine and ketamine or dexmedetomidine, midazolam and ketamine

Physiological and biochemical variables in captive tigers (Panthera tigris) immobilised with dexmedetomidine and ketamine or dexmedetomidine, midazolam and ketamine were evaluated. Thirty tigers received either dexmedetomidine (0.025 mg/kg) and ketamine (3 mg/kg) (group DK) or dexmedetomidine (0.0125 mg/kg), midazolam (0.1 mg/kg) and ketamine (3 mg/kg) (group DMK). Heart rate, SPO₂ and blood pressure were measured at five-minute intervals. Arterial pH, PO₂, PCO₂, glucose, K+ and arterial and venous lactate were measured at 15 and 45 minutes after immobilisation. A generalised linear mixed model was used for statistical comparison. There was no difference within or between groups at any time point for any measured variable. Measured PO₂ was 73.2±17.5 mm Hg and SPO₂ was 88.9±10.8 per cent. Systolic, mean and diastolic blood pressures were 170.5±48.4, 138.9 ±41.8 and 121.8±37.2 mm Hg, respectively. Venous lactate was higher than arterial lactate within groups at each time point. Seizure-like behaviour was observed in 25 per cent of tigers in group DK but not in group DMK. The addition of midazolam into a protocol for immobilisation of tigers did not result in a difference in any of the measured variables but may have prevented the development of seizure-like behaviour.