Partially antagonisable anaesthesia of the small hedgehog tenrec (Echinops telfairi) with medetomidine, midazolam and ketamine

Abstract

It was purpose of this study to establish a safe and stable anaesthesia for the small hedgehog tenrec (Echinops telfairi) which can be used for short- and long-time interventions.

Therefore 29 small hedgehog tenrecs were anaesthetized between 30 min and 4.5 h with a combination of the α₂-agonist medetomidine (0.2 mg/kg), the benzodiazepine midazolam (3 mg/kg) and the dissociative anaesthetic ketamine (20 mg/kg) (MMK). All injections were administered subcutaneously (SC) in the area of the back by carefully lifting the animal's quills with a forceps. After SC injection of MMK animals lost their righting reflexes after 3.6 min (±1.12). Oxygen was supplemented to the animals’ nose and their body temperature was maintained constantly at 30 °C by a heating plate.

Values of respiratory rate, pulse rate and oxygen saturation during the experiment were statistically evaluated by ANOVA and post-hoc tests to a level of significance determined as 5%.

The animals had stable cardiovascular and respiratory values and good muscle relaxation.

Between the 15th and the 45th minute the level of anaesthesia was deep enough for surgical interventions. Respiratory rate in this phase was 29.6±8.1 breaths/min and pulse rate was about 81.9±20 beats/min.

MMK was partially antagonised with a combination of atipamezole (1 mg/kg) and flumazenile (0.2 mg/kg) (AF) SC. Time of complete recovery took about 8.8 min (8.76±4.31 min) after administering the antagonists.

The partially antagonisable combination of MMK produced a stable anaesthesia in small hedgehog tenrecs up to 4.5 h. Therefore MMK can be used for short time interventions as well as e.g. for long-lasting neurophysiological recordings, when animals should survive the trials.