Abstract:
This case series describes the anaesthetic management of two sibling Bengal tiger (Panthera
tigris tigris) cubs that were found to have spontaneous femur fractures due to severe nutritional
secondary hyperparathyroidism. Both cubs received a combination of medetomidine
(25 μg/kg) and ketamine (4 mg/kg) intramuscularly and were maintained with isoflurane
in oxygen. An epidural injection of morphine (0.1 mg/kg) and ropivacaine (1.6 mg/kg)
was administered to both tigers, which allowed a low end-tidal isoflurane concentration to
be maintained throughout the femur fracture reduction operations. Both cubs experienced
profound bradycardia and hypotension during general anaesthesia, and were unresponsive
to anticholinergic treatment. Possible causes for these cardiovascular complications included:
drug pharmacodynamics (medetomidine, morphine, isoflurane), decreased sympathetic tone
due to the epidural (ropivacaine) and hypothermia. These possible causes are discussed in
detail.
