Multimodal balanced general anaesthesia using tiletamine-zolazepam, butorphanol, dexmedetomidine, propofol, ketamine and lignocaine in dogs

Abstract

Ten adult dogs of different ages, belonging to either sex and categorized as ASA class I, II or III, posted for various surgeries were premedicated with meloxicam (0.2 mg/kg body wt) and sedated using a combination of dexmedetomidine (5 mcg/kg), butorphanol (0.2 mg/kg), tiletamine-zolazepam (2mg/kg) administered intramuscularly. Anaesthesia was induced with propofol administered intravenously ‘to effect’. Upon anaesthetic induction, all the animals were intubated and provided 100% oxygen through a suitable breathing circuit from an anaesthesia machine. Following induction of anaesthesia and endotracheal intubation, all animals were administered a loading dose of lignocaine (2 mg/kg body wt) intravenously. Anaesthesia was then maintained using two CRIs – one comprising a combination of dexmedetomidine (2 mcg/kg/hr), lignocaine (50 µg/kg/min) and ketamine (40 µg/kg/min), and the other propofol (50 µg/kg/ min), administered simultaneously through a three-way stopcock connected to the intravenous cannula. The results indicated that the combination of tiletaminezolazepam, butorphanol and dexmedetomidine provided profound sedation. Induction of anaesthesia could be achieved with propofol @ 0.58±0.06 mg/kg body wt, intravenously. Anaesthesia could be maintained with constant rate infusions of dexmedetomidine, lignocaine and ketamine, or with propofol following a loading dose of lignocaine, without compromising cardiovascular functions. The protocol provided excellent analgesia for various soft tissue and orthopaedic procedures. Some of the complications like respiratory depression resulting in hypoventilation could easily be managed by assisted ventilation. Nociception noticed with some severely painful orthopaedic manoeuvres could also be managed by supplementing ketamine at its analgesic doses.