An opioid-free anaesthesia (OFA) technique for dorsal laminectomy in a dog subsequent to severe bradycardia and hypothermia after previous subcutaneous methadone administration

Abstract

A 6-year-old, male, crossbreed dog presented for investigation and treatment of neck and thoracic limb pain. Frequent and repeated subcutaneous methadone administration resulted in severe side effects, including bradycardia, hypothermia and profound sedation. Based on the dog's previously evasive behaviour, suspected cervical myelopathy and technical impracticality, the decision was made not to antagonise opioid effects. Supportive treatment was given until general anaesthesia for diagnostic imaging, and surgery was deemed appropriate. In veterinary medicine, opioids are considered the gold-standard analgesics; therefore, perioperative analgesia can be challenging when previous opioid use in a patient caused side effects. This case report presents an opioid-free anaesthetic technique for magnetic resonance imaging and dorsal laminectomy in a dog. As a part of a balanced and multimodal approach, ketamine, dexmedetomidine, paracetamol, gabapentin, lidocaine and bupivacaine were included in the anaesthetic protocol; with meloxicam discontinued before surgery due to repeated episodes of vomiting and regurgitation.