Clinical efficacy of procedural sedation combined with femoral and sciatic nerve blocks for stifle and tibial surgeries in dogs

Abstract

The term procedural sedation (PS) is now popular in human anaesthetic practice where a semi-conscious state is achieved allowing the patient to be comfortable during certain therapeutic and diagnostic procedures. This raised the question of whether PS could be used in conjunction with local/regional anaesthesia in veterinary practice, to provide adequate conditions suitable for performing orthopaedic surgeries. Ten adult dogs posted for surgeries of tibia or stifle were used for the study. All the dogs were premedicated with meloxicam (0.2 mg/kg). 30 min later, all the animals were administered intramuscularly with a combination of dexmedetomidine (2 mcg/kg), butorphanol (0.2 mg/kg) and midazolam (0.2 mg/kg). Upon sedation, a loading dose of propofol (0.5 mg/kg body wt) was administered intravenously, followed by an intravenous infusion of propofol (70-150 mcg/kg/min) to maintain the sedation, till the end of surgery. Oxygen was supplied via nasal prongs at a flow rate of 6 L/min. Femoral and sciatic nerve-blocks were then achieved by injecting a combination of dexmedetomidine and bupivacaine for each nerve, through anatomical landmarks, employing a Nerve Stimulator-Mapper-Locator. Procedural sedation combined with femoral and sciatic nerve blocks provided excellent analgesia and muscle relaxation for orthopaedic procedures in stifle joint and structures distal to it. In six animals, nociception was noticed when the bone was drilled, or when the surgical incision was extended proximal to stifle, which could be managed by supplementing analgesic dose of ketamine (0.5 mg/kg body wt, i.v.). The protocol maintained normal mean arterial pressure, oxygenation and ventilatory status of patients. From this study it was concluded that the protocol of PS combined with femoral and sciatic nerve blocks was effective for stifle and tibial surgeries in dogs without compromising cardiopulmonary functions.