Fentanyl or sufentanil continuous infusion during isoflurane anaesthesia in dogs: clinical experiences.

The intraoperative use of opioids is now routine practice as part of a balanced anaesthetic technique. Fentanyl is a well-known selective m-opioid receptor agonist and is particularly suitable as an intraoperative analgesic because of its short onset and duration (Monk et al., 1988; Mendes and Selmi, 2003). Sufentanil, another m-opioid receptor agonist, is the thienyl analogue of 4-nilinopiperidine (Mendes and Selmi, 2003; Bufalari et al., 2004). Both agents have been used for the induction and maintenance of analgesia, especially in humans (Bovill et al., 1984; Ahonen et al., 2000). To our knowledge, there are no clinical comparative reports of the infusion of fentanyl or sufentanil during isoflurane anaesthesia in dogs. The purpose of the study reported here was to determine the sedative, analgesic and cardiorespiratory effects during constant rate infusion of the two opioids during isoflurane anaesthesia in dogs undergoing orthopaedic surgery. We also aimed to investigate the propofol sparing induction dose and the quality of sedation, induction and recovery for each combination.