Inhalatory anesthesia is considered very safe for most veterinary patients. However, there are several clinical situations in which a feasible protocol of intravenous anesthesia is demanded. As it still lacks data concerning total intravenous anesthesia in dogs, this study was conceived to evaluate the occurrence of adverse reactions in dogs submitted to anesthesia with continuous infusion of propofol and sufentanil for 120 minutes.

For such, twelve female mongrel healthy dogs were used, with mean weight of 18.21±2.81 kg. Dogs were given acepromazine (0.05 mg/kg IV) and induced with propofol (5 mg/kg IV) following an alimentary and hydric fast of 12 and 2 hours, respectively. Anesthetic maintenance was done with continuous infusion of propofol (0.2 mg/kg/minute), associated to three different doses of sufentanil, accordingly to the experimental group in which the dog was allocated: (A) 0.25 µg/kg/minute; (B) 0.5 µg/kg/minute and (C) 0.75 µg/kg/minute. Each dog was anesthetized three times, being once with each dose.

For group (A), it was seen the occurrence of four adverse reactions (33.3%), of which two happened on induction, one on maintenance and one on recovery. All reactions were characterized by muscular contractions and spastic shivering on thoracic limbs. For group (B), it was observed five adverse reactions (41.7%), of which one happened during induction and was characterized by spastic muscular shivering. During maintenance, it was also seen one occurrence of spastic muscular shivering, which was associated to paddling. Nevertheless, on recovery, three reactions were observed, which included paddling and spastic muscular contractions. For group (C), three adverse reactions (25.0%) were verified. It was observed spastic muscular contractions associated to paddling in one dog during maintenance and in two animals during recovery. Data was submitted to Kruskal-Wallis statistical test, which showed no significant differences between groups (P=0.7165).

Results allowed concluding that the absence of severe adverse reactions during this anesthetic protocol makes it safe and feasible for use in dogs. Moreover, it was seen no increase in the number or in severity of adverse reactions accordingly to the increase of sufentanil dose.