Eight horses under inhalant general anesthesia with isoflurane (1MAC) and continuous infusion of xylazine (0.35mg kg-1h-1) or medetomidine (3.5µg kg-1h-1) were evaluated for heart rate and rhythm, respiratory rate, arterial blood pressure, arterial blood gas analysis and temperature immediately before the beginning of the continuous infusion (T0) and in intervals of 10 minutes after the beginning of the continuous infusion (T10 to T60). Heart rate and temperature decreased and mean arterial pressure increased. PaCO2 (in GM) increased and GM showed a higher paO2 than GX. We conclude that equipotent doses of continuous infusion of medetomidine and xylazine during inhalant general anesthesia with isoflurane in horses promote slight and equivalent cardiocirculatory, respiratory, thermic and arterial blood gases changes.
medetomidine; xylazine; continuous infusion; isoflurane; equine
