Sevoflurane cardiocirculatory study in dogs with different oxygen and nitrous oxide concentrations

Thirty healthy, mongrel dogs, premedicated with levomepromazine (0.5mg/kg) and induced with tiopental sodium were anesthetized for 60 minutes as follow:group 1 (G1) sevoflurane in oxygen 100%; group 2 (G2) sevoflurane in nitrous oxide and oxygen 50% each and group 3 (G3) sevoflurane in oxygen 27% and nitrous oxide 63%. Heart rate increased significantly after induction (P<0.05), maintaining higher than baseline values in all groups. Mean and systolic arterial pressures decreased (P<0.05) along the time but the mean blood pressure variation was different between groups (G1<G2<C3). Diastolic blood pressure also decreased significantly after induction (P<0.05) maintaining higher than baseline values in all groups. Sevoflurane should be a good agent for the anesthesia maintenance in dogs, with minimal cardiocirculatory effects and, at 63% nitrous oxide concentration, the anesthetical requirement decrease significantly.