The evaluation of the effects of nitrous oxide on cardiovascular system and hemodynamic parameters in dogs undergoing low-flow sevoflurane anesthesia

In this study, it was aimed to evaluate the effect of nitrous oxide use on cardiovascular, ventilation and blood gas parameters in dogs under low-flow sevoflurane anesthesia and to determine its clinical usability in line with the data obtained. The study material consisted of 20 dogs brought to Surgery Clinic of Burdur Mehmet Akif Ersoy University, Faculty of Veterinary Medicine with different complaints. Dogs were randomly divided into two equal groups (low flow anesthesia with N2O n=10, low flow anesthesia whitout N2O n=10). For premedication, 1 mg/kg diazepam and 1 mg/kg morphine were administered to animals in both groups. Before intubation, preoxygenation was given to both groups with 100 ml/kg/min % 100 oxygen for 2 minutes. Then, 3-4 mg/kg propofol was administered for induction and intubation was achieved. Sevoflurane at a minimal alveolar concentration of % 2.9 was used as a volatile anesthetic agent in general anesthesia. The gas flow was set to 50 % oxygen and 50% nitrous oxide for the nitrus oxide group, and 100 % oxygen for the other group. In both groups, in the first 10 minutes of intubation, 100 ml/kg/min normal flow was applied, and then 14 ml/kg/min low flow was started. 10 minutes before the end of the operation, the vaporizer was turned off in both groups and normal flow was resumed, while nitrous oxide was turned off for the group with nitrous oxide. Cardiovascular parameters and ventilation parameters were recorded at five minute intervals during anesthesia, and venous blood gas analysis was performed before anesthesia, 30 minutes after anesthesia, and 10 minutes after the voparizer was turned off. As a result of the data recorded every five minutes during the anesthesia, the pulse and NIBP values of the subjects were found to be within the normal range, and hypotension was not observed in any of the subjects. When the SpO2, EtCO2 and blood gas values of the cases were examined, it was observed that hypoxia did not occur in both groups. The difference between the MAC value of sevoflurane in the 1st and 2nd groups was found to be statistically significant, and the MAC value of sevoflurane was found to be higher in the N2O group. Similar results were obtained in cardiovascular and ventilation parameters and venous blood gas analyzes for both groups. As a result, it was concluded that it is not necessary to use N2O in low flow anesthesia, which is determined to be quite advantageous in general anesthesia of dogs, provided that appropriate conditions are suplied..