Masui. The Japanese journal of anesthesiology
-
Randomized Controlled Trial Clinical Trial
[Changes in circulation and end-tidal sevoflurane concentration during infusion of sevoflurane into vaporizer].
We observed the changes in circulation and endtidal sevoflurane concentration during the infusion of the anesthetic into a vaporizer, and investigated some techniques to prevent these changes during general anesthesia. The patients were randomly divided into three groups: conventional, high concentration (conc.) and low flow groups. Inspiratory concentration of sevoflurane was kept at 1.0% and the duration of the pause in sevoflurane supply was 90 sec. ⋯ An increase in blood pressure and a tendency towards tachycardia were observed in the conventional group, and the circulation was kept constant best in the low flow group. The lowest concentrations of sevoflurane during the pause were 0.46, 0.46 and 0.93% in the conventional, high conc., and low flow groups, respectively, and exposure to high concentration of the anesthetic could not prevent the decrease. These results indicate that low flow anesthesia is a useful technique to prevent undesirable changes in circulation and anesthetic concentration.