The effect of sevoflurane on propofol with closed-loop target controlled infusion anesthesia system

Objective The primary goal was to determine the influence of sevoflurane on propofol with closed-loop target controlled infusion(TCI) delivery system in combined intravenous-inhalation anesthesia. Methods Sixty patients with ASA Ⅰ or Ⅱ were enrolled in this double-blinded study and randomly devided into three groups using the random number table method: group A, in which patients were only administrated propofol, group B and C, in which patients were given propofol for 20 min, followed with 0.6 MAC or 0.8 MAC sevoflurane for 40 min, respectively and the inhalation concentration was adjusted according to MAC. Serum propofol concentration was monitored continuouslyin. Results There was no difference in BIS among three groups (P>0.05). Serum concentration of propofol in group B and group C decreased constantly after the inhalation of sevoflurane but increased slowly when the inhalation was terminated(P<0.05), while it remained unchanged in group A. Compared with group A[(2.53±0.55), (2.54±0.61) mg/L], the decline of serum concentration was more evident in group C[(1.81±0.63), (1.24±0.4) mg/L] than group B[(1.92±0.58), (1.67±0.64) mg/L] at 30 min and 40 min during the surgery. The changing rate in group C was higher than that of group B and became stable 40 min after the stop point of propofol. Conclusions The administration of propofol with closed-loop anesthesia delivery system could adjust the anesthesia depth automatically and effectively, when the sevoflurane was inhaled with the MAC under 0.8. Key words: Sevoflurane; Propofol; Blood drug level; Closed-loop anesthesia delivery system