Effect of ovarian cycle on sedative effect of propofol

Objective To investigate the effect of ovarian cycle on the sedative effect of propofol in patients. Methods Forty ASA Ⅰ or Ⅱ patients, aged 20-40 yr, with body mass index 20-25 kg/m2 , scheduled for elective gynecologic laparoscopic surgery, were divided into 2 groups according to the progesterone level ( n = 20 each): follicular phase group (group F, serum progesterone concentration 0.31-1.52 ng/ml) and luteal phase group (group L, serum progesterone concentration 5.16-18.56 ng/ml). Anesthesia was induced with target-controlled infusion (TCI) of propofol and iv injection of fentanyl and cisatracurium. The initial target plasma concentration (Cp) of propofol was set at 2 μg/ml, after the Cp reached the predetermined level, the Cp increased by 0.5 μg/ml every 30 s until the patients lost consciousness and BIS value was decreased to 50. The BIS value and Cp of propofol was recorded when the patients lost consciousness. The Cp of propofol was also recorded when BIS value was decreased to 50. The patients were tracheal intubated and mechanically ventilated. Anesthesia was maintained with TCI of propofol combined with remifentanil. BIS value was maintained at 45-55 by adjusting the Cp of propofol. Results The Cps of propofol were significantly higher when the patients lost consciousness and when BIS value was decreased to 50 in group F than in group L ( P ＜ 0.05 or 0.01) . There was no significant difference in BIS value when the patients lost consciousness between the two groups (P ＞ 0.05). Conclusion Ovarian cycle can affect the sedative effect of propofol in patients, which shows that the sedative effect during the follicular phase is lower than that during the luteal phase. Key words: Menstrual cycle;  Propofol;  Conscious sedation