title: Increased progesterone production during the luteal phase of menstruation may decrease anesthetic requirement.
abstract: Besides having important hormonal effects, progesterone has depressant and hypnotic effects on the brain. In this study, we compared women in the follicular phase with low progesterone levels and in the luteal phase with high progesterone levels regarding their anesthetic requirements. Twenty patients with menstrual cycle days from 1 to 10 (follicular group) and 20 patients with menstrual cycle days from 18 to 24 (luteal group) were included in the study. Anesthesia was induced with fentanyl and thiopental; relaxation was secured with rocuronium, and anesthesia was maintained with a mixture of nitrous oxide 2 L/min and oxygen 2 L/min plus sevoflurane. The delivered sevoflurane concentration was adjusted to sustain a constant bispectral index value that averaged 46 in both groups. To determine the progesterone levels, blood samples were taken from all patients before surgery. We found that progesterone levels were 0.86 +/- 0.30 ng/mL in the follicular group and 7.48 +/- 3.86 ng/mL in the luteal group. The minimum alveolar anesthetic concentration (MAC)-hour (MAC-h) value of sevoflurane in the follicular group (1.55 +/- 0.18 MAC-h) was significantly larger than in the luteal group (1.3 +/- 0.13 MAC-h) (P < 0.0001). The sevoflurane requirements were larger in the follicular group during the maintenance phase of anesthesia. In conclusion, high progesterone levels during the luteal phase might be the cause of decreased anesthetic requirement.
  
  
  CONCLUSIONS
  The aim of this study was to determine the effect of high progesterone levels on anesthetic requirement. We measured progesterone levels before surgery and calculated the sevoflurane dose (MAC-h) required to maintain a constant bispectral index value. The dose of sevoflurane correlated inversely with serum progesterone concentrations.
authors.affiliation: *Departments of Anesthesiology and †Obstetrics/Gynecology, SSK Vakıf Gureba Hospital, Istanbul, Turkey.
authors.forename: Veysel
authors.initials: V
authors.lastname: Erden
authors.forename: Zehra
authors.initials: Z
authors.lastname: Yangn
authors.forename: Kerem
authors.initials: K
authors.lastname: Erkalp
authors.forename: Hamdi
authors.initials: H
authors.lastname: Delatioğlu
authors.forename: Feyza
authors.initials: F
authors.lastname: Bahçeci
authors.forename: Ayşe
authors.initials: A
authors.lastname: Seyhan
mesh_terms: D000293:Adolescent; D000328:Adult; D000777:Anesthetics / Q000008:administration & dosage* / Q000493:pharmacokinetics; D004569:Electroencephalography; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006801:Humans; D008183:Luteal Phase / Q000378:metabolism*; D011374:Progesterone / Q000096:biosynthesis*; D013874:Thiopental / Q000008:administration & dosage
chemical_list: D000777:Anesthetics; D011374:Progesterone; D013874:Thiopental; D005283:Fentanyl