title: The effects of hormonal status on upper airway patency in normal female subjects during propofol anesthesia.
abstract: OBJECTIVE
  To determine the mechanical upper airway properties and compensatory neuromuscular responses to obstruction during propofol anesthesia in the follicular and luteal phases of the menstrual cycle.
  
  
  METHODS
  Prospective, randomized study.
  
  
  METHODS
  University-affiliated hospital.
  
  
  METHODS
  12 premenopausal female volunteers for studies of upper airway collapse throughout their menstrual cycle during the follicular phase (6 -10 days) and mid-late luteal phase (20 - 24 days).
  
  
  METHODS
  The level of propofol anesthesia (1.5 - 2.0 μg/mL) required to suppress arousal responses was determined by Observer's Assessment of Alertness/Sedation scoring (level 2) and confirmed by bispectral index monitoring. Pressure-flow relationships were constructed to evaluate collapsibility (P(CRIT)) and up-stream resistance (R(US)) during acute [Passive; hypotonic electromyography (EMG)] and sustained (Active; elevated EMG) changes in nasal mask pressure. The difference between passive P(CRIT) and active P(CRIT) (ΔP(CRIT A-P)) represented the magnitude of the compensatory response to obstruction.
  
  
  RESULTS
  Passive P(CRIT) was significantly higher in the mid-late luteal phase (-4.7 cm H(2)O) than in the follicular phase (-6.2 cmH(2)O; P < 0.05). Active P(CRIT) significantly decreased compared with passive P(CRIT) in the follicular phase (-10.1 cm H(2)O) and in the mid-late luteal phase (-7.7 cm H(2)O) and (P < 0.05). No significant difference was noted in ΔP(CRIT) between the follicular (3.9 ± 2.9 cm H(2)O) and mid-late luteal phases (3.0 ± 2.6 cm H(2)O). No differences were seen in R(US) between the menstrual phases for either the passive (P = 0.8) or active (P = 0.75) states.
  
  
  CONCLUSIONS
  Menstrual phase has an effect on anatomical alterations (mechanical properties) in the hypotonic upper airway during propofol anesthesia.
authors: Department of Clinical Physiology, Nagasaki University Graduate School of Biomedical Science, Nagasaki, 852-8588, Japan.
authors: Yuko
authors: Y
authors: Hoshino
authors: Takao
authors: T
authors: Ayuse
authors: Masato
authors: M
authors: Kobayashi
authors: Shinji
authors: S
authors: Kurata
authors: Mari
authors: M
authors: Kawai
authors: Hartmut
authors: H
authors: Schneider
authors: Susheel P
authors: SP
authors: Patil
authors: Alan R
authors: AR
authors: Schwartz
authors: Jason P
authors: JP
authors: Kirkness
authors: Kumiko
authors: K
authors: Oi
mesh_terms: D000328:Adult; D000402:Airway Obstruction / Q000209:etiology*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000494:pharmacology; D056805:Consciousness Monitors; D004576:Electromyography; D005260:Female; D005498:Follicular Phase / Q000502:physiology*; D006785:Hospitals, University; D006801:Humans; D008183:Luteal Phase / Q000502:physiology*; D015742:Propofol / Q000008:administration & dosage / Q000494:pharmacology*; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol