title: Clinical assessment of propofol-induced yawning with heart rate variability: a pilot study.
abstract: OBJECTIVE
  To investigate the proportion of propofol-induced yawning and sympathovagal balance during propofol-induced yawning.
  
  
  METHODS
  Prospective, observational, clinical study.
  
  
  METHODS
  University hospital and 2400-bed tertiary medical center.
  
  
  METHODS
  546 ASA physical status I and II patients undergoing elective surgery with general anesthesia.
  
  
  METHODS
  Standard induction of anesthesia was performed with intravenous (IV) propofol two to four mg/kg (group P), or pretreatment with atropine 0.1 mg/kg (group AP) or with fentanyl 1 to 3 microg/kg (group FP) before propofol. Continuous standard electrocardiogram for heart rate variability (HRV) was performed in another 20 patients to investigate sympathovagal balance during propofol-induced yawning.
  
  
  RESULTS
  The proportions of yawning were 53.5% (207/386), 61.1% (55/90), and 0% (0/50) in the P, AP, and FP groups, respectively. Propofol-induced yawning could be dramatically decreased by pretreatment with IV fentanyl (P < 0.001, chi2 test). Significant increased ratio of low-frequency/high-frequency power was detected during HRV monitoring in 9 patients with yawning in comparison with 11 patients without yawning (P < 0.05, Wilcoxon signed-rank test).
  
  
  CONCLUSIONS
  Pretreatment with fentanyl may inhibit propofol-induced yawning. Fluctuations in autonomic function have been noted during propofol-induced yawning.
authors.affiliation: Department of Pulmonology, Ren-Ai Branch, Taipei City Hospital, Taipei 483, Taiwan.
authors.forename: Chih-Hsiang
authors.initials: CH
authors.lastname: Tsou
authors.forename: Tsair
authors.initials: T
authors.lastname: Kao
authors.forename: Kuo-Tung
authors.initials: KT
authors.lastname: Fan
authors.forename: Jia-Horng
authors.initials: JH
authors.lastname: Wang
authors.forename: Hsiang-Ning
authors.initials: HN
authors.lastname: Luk
authors.forename: Heidi M
authors.initials: HM
authors.lastname: Koenig
mesh_terms: D000759:Adjuvants, Anesthesia / Q000494:pharmacology; D000328:Adult; D000704:Analysis of Variance; D000768:Anesthesia, General; D018686:Anesthetics, Intravenous / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004562:Electrocardiography; D005260:Female; D005283:Fentanyl / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D015742:Propofol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011446:Prospective Studies; D015000:Yawning / Q000187:drug effects* / Q000502:physiology
chemical_list: D000759:Adjuvants, Anesthesia; D018686:Anesthetics, Intravenous; D005283:Fentanyl; D015742:Propofol