title: Rapid inhalation induction with 7% sevoflurane combined with intravenous midazolam.
abstract: OBJECTIVE
  To identify an improved rapid inhalation induction (RII) technique by investigating hemodynamics and heart rate variability of induction with midazolam and RII with 7% sevoflurane in comparison with RII alone.
  
  
  METHODS
  Prospective, randomized study.
  
  
  METHODS
  Operating room of a university hospitals.
  
  
  METHODS
  40 patients scheduled for gastrectomy without complications.
  
  
  METHODS
  In the sevoflurane (Sev) group, anesthesia was induced with tidal volume breathing of 7% sevoflurane with 50% nitrous oxide (N(2)O) in oxygen (O(2)) for 3 minutes. In the midazolam-sevoflurane group (Mid-Sev) intravenous midazolam 0.1 mg/kg was given, followed by 7% sevoflurane with 50% N(2)O. In both groups, endotracheal intubation was facilitated with vecuronium 0.15 mg/kg, which was administered at loss of consciousness.
  
  
  METHODS
  Blood pressure, heart rate, heart rate variability, time to loss of response to verbal command (sleep time), rate of body movement or cough during induction, and patient satisfaction were monitored.
  
  
  RESULTS
  Blood pressure and heart rate increased significantly in the Sev group but not in the Mid-Sev group. Heart rate was significantly higher in the Sev group at 1 minute after intubation. High-frequency component (cardiac parasympathetic activity) in heart rate variability increased before intubation, with a higher value seen in the Sev group than the Mid-Sev group. The ratio of low-frequency component to high-frequency component (cardiac sympathetic activity) did not change in either group. Sleep time did not differ between the two groups. The numbers of patients with body movement and cough, and patients who were not satisfied with the induction method were, respectively, four, three, and eight in the Sev group; and one, zero, and two in the Mid-Sev group. The last value was significantly higher in the Sev group (p = 0.0285).
  
  
  CONCLUSIONS
  The addition of intravenous midazolam 0.1 mg/kg provides more stable hemodynamics, cardiac autonomic nervous system activity, and patient satisfaction in RII with 7% sevoflurane.
authors.affiliation: Surgical Center, Department of Anesthesiology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, 108-8639 Tokyo, Japan. nishiyam@ims.u-tokyo.ac.jp
authors.forename: Tomoki
authors.initials: T
authors.lastname: Nishiyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsukawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hanaoka
mesh_terms: D000328:Adult; D000368:Aged; D000769:Anesthesia, Inhalation / Q000379:methods*; D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D001794:Blood Pressure / Q000187:drug effects; D005743:Gastrectomy; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008738:Methyl Ethers / Q000008:administration & dosage*; D008874:Midazolam / Q000008:administration & dosage*; D008875:Middle Aged; D009609:Nitrous Oxide / Q000008:administration & dosage; D017060:Patient Satisfaction; D011446:Prospective Studies; D000077149:Sevoflurane; D014474:Unconsciousness
chemical_list: D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D000077149:Sevoflurane; D009609:Nitrous Oxide; D008874:Midazolam