title: A prospective, randomized controlled trial of conscious sedation using propofol combined with inhaled nitrous oxide for dental treatment.
abstract: OBJECTIVE
  Adverse reactions during propofol sedation include a decrease in arterial blood pressure, propofol-induced pain on injection, and airway complications. The purpose of this study was to investigate whether combined use of intravenous propofol and inhaled nitrous oxide could decrease the hypotensive and other adverse effects of propofol.
  
  
  METHODS
  We designed and implemented a prospective, randomized controlled trial. Patients undergoing dental procedures requiring intravenous sedation were randomly allocated to 2 groups: group P comprised those receiving sedation with propofol alone, and group N+P comprised those receiving sedation with 40% nitrous oxide inhalation and propofol. During the dental procedures, the sedation level was maintained at an Observer's Assessment of Alertness/Sedation scale score of 4 by adjusting propofol's target plasma concentration. Nitrous oxide inhalation was the predictor variable, whereas the hemodynamic changes, amount and concentration of propofol, and adverse events were the outcome variables.
  
  
  RESULTS
  Eighty-eight patients were successfully analyzed without any complications. The total amount of propofol was significantly less in group N+P (249.8 ± 121.7 mg) than in group P (310.3 ± 122.4 mg) (P = .022), and the mean concentration of propofol was significantly less in group N+P (1.81 ± 0.34 μg/mL) than in group P (2.05 ± 0.44 μg/mL) (P = .006). The mean blood pressure reduction in group N+P (11.0 ± 8.0 mm Hg) was significantly smaller than that in group P (15.8 ± 10.2 mm Hg) (P = .034). Pain associated with the propofol injection and memory of the procedure were less in group N+P (P = .011 and P = .048, respectively). Nitrous oxide did not affect respiratory conditions or recovery characteristics.
  
  
  CONCLUSIONS
  The results of this study suggest that nitrous oxide inhalation combined with propofol sedation attenuates the hypotensive effect and pain associated with propofol injections, along with potentiating the amnesic effect.
authors.affiliation: Resident, Department of Dental Anesthesiology, Dr Yokoe is now Resident with the Department of Anesthesia, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan.
authors.forename: Chizuko
authors.initials: C
authors.lastname: Yokoe
authors.affiliation: Assistant Professor, Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Osaka, Japan. Electronic address: hanamoto@dent.osaka-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hanamoto
authors.affiliation: Associate Professor, Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Mitsutaka
authors.initials: M
authors.lastname: Sugimura
authors.affiliation: Associate Professor, Department of Dental Anesthesiology, Dr Morimoto is now Associate Professor with the Special Patient Oral Care Unit, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Morimoto
authors.affiliation: Associate Professor, Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Kudo
authors.affiliation: Professor, Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Niwa
mesh_terms: D000328:Adult; D000368:Aged; D000762:Anesthesia Recovery Period; D000766:Anesthesia, Dental / Q000379:methods*; D019162:Anesthetics, Combined / Q000008:administration & dosage*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D016292:Procedural Sedation / Q000379:methods*; D003729:Dental Care; D004569:Electroencephalography / Q000187:drug effects; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007022:Hypotension / Q000517:prevention & control; D007275:Injections, Intravenous / Q000009:adverse effects; D008568:Memory / Q000187:drug effects; D008875:Middle Aged; D009609:Nitrous Oxide / Q000008:administration & dosage; D010100:Oxygen / Q000097:blood; D010146:Pain / Q000209:etiology; D015742:Propofol / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood; D011446:Prospective Studies; D012119:Respiration / Q000187:drug effects; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D009609:Nitrous Oxide; D010100:Oxygen; D015742:Propofol