title: The optimal effective concentration of lidocaine to reduce pain on injection of propofol.
abstract: OBJECTIVE
  To determine the optimal concentration of lidocaine that reduces pain on injection of a propofol-lidocaine mixture.
  
  
  METHODS
  Prospective, randomized, double-blinded, clinical investigation.
  
  
  METHODS
  Medical center, university teaching hospital.
  
  
  METHODS
  240 ASA physical status I and II female outpatients, aged 21 to 65 years, undergoing dilation and curettage with propofol for anesthesia induction.
  
  
  METHODS
  Patients were randomized to one of four groups in double-blinded fashion. In Group A (control), patients were given propofol containing normal saline; in Group B, Group C, and Group D, patients received propofol containing 0.05% lidocaine (Group B), propofol containing 0.1% lidocaine (Group C), and propofol containing 0.2% lidocaine (Group D) for induction.
  
  
  RESULTS
  The incidence of pain on injection of propofol was significantly decreased in Group C and Group D (8.3% and 10.0%, respectively) in comparison to the control group (91.7%) (p < 0.001). Although the result in Group B (76.7%) was better than that in the control group, the difference was not statistically significant. No significant difference was seen between Group C and Group D.
  
  
  CONCLUSIONS
  The optimal effective concentration of lidocaine, which decreased the incidence of pain caused by propofol injection, was 0.1% in the currently studied population.
authors.affiliation: Department of Anesthesiology, Veterans General Hospital-Taipei, Taiwan, R.O.C. hocm@ms29.hinet.net
authors.forename: C M
authors.initials: CM
authors.lastname: Ho
authors.forename: M Y
authors.initials: MY
authors.lastname: Tsou
authors.forename: M S
authors.initials: MS
authors.lastname: Sun
authors.forename: C C
authors.initials: CC
authors.lastname: Chu
authors.forename: T Y
authors.initials: TY
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000009:adverse effects; D000779:Anesthetics, Local / Q000008:administration & dosage*; D004107:Dilatation and Curettage; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D015994:Incidence; D007275:Injections, Intravenous / Q000009:adverse effects; D008012:Lidocaine / Q000008:administration & dosage*; D008875:Middle Aged; D010146:Pain / Q000517:prevention & control*; D015742:Propofol / Q000008:administration & dosage* / Q000009:adverse effects; D011446:Prospective Studies
chemical_list: D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D008012:Lidocaine; D015742:Propofol