The optimal effective concentration of lidocaine to reduce pain on injection of propofol.
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.
Ho
C M
CM
Department of Anesthesiology, Veterans General Hospital-Taipei, Taiwan, R.O.C. hocm@ms29.hinet.net
Tsou
M Y
MY
Sun
M S
MS
Chu
C C
CC
Lee
T Y
TY
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
D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D008012:Lidocaine; D015742:Propofol