The best concentration of lidocaine for prevention of injection pain caused by propofol

Objective To observe the effect of different dosage of lidocaine for prevention of injection pain caused by propofol. Methods 200 cases of abortion were divided into four groups randomly,the L0 group was given propofol without lidocaine,the L1 group was given 10 ml of 1% propofol with 1 ml of 2% lidocaine,the L2 group was given 10 ml of 1% propofol with 1.25 ml of 2% lidocaine,the L3 group was given 10 ml of 1% propofol with 1.5 ml of 2% lidocaine, each group had 50 cases.All these patients were given the intravenous fentanyl(1.0 μg/kg) before intravenous propofol with or without lidocaine(propofol 1-2 mg/kg).The situations of injection pain in each group were observed. Results The incidence of injection pain was highest in the L0 group.Patients in the L1 group still had minor injection pain.The injection pain in the L1 and L2 group was almost disappeared and had no significant difference. Conclusion The mixture of 10 ml of 1% propofol with 1.25 ml of 2% lidocaine(0.25% lidocaine in the mixture) is the best concentration for prevention of injection pain.