The prophylactic effect of lidocaine in different concentrations on propofol-induced injection pain

Objective To study the prophylactic effect of lidocaine in different concentrations added to propofol on the propofol-induced injection pain.Methods A total of 250 ASA Ⅰ-Ⅲ patients scheduled to undergo elective surgery,were randomly assigned into five groups(n=50 each).Group A received propofol without lidocaine;group B received propofol with lidocaine 0.5 mg/ml;group C received propofol with lidocaine 1 mg/ml;group D received propofol with lidocaine 2 mg/ml;group E was pretreated with lidocaine 40 mg intravenously before propofol injection.The severity of pain when injecting propofol was assessed and recorded.Results The incidence of propofol injection pain in group A was significantly higherthan those in the other groups(P0.01).Propofol injection pain was not observed in group D.Conclusion Lidocaine added to propofol injection can effectively suppress or attenuate the propofol-induced injection pain and lidocaine 2 mg/ml can completely block the pain without affecting propofol anesthesia.