Preventing pain during injection of propofol: The optimal dose of lidocaine

Study Objective: To define the optimal dose of lidocaine to be added to propofol to reduce the incidence of pain during its injection. Design: Double-blind, randomized, placebo-controlled study. Setting: Medical center operating rooms. Patients: 135 ASA I and II female patients undergoing minor outpatient surgery. Interventions: Patients were randomly allocated to one of five groups: Group A (control), no lidocaine; Grout, B, lidocaine 10 mg; Group, C, lidocaine 20 mg; Group, D, lidocaine 30 mg; Group E, lidocaine 40 mg: For each patient, pain during injection of the propofol solution was graded as none, mild, moderate, or severe. Measurements and Main Results: The incidence of pain In the control group was 85%. All treatment groups receiving lidocaine had a significantly lower incidence of pain compared with the control group (p < 0.001). The lidocaine 30 mg and 40 mg groups both had a 7% incidence of pain, which was significantly less than a 33% incidence in the lidocaine 10 mg group (p < 0.05). Conclusions: Within this dose range and in this patient population, 30 mg of lidocaine is optimal for reducing the pain during injection of propofol. (C) 1996 by Elsevier Science Inc.