Effects of alkalinization of lidocaine on the pain of skin infiltration and intravenous catheterization

Abstract

Study Objective: To test the hypothesis that alkalinization of lidocaine decreases the pain of skin infiltration in surgical patients. Design: Double-blind, randomized, prospective study. Setting: Preoperative holding units, Brigham and Women's Hospital. Patients: 184 adult surgical patients. Interventions: We compared the efficacy of 1% lidocaine with and without 0.1 mEq/ml of sodium bicarbonate (NaHC0 3) for relief of pain of (1) skin infiltration and (2) intravenous (IV) catheterization prior to surgery. Measurements and Main Results: Patients evaluated the intensity of pain using a 100 mm visual analog scale (VAS). There were no differences between study groups (lidocaine with NaHCO 3, n = 89; lidocaine alone, n = 95) with respect to site of catheterization or catheter gauge used. Lidocaine plus NaHC0 3 caused significantly less pain on skin infiltration (median VAS = 4; range = 0 to 51) than did lidocaine alone (VAS = 8; range = 0 to 48; p < 0.008). Pain of IV catheterization also did not differ between groups. There was a weak correlation between catheter gauge and pain of IV catheterization (r = −0.19; p = 0.01). Conclusions: Pain resulting from skin infiltration of lidocaine solutions can be diminished by adding NaHC0 3 However, catheter size is more important than the presence or absence of NaHC0 3 in determining the pain of IV catheterization.