Reduction in injection pain using buffered lidocaine as a local anesthetic before cardiac catheterization

Previous reports have suggested that pain associated with the injection of lidocaine is related to the acidic pH of the solution. To determine if the addition of a buffering solution to adjust the pH of lidocaine into the physiologic range would reduce pain during injection, we performed a blinded randomized study in patients undergoing cardiac catheterization. Twenty patients were asked to quantify the severity of pain after receiving standard lidocaine in one femoral area and buffered lidocaine in the opposite femoral area. The mean pain score for buffered lidocaine was significantly lower than the mean score for standard lidocaine (2.7 +/- 1.9 vs. 3.8 +/- 2.2, P = 0.03). The pH adjustment of standard lidocaine can be accomplished easily in the catheterization laboratory before injection and results in a reduction of the pain occurring during the infiltration of tissues.