Alkalinizing local anesthetic does not decrease pain during injection for dorsal penile nerve block

Study Objective: To evaluate whether alkalizing local anesthetic with sodiu m bicarbonate reduces pain related to infiltration of local anesthetic duri ng dorsal penile nerve block for circumcision. Design: Prospective, randomized, double-blind, controlled study. Setting: E. Wolfson Medical Center, Holon, Israel. Patients: 144 patients aged 15 to 54 years (mean +/- SD = 22.7 +/- 8.8 year s), randomized before the block into four groups of 36 patients each. Interventions: Group A (control) received a standard solution of 1 mg/kg li docaine 2% mixed with 0.5 mg/kg bupivacaine 0.5% without epinephrine (pH = 6.3). Patients in Group B, Group C, and Group D received this mixture added with 8.4% sodium bicarbonate for a mean final pH of 6.90, 7.16, and 7.43%, respectively. Penile block was performed using a 23-gauge needle by an ane sthetist who was blinded to the pH of the solution. Measurements and Main Results: Patients were questioned regarding pain suff ered during injection of the anesthetic solutions by another physician who also was blinded to the drug used. Pain was rated by a previously repented subjective pain scale. Mean pain scales were 2.0 +/- 0.17, 2.3 +/- 0.15, 2. 2 +/- 0.16, and 1.94 +/- 0.15 for Groups A to D, respectively. The differen ces between these results were not statistically significant. Conclusion: Alkalinizing the acidic local anesthetic solution by sodium bic arbonate does not den ease pain related to infiltration during penile nerve block for circumcision. (C) 1999 by Elsevier Science Inc.