Lidocaine hydrochloride versus lidocaine bicarbonate for epidural anesthesia in outpatients undergoing arthroscopic surgery.

In a randomized, double-blind study, 24 patients undergoing outpatient arthroscopic knee surgery were divided into two groups. Group 1 received 2% lidocaine hydrochloride; group 2 received pH-adjusted 1.73% lidocaine made by adding 1 ml of NaHCO3 44.6 meq/L to 10 ml of 2% lidocaine hydrochloride. Epidural anesthesia was administered in the sitting position. Group 1 consisted of 12 males; group 2 consisted of 6 males and 6 females (p less than 0.01). Statistical analysis using the unpaired Student's t-test and the Mann-Whitney test found no significant differences between the two groups regarding time of onset of analgesia, degree of spread of analgesia, time to maximum motor blockade, degree of motor blockade, length of surgical procedure, total anesthesia time, regression of anesthesia, dosage of lidocaine used, and serum lidocaine levels. Intraoperative conditions were satisfactory in all cases. Postoperatively, all patients reported having experienced a satisfactory anesthetic without any complications. The authors conclude that epidural anesthesia is a satisfactory technique for outpatient arthroscopic surgery. There appears to be no advantage to adding bicarbonate to lidocaine anesthetic solutions for use in epidural anesthesia.