ALKALINIZATION OF LIDOCAINE 2-PERCENT DOES NOT INFLUENCE THE QUALITY OF EPIDURAL-ANESTHESIA FOR ELECTIVE CESAREAN-SECTION

This double-blind randomized study compared the effects of an epidural injection of lidocaine hydrochloride 2% (HCl) (Group 1), alkalinized lidocaine 2% (1 ml NaHCO3 per 10 ml of solution) injected either immed iately (Group 2) or one hour after preparation (Group 3) in 45 parturi ents (n = 15 per group) scheduled elective Caesarean section. Each pat ient received 16 ml of one of the three solutions. The mean pH values measured just before administration with a pH-meter PHM 64 Met-rohm AG were 6.77 for the HCl lidocaine 2% solution, 7.34 for the freshly alk alinized solution and 7.35 for the solution prepared one hour before i njection. The median maximal sensory level (range) observed war; T-3 ( T-8-C-7) T-4 (T-5-C-8) and T-4 (T-6-C-6), obtained after 19 +/- 6 min, 18 +/- 8 min and 16 +/- 6 min respectively for each group. A motor bl ock of grade 2 or 3 on the Bromage scale was obtained in 11, 10 and 14 patients respectively. No failure was observed although 3, 5, and 2 p atients in Groups 1, 2, and 3 respectively required a supplementary bo lus 20 min after the initial injection because of inadequate sensory l evel or pain at the operative site. In conclusion, this study shows th at neither fresh alkalinization of 2% lidocaine nor the delay of one h our between preparation and injection of the alkalinized solution infl uences the onset or quality of epidural anaesthesia for elective Caesa rean section.