G. Gaggero et al., ALKALINIZATION OF LIDOCAINE 2-PERCENT DOES NOT INFLUENCE THE QUALITY OF EPIDURAL-ANESTHESIA FOR ELECTIVE CESAREAN-SECTION, Canadian journal of anaesthesia, 42(12), 1995, pp. 1080-1084
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.