Alkalinization on Epidural 2 % Lidocaine Solution for Cesarean Section

Kim, Ae Ra; Kim, Hong Ran

Abstract

Sixty parturients scheduled for elective cesarean section at term under epidural anesthesia were randomly divided into one of two groups. Group 1 patients were given a prepared 2% lidocaine solution with 1:200,000 epinephrine plus 1ml of normal saline per 10ml of lidocaine; the solution pH was 2.45. Group 2 patients were given a prepared 2% lidocaine solution with 1:200,000 epinephrine plus 1ml(lmEq) NaHCO3 per 10ml of lidocaine; the solution pH was 7.20. Just before injection, either 2ml normal saline(group 1)or 2ml(2mEq) 8.4 % NaHCO3 solution(group 2) was added to 20ml 2% lidocaine hydrochloride with 1:200, 000 epinephrine. The time to onset of the T5 sensory block (time between completion of injection and loss of cold sensation at T5 dermatome) was significantly more rapid in the group 2 that received the pH adjusted solution. The mean onset time was 4.9+/-1.3 min in the group 2 and 6.4+/-2.0 min in the group 1. The time to peak level was also significantly more rapid in the group 2 at 10.5+/-2.7 min and group 1 at 13.3+/-4.0 min. But the peak level was not statistically signifieant between the two groups. The spread of sensory blockade was significantly more rapid in the pH-adjusted group at 5, 10 and 15 min after epi- dural injection. Incidence of maternal hypotension during the operation did not differ signifi- cantly between the two groups. The time from end of injection to Bromage scale 0 did not differ significantly between the two groups.