title: Alkalinization of epidural 0.5% bupivacaine for cesarean section.
abstract: Controversial results have been published in the literature concerning the efficacy of alkalinization of solutions of local anesthetics to shorten the time to onset of sensory block. Fifty-two parturients scheduled for cesarean section at term under epidural anesthesia were randomly allocated to one of four groups: group 1, 0.5% plain bupivacaine (pH = 5.38 +/- 0.05); group 2, 0.5% bupivacaine pH-adjusted with 1.4% sodium bicarbonate (pH = 6.87 +/- 0.01); group 3, 0.5% bupivacaine with 1:200,000 epinephrine (pH = 4.80 +/- 0.04); and group 4, 0.5% bupivacaine pH-adjusted with 1:200,000 epinephrine (pH = 6.68 +/- 0.01). The time to onset of the sensory block was evaluated using a nerve stimulator technique. Motor blockade was assessed using Bromage's scale. No differences in the characteristics of the onset of the sensory block were observed with epinephrine-containing solutions nor with pH-adjusted local anesthetics. The maximal degree of motor blockade was not significantly different in the four groups. We conclude that alkalinization of a 0.5% bupivacaine solution is not an effective way to shorten the latency of epidural block for cesarean section.
authors.affiliation: Department of Anesthesiology, Université Paris-Sud, Hôpital Béclère, Clamart, France.
authors.forename: D
authors.initials: D
authors.lastname: Benhamou
authors.forename: T
authors.initials: T
authors.lastname: Labaille
authors.forename: L
authors.initials: L
authors.lastname: Bonhomme
authors.forename: N
authors.initials: N
authors.lastname: Perrachon
mesh_terms: D000328:Adult; D000767:Anesthesia, Epidural; D000773:Anesthesia, Obstetrical; D001639:Bicarbonates / Q000008:administration & dosage; D002045:Bupivacaine; D002585:Cesarean Section; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011247:Pregnancy; D011930:Reaction Time; D012964:Sodium / Q000008:administration & dosage; D017693:Sodium Bicarbonate
chemical_list: D001639:Bicarbonates; D017693:Sodium Bicarbonate; D012964:Sodium; D002045:Bupivacaine