title: The influence of pH-adjusted 2-chloroprocaine on the quality and duration of subsequent epidural bupivacaine analgesia during labor: a randomized, double-blind study.
abstract: A randomized, double-blind study was performed to determine whether pH-adjustment of 2-chloroprocaine hastens the onset of epidural analgesia, and improves the quality and duration of subsequent epidural bupivacaine analgesia during labor. One milliliter of either 8.4% sodium bicarbonate or normal saline was added to a 30-ml vial of 2% 2-chloroprocaine. At 0, 5, and 7 min, each patient received 2, 5, and 3 ml of 2-chloroprocaine, respectively. At 22 min, any patient who did not yet have satisfactory analgesia received an additional 5 ml of 2-chloroprocaine. At 35, and, again, at 36 min, each patient received 5 ml of 0.25% bupivacaine. The median onset of 2-chloroprocaine analgesia was slightly more rapid in the bicarbonate group than in the saline-control group (12 versus 14 min, P less than .05). Two of 31 women in the bicarbonate group, versus 10 of 31 women in the saline-control group, required an additional 5 ml of 2-chloroprocaine at 22 min to achieve satisfactory analgesia (P = .01). There was no significant difference between groups in median duration of subsequent bupivacaine analgesia (60 min in each group) or mean (+/- SD) dosage of bupivacaine during the first stage of labor (64 +/- 43 versus 72 +/- 57 mg). Also, there was no significant difference between groups in pain scores over time.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesia, University of Iowa College of Medicine, Iowa City.
authors.forename: D H
authors.initials: DH
authors.lastname: Chestnut
authors.forename: M
authors.initials: M
authors.lastname: Geiger
authors.forename: J N
authors.initials: JN
authors.lastname: Bates
authors.forename: W W
authors.initials: WW
authors.lastname: Choi
mesh_terms: D015360:Analgesia, Epidural / Q000379:methods*; D000773:Anesthesia, Obstetrical / Q000379:methods*; D000779:Anesthetics, Local; D001639:Bicarbonates; D002045:Bupivacaine; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D004347:Drug Interactions; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007743:Labor, Obstetric / Q000187:drug effects*; D011247:Pregnancy; D011343:Procaine / Q000031:analogs & derivatives*; D011897:Random Allocation; D012964:Sodium; D017693:Sodium Bicarbonate; D012965:Sodium Chloride; D012996:Solutions; D013997:Time Factors
chemical_list: D000779:Anesthetics, Local; D001639:Bicarbonates; D012996:Solutions; D012965:Sodium Chloride; D011343:Procaine; C004616:chloroprocaine; D017693:Sodium Bicarbonate; D012964:Sodium; D002045:Bupivacaine