title: The effect of pH-adjusted 2-chloroprocaine on the onset of epidural analgesia in pregnant patients in the lying and sitting position during the first stage of labor.
abstract: The purpose of this prospective, randomized, double-blind study was to compare the epidural onset time of 2% 2-chloroprocaine with pH-adjusted 2-chloroprocaine administered in either the sitting or supine position in pregnant patients during the first stage of labor. Patients in Groups I and III received the control solution in the sitting and supine position, respectively. Patients in Groups II and IV received the buffered solution in the sitting and supine position, respectively. The pH and pCO2 of the control and buffered solutions differed significantly. The pH and pCO2 of the control and buffered solutions were 4.38 +/- 0.01, 18.4 +/- 2.2 mm Hg and 7.70 +/- 0.04, 114.9 +/- 3.0 mmHg, respectively. A statistically significant reduction in the time of onset of analgesia in the pH-adjusted groups was noted. Groups I and II had onset times of 4 +/- 1.2 and 4.3 +/- 1.0, whereas Groups II and IV had onset times of 2.6 +/- 0.9 and 2.7 +/- 0.6 min., respectively. There were no intergroup differences in the cephalad spread of analgesia or duration of analgesia. Position had no effect on the onset of analgesia at the S2-3 dermatomes nor on the bilateral cephalad spread of the epidural study solutions. Our results indicate that a pregnant patient may be dosed in the lateral supine position without adversely affecting the caudad or cephalad spread of plain or pH-adjusted 2% 2-chloroprocaine, which is clinically important because the incidence of aortocaval compression is increased in the supine position when compared with the lateral supine position.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesia, University of Cincinnati College of Medicine, OH 45267-0531.
authors.forename: W E
authors.initials: WE
authors.lastname: Ackerman
authors.forename: M M
authors.initials: MM
authors.lastname: Juneja
authors.forename: D M
authors.initials: DM
authors.lastname: Kaczorowski
authors.forename: S M
authors.initials: SM
authors.lastname: Sarracino
authors.forename: D D
authors.initials: DD
authors.lastname: Denson
authors.forename: C J
authors.initials: CJ
authors.lastname: Nicholson
authors.forename: J
authors.initials: J
authors.lastname: Schipper
mesh_terms: D000328:Adult; D015360:Analgesia, Epidural; D000779:Anesthetics, Local / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007747:Labor Stage, First / Q000187:drug effects*; D007743:Labor, Obstetric / Q000187:drug effects*; D011187:Posture; D011247:Pregnancy; D011343:Procaine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic
chemical_list: D000779:Anesthetics, Local; D011343:Procaine; C004616:chloroprocaine