title: Effects of epinephrine and clonidine on plasma concentrations of spinal bupivacaine.
abstract: ASA II-III patients, scheduled for peripheral vascular surgery, were included in a study designed to assess the effect of spinal epinephrine and clonidine on plasma concentrations of spinally administered 0.5% glucose-free bupivacaine. Patients were allocated randomly to three groups to receive via a spinal catheter 22.5 mg (4.5 ml) of bupivacaine alone (Group B, 9 patients) or combined with 0.3 mg epinephrine (Group BE, 10 patients) or 0.15 mg clonidine (Group BC, 10 patients). Sensory blockade was assessed by pin-prick and motor blockade on the Bromage scale. Bupivacaine plasma concentrations were measured by gas chromatography. A trend to prolongation of local anaesthetic blockade was documented in patients receiving bupivacaine plus epinephrine or clonidine. (Time to regression of sensory blockade to L2: 170 +/- 75 min in Group B, 230 +/- 50 min in Group BE, 232 +/- 64 min in Group BC.) The maximum peak concentration (Cmax), the time to reach Cmax (Tmax) and the time-concentration curve from 0-180 min (AUC) were not different for the three groups (Cmax 228 +/- 112 ng.ml-1 in Group B, 215 +/- 103 ng.ml-1 in Group BE, 234 +/- 159 ng.ml-1 in Group BC; Tmax 41 +/- 34 min in Group B, 59 +/- 31 min in Group BE, 68 +/- 32 min in Group BC; AUC 31.0 +/- 1.7 mg.ml-1.min-1 in Group B, 27.3 +/- 1.1 mg.ml-1.min-1 in Group BE, 27.0 +/- 1.1 mg.ml-1.min-1 in Group BC). The results of this study suggest that epinephrine and clonidine do not decrease blood resorption of spinal bupivacaine.
authors.affiliation: Department of Anesthesiology, Hôpital H. Mondor, Creteil, France.
authors.forename: O
authors.initials: O
authors.lastname: Boico
authors.forename: F
authors.initials: F
authors.lastname: Bonnet
authors.forename: J X
authors.initials: JX
authors.lastname: Mazoit
mesh_terms: D000368:Aged; D000775:Anesthesia, Spinal; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology*; D003000:Clonidine / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D004837:Epinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D009475:Neurons, Afferent; D013997:Time Factors
chemical_list: D008012:Lidocaine; D003000:Clonidine; D002045:Bupivacaine; D004837:Epinephrine