title: Thoracic epidural bupivacaine plus sufentanil: high concentration/low volume versus low concentration/high volume.
abstract: OBJECTIVE
  To compare the postoperative analgesic and side effects of a continuous epidural infusion of bupivacaine with sufentanil: high concentration/low volume versus low concentration/high volume.
  
  
  METHODS
  In a prospective study, 30 patients scheduled for thoracic surgery had a thoracic epidural catheter inserted. Postoperative analgesia was provided by a continuous epidural infusion for 3 days. The patients were randomly divided into two groups: the low volume (LV) group (1.5 to 2 mL per hour of a combination of bupivacaine 0.5% with sufentanil 4 micrograms.mL-1) and the high volume (HV) group (6 to 8 mL per hour of a combination of bupivacaine 0.125% with sufentanil 1 microgram.mL-1).
  
  
  RESULTS
  The visual analogue scales were not different at rest or with exercise on days 1, 2, or 3. Supplemental analgesia by epidural catheter was necessary in half the patients in both groups. In two patients in the HV group and five patients in the LV group, a PaCO2 greater than mm Hg (7 kPa) was observed the first postoperative hour. Only on day 1 was the mean PaCO2 significantly increased in both groups (5.9 mm Hg [0.7] kPa in the LV group, and 6.0 mm Hg [0.4] kPa in the HV group) compared to the mean preoperative PaCO2 (5.1 mm Hg [0.5] kPa and 4.7 mm Hg [0.6] kPa). Between the groups there was no significant difference in PaCO2 at any time.
  
  
  CONCLUSIONS
  With the thoracic epidural administration of bupivacaine and sufentanil for postoperative analgesia, the total dose is more important than the concentration or the volume of the solution.
authors.affiliation: Department of Anesthesiology, St. Radboud Hospital, University of Nijmegen, The Netherlands.
authors.forename: M M
authors.initials: MM
authors.lastname: Laveaux
authors.forename: M A
authors.initials: MA
authors.lastname: Hasenbos
authors.forename: J B
authors.initials: JB
authors.lastname: Harbers
authors.forename: T
authors.initials: T
authors.lastname: Liem
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015360:Analgesia, Epidural / Q000009:adverse effects / Q000379:methods*; D002045:Bupivacaine / Q000008:administration & dosage* / Q000009:adverse effects; D002245:Carbon Dioxide / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000139:chemically induced / Q000209:etiology; D007268:Injections, Epidural; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000188:drug therapy; D010313:Partial Pressure; D017409:Sufentanil / Q000008:administration & dosage* / Q000009:adverse effects; D013903:Thoracic Surgery
chemical_list: D002245:Carbon Dioxide; D017409:Sufentanil; D002045:Bupivacaine