title: Comparing the efficacy and safety of continuous epidural analgesia in abdominal and urological surgery between two opioids with different kinetic properties: morphine and sufentanyl.
abstract: BACKGROUND
  Ample evidence is now available showing the analgesic efficacy of a local anaesthetic-opioid combination to control postoperative pain. This retrospective study aimed to analyze any improvement in the ability of sufentanyl, a highly lipophilic opioid, and morphine, a poorly lipophilic opioid, to control postoperative pain at rest and in motion when combined with ropivacaine 0.2%.
  
  
  METHODS
  In this retrospective study, 171 patients who underwent major abdominal or urological surgery were evaluated. The therapeutic protocol provided for continuous epidural perfusion (5 mL/h) of ropivacaine 0.2% + morphine 0.03 mg/mL or ropivacaine 0.2% + sufentanyl 0.75 mug/mL for 48 h. Pain at rest (numeric rate scale, NRS) and in motion (NRSm) was evaluated by means of the NRS upon waking and at 3, 6, 12, 24, 36, and 48 hs, providing for the administration of a rescue dose if NRS >4. The overall analgesic effect was evaluated by comparing the area under the NRS curve (AUC) of both treatments using the Mann Whitney U test. Any differences between treatments in terms of NRS and NRSm in time were evaluated using ordinal logistic regression. To compare the frequency of patients who reported NRS >4 at least once during the follow-up period, logistic regression was used. Finally, the frequency of patients who required at least one additional drug or reported side effects was compared using Fisher's exact test.
  
  
  RESULTS
  While both groups showed a comparable overall analgesic effect, the baseline values of NRS and NRSm were lower for the sufentanyl group (P<0.001), perhaps as a result of its quicker onset due to higher lipophilicity. No statistically significant difference was observed in the frequency of patients requiring administration of an additional analgesic drug (P=0.136) or in the incidence of complications (P=0.799).
  
  
  CONCLUSIONS
  Both protocols providing a combination of a local anaesthetic and an opioid demonstrated an excellent safety and efficacy profile. The differing lipophilicity of the opioids did not cause any clinically or statistically significant differences in terms of efficacy or safety, other than a reduced onset time of sufentanyl, ensuring better pain control upon waking. We therefore believe that morphine should be the standard opioid for neuraxial use, although these results must be confirmed in the setting of a randomized controlled clinical trial.
authors.affiliation: Anesthesia and Intensive Care Service, Città di Pavia Clinic, Pavia, Italy. lorettadelvecchio@yahoo.it
authors.forename: L
authors.initials: L
authors.lastname: Delvecchio
authors.forename: S
authors.initials: S
authors.lastname: Bettinelli
authors.forename: C
authors.initials: C
authors.lastname: Klersy
authors.forename: M
authors.initials: M
authors.lastname: Allegri
authors.forename: F
authors.initials: F
authors.lastname: Cavalloro
authors.forename: A
authors.initials: A
authors.lastname: Braschi
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000368:Aged; D015360:Analgesia, Epidural / Q000379:methods*; D000701:Analgesics, Opioid / Q000493:pharmacokinetics / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D009020:Morphine / Q000493:pharmacokinetics / Q000627:therapeutic use*; D010149:Postoperative Pain / Q000517:prevention & control*; D012189:Retrospective Studies; D017409:Sufentanil / Q000493:pharmacokinetics / Q000627:therapeutic use*; D014570:Urologic Diseases / Q000601:surgery*
chemical_list: D000701:Analgesics, Opioid; D009020:Morphine; D017409:Sufentanil