Patient controlled analgesia with fentanyl or sufentanil in the postoperative period of knee ligament reconstruction: comparative study

Epidural opioids, associated or not to local anesthetics, have been used for postoperative analgesia in continuous infusion and/or patient controlled boluses. The aim of this study was to compare postoperative analgesia provided by epidural fentanyl or sufentanil, in bolus or continuous infusion, in patients submitted to knee ligament reconstruction. Seventy ASA I - II patients, aged 16 to 47 years, were randomly distributed in two groups. All patients were submitted to epidural anesthesia with 0.5% bupivacaine (100 mg) with epinephrine 1:200,000 associated to fentanyl (100 mg). At the end of the procedure, patients received epidural fentanyl (Group F) or sufentanil (Group S) in continuous infusion plus patient controlled boluses. Group F infusion solution was made of saline (85 ml), 500 microg fentanyl (10 ml) and 0.5% bupivacaine (5 ml). Group S solution was made of saline (92 ml), 150 microg sufentanil (3 ml) and 0.5% plain bupivacaine (5 ml). Infusion pump's flow was initially programmed to 5 ml h(-1), with 2 ml patient controlled bolus doses every 15 minutes at most, for both groups. The following parameters were compared: pain, number of patient controlled boluses, opioid consumption, motor block, sedation and side-effects. There have been no statistically significant difference in analgesia quality between groups, being in most cases rated good (AVS 0 to 2). There has been a significant difference in the number of patient controlled boluses, with Group F needing more boluses than Group S. There has been no difference in total infused solution volume and total infusion time. There has been no motor block after beginning of patient-controlled analgesia. Vomiting and urine retention incidences were higher in Group S and there have been no significant differences in sedation and pruritus between groups. Epidural fentanyl or sufentanil in continuous epidural infusion and patient-controlled boluses in the doses used in this study have induced excellent postoperative analgesia. However, sufentanil caused more severe side effects than fentanyl.