Background and Objectives The usefulness of adding bupivacaine to an opioid administered by the epidural route is controversial. This study examines both the quality of pain relief and side effects, in particular urinary retention, during patient-controlled epidural analgesia (PCEA) with sufentanil alone or in combination with two different concentrations of bupivacaine.

Methods In a double-blind randomized study, 60 healthy young adults undergoing open knee or ankle surgery with combined spinal-epidural anesthesia received postoperative analgesia via PCEA with sufentanil alone or with 0.06% or 0.12% bupivacaine. In addition to pain scores at rest and during mobilization, bladder function was evaluated. Strict criteria were respected in scoring the occurrence of problems suggestive of urinary retention. The 24-hour analgesic consumption and the incidence of other side effects were also recorded.

Results Patients receiving bupivacaine had better pain relief than those receiving only the opioid, but this difference was more pronounced when measuring dynamic pain scores. The consumption of sufentanil was significantly higher in the group receiving the opioid alone than in the group receiving 0.06% bupivacaine. The bupivacaine dose requirements were twice as high with the 0.12% concentration. Bladder problems occurred significantly more frequently in patients treated with the highest bupivacaine concentration. Motor impairment was not a major problem.

Conclusions A 0.06% bupivacaine-sufentanil combination offered the best results in terms of analgesic quality and lower side effects, mainly micturition problems, which may be explained by the higher consumption of local anesthetic at the higher bupivacaine concentration. Analgesic quality could not be improved by increasing the bupivacaine concentration.