Comparison of ropivacaine with and without fentanyl vs bupivacaine with fentanyl for postoperative epidural analgesia in bilateral total knee replacement surgery.

STUDY OBJECTIVES

Pain after total knee replacement (TKR) interferes with early rehabilitation. Although the use of epidural bupivacaine in post-TKR patients is associated with effective analgesia, the associated motor blockade effect delays functional recovery. We compared analgesic efficacy and side effects of postoperative patient-controlled epidural analgesia (PCEA) with plain ropivacaine 0.1% with/without fentanyl 2.5 μg/mL vs plain bupivacaine 0.0625% with fentanyl 2.5 μg/mL in patients undergoing bilateral TKR.

DESIGN

Prospective, double-blind, randomized study.

SETTINGS

Operation room, postoperative recovery room, and intensive joint replacement unit.

PATIENTS

Ninety American Society of Anesthesiologists I to II post-TKR patients who were randomly allocated to receive postoperative PCEA with plain ropivacaine 0.1% (group 1), ropivacaine 0.1% with fentanyl 2.5 μg/mL (group 2), and plain bupivacaine 0.0625% with fentanyl 2.5 μg/mL (group 3).

INTERVENTION

Postoperatively, the PCEA settings were standardized for a basal flow of 4 mL/h, demand dose of 6 mL, and lock-out interval of 20 minutes. "Rescue" analgesia included epidural boluses (6 mL) of respective study drug over and above PCEA administration.

MEASUREMENTS

Postoperative pain profile, total PCEA drug used, heart rate, and noninvasive blood pressure, side effects, and patient satisfaction were recorded.

MAIN RESULTS

Demographic parameters, duration of surgery, and hemodynamic variables (heart rate and noninvasive blood pressure) were comparable for the 3 study groups. Pain scores and rescue drug requirements were greater in "ropivacaine-only" group. Motor blockade was greatest in "bupivacaine-fentanyl" group. Postoperatively, despite the presence of minor side effects (nausea, itching) in the "ropivacaine-fentanyl" and bupivacaine-fentanyl groups, the patients belonging to these groups were more satisfied.

CONCLUSION

After bilateral TKR, ropivacaine-fentanyl combination administered through a PCEA system resulted in "superior" analgesic efficacy, that is, pain relief without motor blockade, than "ropivacaine alone" (lesser pain relief) and bupivacaine-fentanyl (pain relief but with attendant motor blockade). Overall, the addition of fentanyl to epidural local anesthetic returned favorable postoperative analgesia profile and patient satisfaction with minor incidence of opioid-related side effects.