Postcesarean analgesia: the efficacy of bupivacaine wound instillation with and without supplemental diclofenac.

STUDY OBJECTIVE

To assess the analgesic efficacy of diclofenac when administered as an adjuvant to bupivacaine wound instillation.

DESIGN

Prospective, randomized, double blind, placebo-controlled study.

SETTING

Large referral hospital.

PATIENTS

90 women recovering from cesarean delivery performed via a Pfannenstiel incision.

INTERVENTIONS

A standard intrathecal anesthetic was administered. On completion of surgery, a multiorifice 20-gauge epidural catheter was placed within the surgical wound. Postoperatively, the catheter was attached to a patient-controlled analgesia (PCA) device programmed to deliver 9 mL with a 60-minute lockout time and no basal infusion. In group bupivacaine-diclofenac, the PCA device delivered 0.25% bupivacaine, and 20 minutes before the end of surgery, patients received intravenous diclofenac (75 mg/100 mL saline). Thereafter, oral diclofenac (50 mg) was administered every 8 hours. In group bupivacaine-placebo, 0.25% bupivacaine and an equal volume of intravenous saline or oral placebo were administered 20 minutes before the end of surgery and every 8 hours thereafter. In group placebo-diclofenac, wound instillation was with sterile water, and 20 minutes before the end of surgery, patients received intravenous diclofenac (75 mg/100 mL saline) and thereafter oral diclofenac (50 mg) at 8-hour intervals. During the first 6 postoperative hours, a coinvestigator administered "rescue" morphine (2 mg, intravenously). Thereafter, subcutaneous morphine (0.05 mg/kg) was administered on patient request for additional analgesia.

MEASUREMENTS AND MAIN RESULTS

The number of attempts to activate the PCA device was significantly higher in group bupivacaine-placebo (39 +/- 32) when compared with group bupivacaine-diclofenac (24 +/- 28). During the first 6 postoperative hours, the number of patients requiring rescue morphine and the total rescue morphine administered were significantly different between the groups. During the subsequent 18 hours, subcutaneous morphine administration was significantly higher in group bupivacaine-placebo. Postoperative pain scores were significantly higher in group bupivacaine-placebo when compared with those recorded in groups placebo-diclofenac and bupivacaine-diclofenac. Finally, patient satisfaction was significantly lower in group bupivacaine-placebo.

CONCLUSION

In the context of this study, the bupivacaine wound instillation with adjuvant diclofenac administration is associated with similar postoperative analgesia to that induced by diclofenac alone.