Bupivacaine 0.01% and/or epinephrine 0.5 mu g/ml improve epidural fentanylanalgesia after cesarean section

Background: The authors studied the addition of bupivacaine and epinephrine , separately and together, to epidural fentanyl to determine whether this i mproved postcesarean analgesia and reduced the incidence of side effects. Methods: After elective cesarean section, 100 parturient patients who recei ved fentanyl (3 mu g/ml) epidurally for 48 h were allocated randomly in a d ouble-blinded manner to four groups to receive, in addition to the study so lution, 0.01% bupivacaine, 0.5 mu g/ml epinephrine, both, or neither. A neu rologic assessment of breast-fed neonates was made at 2 and 48 h of Life. P lasma fentanyl concentrations were determined in a subset of patients at in tervals after treatment. Results: Patients receiving fentanyl alone made more attempts at patient-co ntrolled analgesia (P < 0.01), required a greater total dose of fentanyl (P < 0.01), reported more pain (P < 0.003) and less satisfaction (P < 0.003), and had more nausea and urinary retention (P < 0.05) than all other groups , Patients who received bupivacaine with or without epinephrine had better overall satisfaction scores than those who did not receive bupivacaine (P < 0.001), and they required less fentanyl (P < 0.02) than patients who recei ved fentanyl with only epinephrine, Motor blockade or orthostatic hypotensi on did not develop in any patient, and all patients could ambulate without difficulty. Neurobehavioral scores, which were similar among all neonates, were within the normal range. Plasma concentrations of fentanyl increased a fter epinephrine-containing solutions were discontinued. Conclusions: During the conditions of this study, the addition of epinephri ne and bupivacaine to a 3-mu g/ml epidural fentanyl solution for postcesare an section pain relief provided superior analgesia compared with fentanyl a lone or fentanyl with epinephrine, Whether increasing the concentration of fentanyl alone might improve the efficacy of fentanyl remains unclear.