Epidural Patient-Controlled Analgesia: Influence of Bupivacaine and Hydromorphone Basal Infusion on Pain Control After Cesarean Delivery

Epidural administration of hydromorphone was evaluated using a patient-controlled analgesia (PCA) delivery system in 170 healthy women undergoing elective cesarean delivery with epidural bupivacaine who were randomly assigned to one of four epidural PCA treatment groupsgroup I, hydromorphone alone by bolus administration; group II, hydromorphone, with a continuous (basal) infusion; group III, hydromorphone in combination with 0.08% bupivacaine by bolus administration; or group IV, hydromorphone and bupivacaine, with a concurrent infusion of both drugs. Patients in group I required significantly less opioid medication (2.1 ± 1.1 mg [mean ± SD]) during the first 24 h than patients in group II (3.3 ± 1.3 mg). Similarly, patients in group III self-administered significantly less hydromorphone (2.0 ± 1.0 mg) and bupivacaine (23.3 ± 11.4 mg) during the first 24 h of PCA therapy, compared with patients in group IV (hydromorphone [2.7 ± 1.1 mg] and bupivacaine [31.5 ± 11.6 mg]). The concomitant use of a local anesthetic or basal opioid infusion with hydromorphone via epidural PCA did not decrease the number of PCA demands or delivered doses. In addition, patients in all four groups had similar pain, sedation, discomfort, fatigue, and anxiety scores. The frequency of awakening at night to self-administer analgesic medication was not decreased when a basal infusion was used. Although only 5% of patients receiving hydromorphone alone complained of nausea, 25% of the patients receiving the opioid-local anesthetic combination (group III) reported PCA-related nausea (P < 0.05). Although the overall incidence of pruritus did not differ among treatment groups (55%-72%), 42% of patients in group IV required antipruritic therapy compared with 22% in group I (P < 0.05). Minimal hemoglobin oxygen saturation values at night were 94% (±2%) in all four groups. Persistent lower extremity paresthesias were noted in 22% of patients receiving the opioid-local anesthetic infusion (group IV), with 20% requiring discontinuation of the infusion secondary to difficulty ambulating. In the opioid-local anesthetic combination (vs opioid alone) group, significantly more patients required recatheterization, owing to urinary retention. Times to recovery of bowel function, ambulation, resumption of a solid diet, discontinuation of PCA therapy, and hospital discharge were similar in all four groups. In conclusion, the efficacy of epidural PCA with hydromorphone was not improved by adding 0.08% b