Efficacy and adverse effects of patient-controlled epidural or intravenous analgesia after major surgery.

BACKGROUND: The purpose of this retrospective study was to determine whether epidural fentanyl-bupivacaine patient-controlled analgesia (PCA) was more efficacious and had fewer adverse effects than epidural or intravenous morphine PCA.

METHODS: We retrospectively retrieved data from 859 patients (mean age 64+/-7 years) who received continuous epidural medication, either morphine or fentanyl-bupivacaine PCA, or intravenous morphine PCA for postoperative pain control after major elective surgery from 1999 to 2000. Pain was assessed postoperatively using a verbal analogue pain scale (VAS, 0-10) during rest, mobilization, and coughing. Adverse effects including nausea, vomiting, pruritus, urinary retention, sedation, motor block, and respiratory depression (< 8 breaths per minute) were recorded. On the third postoperative day, the overall quality of pain control was evaluated using a pain relief scale (PRS, 1-4).

RESULTS: There were 201 patients who had epidural morphine PCA, 427 patients who had fentanyl-bupivacaine PCA, and 231 patients who had intravenous morphine PCA. Most patients (> 86%) who received epidural or intravenous PCA, either morphine or fentanyl combined with bupivacaine, experienced good pain relief (VAS, 0-3) during rest, mobilization, and coughing. Nonetheless, patients who received epidural morphine or fentanyl-bupivacaine had greater satisfaction with overall pain relief (PRS = 4) than did those who received intravenous morphine (p<0.05). Nausea and vomiting were most common in the epidural morphine group (p<0.05). Pruritus occurred least often in patients who received epidural fentanyl-bupivacaine analgesia (p < 0.05). There were no differences in other adverse events such as urinary retention, sedation, and motor block among the three groups. No respiratory depression was found in any patient.

CONCLUSIONS: Patients receiving epidural fentanyl-bupivacaine PCA experienced better overall pain relief, while morphine PCA, either epidurally or intravenously, caused more side effects. It is considered safe to use continuous epidural PCA with fentanyl-bupivacaine in patients receiving major elective surgery.