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

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. 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). 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. 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.