Epidural opioid delivery methods: bolus, continuous infusion, and patient-controlled epidural analgesia.

Multiple methods of delivery of epidural opioids are acceptable, including bolus injection, continuous infusion, and patient-controlled infusion. The incidence of side effects appears to be reduced with the use of continuous infusion techniques, especially with the liquid-soluble opioids, although these appear to be most effective when infused near the center of the dermatomal pain site. with more distant catheters, the water-soluble opioids are more effective, but there use is associated with more frequent side effects. The lowest dose requirement appears to be associated with PCEA, but further study is needed to confirm the theoretical safety and efficacy of this modality, especially if a constant background infusion is used along with the PCEA. At present, significant advantages appear to be obtainable by adding local anesthetic to the opioid infusion, but the ideal drug and dosage are yet to be determined.