Ropivacaine for postoperative epidural analgesia*

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Abstract

Ropivacaine is a long-acting local anesthetic that has lower toxicity than bupivacaine and causes less motor block when given via the epidural route in low concentrations. This makes it a potentially useful drug for postoperative epidural analgesia. Studies with epidural infusions of plain ropivacaine for 24 to 72 hours have shown that a large proportion of patients (up to 50%) required supplemental analgesics or were withdrawn from the study because of inadequate analgesia. This is not surprising and is consistent with earlier experience with bupivacaine because clinical experience shows more rapid segmental regression with ropivacaine than bupivacaine; however, when combined with fentanyl (2 to 4 μg/mL), ropivacaine 0.2% provides a similar quality of analgesia to bupivacaine (0.1% to 0.2%) with fentanyl (2 to 4 μg/mL), although there are few direct comparisons. The use of patient-controlled epidural analgesia with ropivacaine also is effective provided it is combined with an opioid. Initial studies with levobupivacaine show a similar need for admixture with adjuvants (eg, fentanyl) for effective postoperative analgesia. The incidence of motor block in the lower limbs is low with thoracic epidural infusions, and no difference has been consistently shown between ropivacaine and bupivacaine. There is evidence, however, that with lumbar epidural infusions, less motor block occurs in patients receiving ropivacaine than similar concentrations of bupivacaine. Acute toxicity is highly unusual in the postoperative setting. Both ropivacaine and bupivacaine show no significant increase in free plasma levels during prolonged (up to 72 hours) epidural infusion. There is a theoretical advantage of ropivacaine, and possibly levobupivacaine, in the circumstance of massive epidural overdose because of more rapid block regression than bupivacaine and less systemic toxicity. Copyright © 2001 by W.B. Saunders Company

Section snippets

Continuous epidural analgesia

The ability of a local anesthetic to provide effective postoperative analgesia by epidural infusion is dependent on many factors apart from the nature of the drug itself. Issues, such as the vertebral level of catheter placement; mode of infusion administration (continuous infusion, intermittent boluses, or patient-administered bolus doses);and coadministration of adjuvants, make comparisons between studies difficult; however, the widespread use of epidural opioid-local anesthetic combinations

Patient-controlled epidural analgesia

Patient-controlled epidural analgesia (PCEA) is becoming more widely used for postoperative analgesia due to the potential for improved pain control because patients can quickly respond to their own needs. Having noted the increased propensity for segmental regression with continuous ropivacaine infusions, because of, in part, a more rapid offset of block compared with bupivacaine, it would seem that PCEA with ropivacaine may overcome some of the difficulties of maintaining a block and thus

Motor block

Motor block is an undesirable effect of postoperative epidural local-anesthetic infusions. The ability to mobilize and ambulate minimizes many complications of the postoperative period and maximizes compliance with physiotherapy. Laboratory and clinical studies have consistently shown that ropivacaine causes less motor fiber blockade than bupivacaine4 when given by lumbar epidural infusion. The mechanism for this is not entirely clear, although it may relate to the lower lipid solubility of

Toxicity

Local-anesthetic toxicity is an issue of continuing relevance in clinical anesthetic practice, especially with respect to rapid, accidental intravenous administration or subacute toxicity from absorption of a large perineural depot of local anesthetic. However, issues of toxicity are different in the postoperative setting. Large prospective audits of acute pain services have failed to report cases of inadvertent systemic administration of large amounts of local anesthetics. This does not mean

Conclusions

The choice of long-acting local anesthetics for postoperative epidural infusion depends on multiple factors including mode of administration, spinal level of infusion, and coadministration of other analgesics. Adjuvants, such as fentanyl, are required with all currently available local anesthetics to provide the most reliable postoperative analgesia when given via continuous epidural infusion. The advantages of lower systemic toxicity of ropivacaine are offset, to an extent, by segmental

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  • Cited by (1)

    *

    Address correspondence to David A. Scott, MB, BS, FANZCA, Department of Anaesthesia, St Vincent's Hospital, 41 Victoria Parade, Fitzroy Victoria 3065, Australia.

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