LUMBAR EPIDURAL ANALGESIA POST-THORACIC SURGERY

Epidural analgesia following upper abdominal surgery: United Kingdom practice

BACKGROUND

Epidural Analgesia (EA) may be used to provide pain relief after upper abdominal surgery. A variety of drugs and combinations may be used. Potential side effects lead some to believe EA should be restricted to high care areas.

METHOD

The use of EA following upper abdominal surgery is surveyed in 214 hospitals in the United Kingdom by means of a postal questionnaire.

RESULTS

Sixty-seven percent use EA frequently and 3% not at all. The low thoracic site is the most commonly used, by 65%. Forty-eight percent use a combination of sites. EA is most frequently achieved using a mixture of an opioid and a local anaesthetic (97%). No other agents are used. Fentanyl and diamorphine are the opioids used most widely (61% and 52% departments, respectively) in combination with local anaesthetic. Subcutaneous heparin is regularly used in 89% of departments. In 43%, the epidural is sited shortly after administering heparin. Use of EA is restricted solely to intensive or high-care units in 46% of hospitals. In 82% of departments, EA is continued for up to 72 h. Ninety-six percent of departments use continuous epidural infusions in the post-operative period. Adjunct analgesia includes non-steroidal anti-inflammatory drugs in 50% of departments. An anaesthetist supervises EA in 89% of hospitals. EA is considered to be the best mode of analgesia available by 80% of respondents.

CONCLUSION

EA is widely used in the United Kingdom following upper abdominal surgery. A degree of consensus exists on the choice of drug types, their method of administration and duration. There is no consensus as to whether the technique should be used on a general ward, which opioid should be used or the timing of heparin.

Spinal sufentanil in rats: Part III: Effect of diluent volume on epidural sufentanil

Male Wistar rats were injected epidurally with various doses of sufentanil in 3 different dilution volumes, in order to determine differences in the lowest ED50 values for analgesia and side-effects. The lowest ED50 for both a TWR latency greater than 6 and greater than or equal to 10 s was significantly lower in the 20-microliters group as compared to the 2-microliters group. With an injection of 5 microliters, intermediate values were obtained. With regard to the side-effects, there was a trend towards increased systemic resorption with larger diluent volumes in spite of a better and more selective spinal effect, as evidenced by increasing specificity ratios. In terms of duration of analgesia at fixed doses of sufentanil, different results were obtained. At low doses of sufentanil, a pronounced diluent volume effect was present and the duration of analgesia increased as a function of the volume. At higher doses of sufentanil, however, the volume effect faded away and no differences were observed as a function of the diluent.

Respiratory depression and spinal opioids

Administration of epidural and intrathecal opioids may provide excellent postoperative analgesia, but a minority of patients will suffer dangerous respiratory depression. This review discusses the detection and measurement of respiratory depression and summarizes the relevant literature as it pertains to epidural and intrathecal opioid administration. The respiratory depressant effects and pharmacokinetics of spinal opioids are reviewed. The clinical implications and areas of future investigation are discussed.