Postoperative intrathecal patient-controlled analgesia with bupivacaine, sufentanil or a mixture of both.

In a randomised double-blind study, 45 patients, scheduled for major orthopaedic surgery under continuous spinal anaesthesia, received for relief of postoperative pain patient-controlled analgesia with either sufentanil 2 micrograms.ml-1, bupivacaine 0.0625% or a mixture of both by the intrathecal route. The mean (SD) consumption of sufentanil and bupivacaine during the first 12 h was 65.5 (27.1) micrograms and 18.2 (4.8) mg, respectively. Combining bupivacaine and sufentanil reduced the consumption of both to approximately 40% as compared to the administration of each component separately. Pain relief was very good in all subjects, although this was obtained faster with the combined regimen. Moreover, more patients in this group remained completely painfree during the entire observation period (p < 0.05). The incidence of hypotension was low and not significantly different when the plain bupivacaine group was compared with the two other groups. Nausea and vomiting were significantly more frequently observed in both groups treated with sufentanil. Motor block was not a major problem and was noticed during the first 2 h of treatment only. Tachyphylaxis did not occur. It was concluded that the groups receiving plain bupivacaine and sufentanil alone experienced pain relief of good quality. The use of a mixture, however, accelerated the onset of analgesia, improved the analgesic quality and reduced the doses for both components by 60% but at the expense of a higher incidence of nausea and vomiting.