[Postoperative on-demand analgesia with buprenorphine]

Patient-controlled analgesia (PCA) was studied during the early postoperative period. Subjects were 40 ASA I-III patients recovering from elective major and minor surgery. Buprenorphine doses of 40 micrograms each were available whenever the patients felt pain relief necessary, and were delivered by a microprocessor-controlled injection pump (On-Demand Analgesia Computer). The hourly maximum dose was set at 320 micrograms with a lockout time of 1 minute. A continuous low-dose buprenorphine infusion (5 micrograms/h) was additionally administered in order to prevent catheter obstruction. The duration of the PCA period was 16.9 +/- 5.1 h (mean +/- SD). During this time, 16.1 +/- 11.3 demands per patient were recorded resulting in individual buprenorphine consumptions of 0.63 +/- 0.59 micrograms/kg/h. More buprenorphine was needed following abdominal surgery compared with orthopedic patients, although pain relief was found slightly less in the former group. Buprenorphine consumption was significantly higher in female than in male patients. Overall efficacy and patient acceptance proved to be excellent. The effectiveness of PCA was judged superior by about 93% of patients when compared with previously experienced postoperative analgesia. Side-effects (sweating, nausea, emesis) occurred in about 10% of cases but were usually of minor intensity. No circulatory or respiratory problems were observed during the PCA period.