Remifentanil as a single drug for extracorporeal shock wave lithotripsy: a comparison of infusion doses in terms of analgesic potency and side effects.

UNLABELLED

This randomized, double-blind study was designed to evaluate analgesic effectiveness and side effects of two remifentanil infusion rates in patients undergoing extracorporeal shock wave lithotripsy (ESWL) for renal stones. We included 200 patients who were administered remifentanil either 0.05 microg x kg(-1) x min(-1) (n = 100) or 0.1 microg x kg(-1) x min(-1) (n = 100) plus demand bolus of 10 microg of remifentanil via a patient-controlled analgesia (PCA) device. No other sedating drugs were given. The frequencies of PCA demands and deliveries were recorded. Arterial blood pressure, oxygen saturation, and respiratory rate were recorded throughout the procedure; postoperative nausea and vomiting (PONV), dizziness, itching, agitation, and respiratory depression were measured posttreatment. Visual analog scale (VAS) scores were taken preoperatively, directly postoperatively, and 30 min after finishing the procedure. There were no statistically significant differences in the frequency of PCA demands and delivered boluses or among perioperative VAS scores. The extent of PONV and frequency of dizziness and itching immediately after and dizziness 30 min after the end of treatment were significantly reduced in the smaller dose group. We conclude that a remifentanil regimen of 0.05 microg x kg(-1) x min(-1) plus 10 microg demands is superior to 0.1 microg x kg(-1) x min(-1) plus demands, as there was no difference in the VAS scores recorded between groups and it has a less frequent incidence of side effects in patients receiving ESWL.

IMPLICATIONS

Remifentanil is an appropriate analgesic choice for patients undergoing extracorporeal shock wave lithotripsy (ESWL) therapy, as it has both fast onset and offset times. We studied remifentanil as a sole drug for ESWL and have shown that an infusion rate of 0.05 microg x kg-1 x min-1 plus patient-controlled analgesia demands of 10 microg provides adequate analgesia and has significantly less side effects than a dose of 0.1 microg x kg-1 x min-1 plus 10 microg demands.