[Ketorolac and butylscopolamine in combination with alfentanil for renal lithotripsy]

Patient-controlled analgesia (PCA) using intravenous alfentanil provides adequate pain relief during extracorporal shock wave lithotripsy (ESWL) of renal stones. Occasional disadvantages of opioid analgesia include nausea, sedation and respiratory depression. This double-blind, placebo-controlled study examined whether the alfentanil requirements and thereby the frequency of side effects could be reduced by preemptive analgesia with the non-opioid analgesic ketorolac or the spasmolytic butylscopolamine.

90 patients scheduled for ESWL of renal stones received 1 hour prior to ESWL ketorolac 30 mg, butylscopolamine 20 mg or placebo intramusculary. 10 mg of metoclopramide and 6.6 microg/kg of alfentanil were given intravenously at the beginning of ESWL (Philips/Dornier MFL 5000). Intravenous PCA was started (demand dose: 0.25 mg of alfentanil, lockout time: 1 minute). Pain intensity (NRS 0-100), sedation score (VRS 0-4), respiratory rate (min(-1)) and partial oxygen saturation (SO(2)) were measured every 5 minutes. Statistical analysis included ANOVA and Chi-square-test (p<0,05).

Demographic and ESWL data were comparable between the study groups. However, patients of the ketorolac group were statistically significantly younger than those in the other groups. Alfentanil doses, pain scores and frequency of respiratory depression, sedation and nausea were lower subsequent to ketorolac than subsequent to butylscopolamine or placebo (not statistically significant). Signs of respiratory depression were only seen during ESWL.

The present study confirms that PCA using alfentanil is effective during ESWL of renal stones. However, because of the possibility of respiratory depression, adequate monitoring is mandatory. Preemptive analgesia with 30 mg of ketorolac or 20 mg of butylscopolamine cannot reduce alfentanil requirements or improve efficacy and safety.