USE OF CONTINUOUS-INFUSION ALFENTANIL FOR ANALGESIA DURING SPARK-GAP LITHOTRIPSY

The painful stimuli produced by a new generation of electrohydraulic/e lectromagnetic lithotripters are such that continuous infusion analges ia rather than general or regional anesthesia is appropriate. We descr ibe our experience with continuous alfentanil infusion supplemented wi th intravenous bolus midazolam in caring for patients treated with an unmodified Medstone STS 1050 lithotripter. Ninety consecutive treatmen ts using this technique averaged 63 minutes, compared with 69 minutes for 14 treatments done with general anesthesia and 88 minutes for 58 t reatments done with epidural anesthesia. The stone burden, kilovoltage , and number of shocks were similar for the three groups, as was the i mmediate stone fragmentation rate. Only 2 of 90 patients received inad equate analgesia with the intravenous technique and required the induc tion of general anesthesia. Continuous-infusion analgesia appears suff icient to blunt the stimulus provided by the unmodified spark-gap lith otripters still in common use.