Use of a continuous alfentanil infusion for extracorporeal shock wave lithotripsy in the treatment of renal calculi.

Abstract

Extracorporeal shock wave lithotripsy (ESWL) is the most widely used treatment for renal calculi. Newer second generation lithotripters are being produced, which are considered to be less painful than their prototypes. Thus, the trend in anesthesia for ESWL is away from general endotracheal and regional anesthesia and toward less involved and more easily monitored techniques such as intravenous analgesia (IVA). This report relates our experience with a continuous alfentanil infusion for ESWL treatment of renal calculi with a nonimmersion second generation Dornier HM-4 lithotripter model. Thirty-five patients treated pre-operatively with droperidol and midazolam, followed by a continuous infusion of alfentanil, reported excellent pain relief via a numerical pain score and manifested little, if any, hypertension or tachycardia. Stone fragmentation, fluoroscopy, and recovery time did not differ between patients receiving IVA or general anesthesia. Potential disadvantages of IVA include elevation of transcutaneous CO 2, bradycardia in 14 patients requiring the use of atropine, slightly longer ESWL time, increased number of shocks needed for fragmentation, and a small failure rate, with 11% of patients requiring general anesthesia. With proper patient selection and respiratory monitoring, IVA is highly recommended for ESWL in the treatment of renal calculi.