[Opioid analgesia during extracorporeal shockwave lithotripsy of gallstones]

Gallstone lithotripsy is a new and noninvasive therapeutic option for approximately 20% of patients who harbor cholesterol gallstones. Technologically advanced second-generation lithotripters such as the Dornier MPL 9000 device have greatly simplified biliary lithotripsy with a consecutive reduction in anesthetic requirements. Despite these technical improvements, patients still can experience considerable pain and discomfort during biliary ESWL. Due to its relatively predictable pharmacokinetic profile and its short duration of action, alfentanil appeared to be a suitable drug for pain relief during stone fragmentation. In order to analyze the degree and distribution of pain during gallstone lithotripsy and to evaluate pain control by alfentanil, 44 consecutive patients (ASA I-II) with no previous ESWL therapy were studied. Pain intensity and degree of opioid-induced sedation during shock wave application were evaluated according to 5-point verbal scales that ranged from 0 = no pain to 4 = unbearable pain and 0 = patient awake to 4 = patient asleep. All patients were treated while in the prone position and received oxygen at 6 l/min. After stone focusing, an alfentanil infusion at an initial rate of 2.5 micrograms/kg min was started. Single shock waves were released as test shocks after approximately 2 min. If they were well tolerated, stone fragmentation was begun. If not, more alfentanil was allowed to accumulate until continuous treatment was tolerated. Further in- or decreases of the infusion rate were titrated according to patient response. Registered variables included the required alfentanil loading dose, maintenance and total doses, and the applied shock wave energy approximated by multiplication of shock wave number and voltage squared.(ABSTRACT TRUNCATED AT 250 WORDS)