Factors determining analgesic and sedative drug requirements during extracorporeal shock wave lithotripsy.
PURPOSE: The aim of this study was to determine what factors influence the analgesic and sedative requirements during extracorporeal shock wave lithotripsy (ESWL). MATERIALS AND METHODS: A retrospective study was carried out on 2,103 lithotripsy treatments performed over a 7-year period using an electromagnetic lithotriptor. Treatment with analgesics and anxiolytic drugs administered during ESWL was evaluated, and two new variables to determine the analgesic and sedative requirements were defined. A multivariant analysis model was established to determine which variables are related to or could predict the analgesic and/or sedative drug requirements. RESULTS: The most frequently used sedative drug was potassium chlorazepate which was used in 2,059 patients at a mean total dose of 25.6 mg. Pethidine was used in 2, 006 patients at a mean total dose of 56.3 mg, and fentanyl in 995 patients at a dose of 93.3 microg. In 52.4% of patients analgesic requirements were low, and in 76.6% sedative requirements were low. In 21.1% of patients analgesic drug requirements were high, and in 1. 8% of patients sedative drug requirements were high. The multivariant analysis showed that those requiring most analgesics were, the younger patients (p = 0.003), those who received a higher number of shock waves (p < 0.001) and those who needed more sedation (p < 0.001). Those who received the greatest amount of sedatives were women (p = 0.0026); younger patients (p < 0.001); those treated with higher voltages (p = 0.032), and patients with the highest analgesic requirements (p < 0.001). CONCLUSIONS: Predicting the analgesic drug requirements prior to ESWL is very difficult. The present study shows that young age, a greater discharge of shock waves and a high sedative drug requirement are factors clearly related to greater analgesic drug requirements. Higher sedative drug requirements are needed by women, younger patients, those receiving high discharge voltages and those with higher analgesic requirements.