Comparative Study of Three Sedative Techniques During Shock Wave Lithotripsy.

Abstract

Background: Many authors found that dexmedetomidine is an effective, safe drug for sedation during extracorporeal shock wave lithotripsy (ESWL). Dexmedetomidine is a lipophilic α2- agonist ,which sedates patients by reducing sympathetic activity and the level of arousal ,thus patients lie calmly in beds but are easily roused to full consciousness. In the present study, the sedative, haemodynamics, and respiratory effects, and recovery time of dexmedetomidine and dexmedetomidine/fentanyl combination were compared to one of the commonly used sedative analgesic regimen (midazolam/fentanyl) in patients undergoing lithotripsy. Methods: Sixty ASA I - II patients undergoing (ESWL) were divided into three equal groups and were randomized to receive either dexmedetomidine (dex group), dexmedetomidine fentanyl combination (dex/fentanyl group) or midazolam fentanyl (midazolam/fentanyl group) . In dex group: Initial loading dose of dex 1 μg/kg was infused for 10 min followed by continuous infusion 0.1-0.7 μg/kg/h. In dex/fentanyl group, initial dose of 1 μg/kg dex was infused over 10 min followed by continuous infusion 0.1-0.7 μg/kg/h. At the same time, fentanyl infusion started 1 μg/kg over 10 min. In midazolam/fenatnyl group, midazolam 0.05 mg/kg and fentanyl 1 μg/kg were infused over 10 min followed by continuous infusion of normal saline. Heart rate (HR), mean arterial pressure (MAP), oxygen saturation (SpO2), and respiratory rate were recorded. Pain intensity was evaluated with a visual analog scale. Depth of sedation was monitored using Ramsay sedation score (RSS). Recovery time, rescue analgesic and sedative were recorded. Results: In all groups, no significant changes in oxygen saturation and respiratory rate were observed. In dex and dex/fentanyl groups there was a significant decrease in heart rate and mean arterial pressure during and post procedure. Supplemental fentanyl was required in 80% of patients in dex group to achieve a satisfactory level of analgesia (vs. 25% of patients in dex/fentanyl group and 40% of patients in midazolam/fentanyl group). Also 70% of patients in dex group received rescue midazolam vs. 15% in dex/fentanyl group and 20% in midazolam/fentanyl group. Time to home readiness was longer in dex,and dex/fentanyl groups than in midazolam/fentanyl group(80, 75, and 44 min), respectively. Conclusion: Dexmedetomidine alone does not appear to be suitable for sedation in patients undergoing ESWL. Combination of dexmedetomidine with fentanyl can be used safely and effectively for sedation and analgesia during ESWL, so it could be an alternative to conventional midazolam/fentanyl regimen but it is associated with longer recovery time.