MP68-17 IN-VIVO THERMAL SAFETY VALIDATION OF URETEROSCOPY LASER POWER – IRRIGATION RATE PARAMETER PAIRS

Abstract

You have accessJournal of UrologyCME1 Apr 2023MP68-17 IN-VIVO THERMAL SAFETY VALIDATION OF URETEROSCOPY LASER POWER – IRRIGATION RATE PARAMETER PAIRS Ron Marom, Julie J. Dau, Khurshid R. Ghani, Timothy L. Hall, and William W. Roberts Ron MaromRon Marom More articles by this author , Julie J. DauJulie J. Dau More articles by this author , Khurshid R. GhaniKhurshid R. Ghani More articles by this author , Timothy L. HallTimothy L. Hall More articles by this author , and William W. RobertsWilliam W. Roberts More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003331.17AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: High-power laser lithotripsy settings improve stone ablation rate and treatment efficiency but also can induce elevated fluid temperatures to a point of toxic thermal dose. Previous in-vitro work mapped out safety boundaries based on laser power/irrigation rate pairs. Our objective in this study was to assess the thermal safety of a range of laser power settings at different irrigation rates in an in-vivo model. METHODS: Ureteroscopy was performed in an anesthetized in-vivo porcine model with a novel prototype ureteroscope containing a thermocouple sensor at its tip. The distal end of the ureteroscope was positioned in the middle of a small calyx and maintained there for the entire experiment. Three trials of 60 seconds laser activation were carried out at each selected power setting and irrigation rate. Using MATLAB, thermal dose was calculated from the time-temperature curves for each trial using the Sapareto and Dewey formula. The threshold of thermal tissue injury was considered to be 120 equivalent minutes. Laser power-irrigation rate parameter pairs were categorized based on number of trials that exceeded thermal dose and designated in the figure as red (Unsafe) – all trials exceeded threshold, yellow – some trials exceeded threshold, green (Safe) – no trials exceeded threshold. RESULTS: The collecting fluid temperature was increased with greater laser power and slower irrigation rate. The calculated thermal dose was above threshold for the power setting of 17.5 Watts and irrigation flow rate of 9 ml/min. With irrigation flow rates greater than 24 ml/min, none of the tested laser power settings (up to 48 Watts) exceeded the thermal dose threshold from 60 seconds of continuous laser activation. CONCLUSIONS: This study demonstrates a method to assess thermal safety of laser power-irrigation rate parameter pairs in an in-vivo porcine model. Building upon this foundation, other variables such as operator duty cycle and pedal activation time can be incorporated to more accurately replicate real-world patterns of clinical laser user. Additionally, the impact of mitigation strategies (higher irrigation flow rates, control of laser operator duty-cycle, limiting pedal activation time and use of chilled irrigation fluid) can be assessed with these standardized methods. Source of Funding: Boston Scientific © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e960 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ron Marom More articles by this author Julie J. Dau More articles by this author Khurshid R. Ghani More articles by this author Timothy L. Hall More articles by this author William W. Roberts More articles by this author Expand All Advertisement PDF downloadLoading ...