In-vivo porcine intrarenal pressure-irrigation flow characterization at various outlet resistances

You have accessJournal of UrologyCME1 Apr 2023MP68-04 IN-VIVO PORCINE INTRARENAL PRESSURE-IRRIGATION FLOW CHARACTERIZATION AT VARIOUS OUTLET RESISTANCES Ron Marom, Julie J. Dau, Marne M. Louters, 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 , Marne M. LoutersMarne M. Louters 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.0000000000003331.04AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Modern ureteroscopy techniques sometimes necessitate rapid irrigation rates to manage visualization and mitigate temperature elevation during laser lithotripsy. However, faster irrigation rates can elevate intrarenal pressure (IRP) which might in turn cause pressure induced adverse effects (e.g., sepsis). In this study we sought to assess IRP as a function of irrigation rate at different outlet resistances in an in-vivo porcine model. METHODS: Ureteroscopy was performed in a porcine model with a prototype ureteroscope containing a pressure sensor at its tip. A modified Ureteral Access Sheath (mUAS) was configured to accommodate the ureteroscope and adjust outflow resistance. Four different resistant values from low to very high were utilized to simulate a range of outflow scenarios. These resistances were subsequently calculated to be 2.59, 3.78, 5.61, 10.34 (cmH2O/(ml/min)). The distal end of the ureteroscope was fixed inside the renal collecting system. For each outlet resistance steady state IRP was measured across a range of irrigation rates. Using MATLAB, the pressure/flow relationship was plotted, and a linear regression was calculated from the linear portion of the curve. RESULTS: Similar trends were seen with all four outflow resistances scenarios. At lower irrigation rates the pressure change in response to increased irrigation was gradual and nonlinear, likely reflecting a “compliant” phase of the renal collecting system. Once IRP reached ∼15 cmH2O, pressure increased in a linear fashion with irrigation rate, suggesting that the distensibility of the collecting system had become saturated. CONCLUSIONS: The relationship between outlet resistance and IRP is an important concept to understand when considering safe parameters to use in ureteroscopy. Knowledge of outflow resistance and the IRP response to increased irrigation rates may aid decision making regarding placement of a ureteral access sheath. Furthermore, the mUAS is an important tool for controlling outlet resistance in experimental biologic systems and ureteroscopic studies. Source of Funding: Boston Scientific © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e953 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 Marne M. Louters 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 ...