Department of Urology, University of Michigan, 4432 Medical Science I, 1301 Catherine Street, Ann Arbor, MI, 48109-5330, USA.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
World J Urol. 2023 Mar;41(3):873-878. doi: 10.1007/s00345-023-04299-x. Epub 2023 Feb 7.
Since renal pelvis pressure is directly related to irrigation flowrate and outflow resistance, knowledge of outflow resistance associated with commonly used drainage devices could help guide the selection of the type and size of ureteral access sheath or catheter for individual ureteroscopic cases. This study aims to quantitatively measure outflow resistance for different drainage devices utilized during ureteroscopy.
With measured irrigation flowrate and renal pelvis pressure, outflow resistance was calculated using a hydrodynamic formula. After placement of a drainage device into a silicone kidney-ureter model, a disposable ureteroscope with a 9.5-Fr outer diameter was inserted with its tip positioned at the renal pelvis. Irrigation was delivered through the ureteroscope from varying heights above the renal pelvis. Renal pelvis pressure was measured directly from the port of the kidney model using a pressure sensor (Opsens, Canada). Outflow resistance was determined by plotting flowrate versus renal pelvis pressure. All trials were performed in triplicate for each drainage device inserted.
Flowrate was linearly dependent on renal pelvis pressure for all drainage devices tested. Outflow resistance values were 0.2, 1.1, 1.4, 3.9, and 6.5 cmHO/[ml/min] for UAS 13/15 Fr, UAS 11/13 Fr, UAC 6 Fr, UAC 4.8 Fr, and UAC 4.0 Fr, respectively, across the range of commonly used irrigation flowrates.
In this study, outflow resistance of different ureteral drainage devices was quantitatively measured. This knowledge can be useful when selecting which type and size of drainage device to insert to maintain safe renal pelvis pressure during ureteroscopy.
由于肾盂压力与灌流流速和流出阻力直接相关，因此了解与常用引流装置相关的流出阻力有助于指导在进行输尿管镜检查时选择输尿管鞘或导管的类型和尺寸。本研究旨在定量测量不同引流装置在输尿管镜检查中使用时的流出阻力。
通过测量灌流流速和肾盂压力，使用流体动力学公式计算流出阻力。在将引流装置放置在硅酮肾-输尿管模型中后，将外径为 9.5Fr 的一次性输尿管镜插入肾盂内，尖端位于肾盂内。通过输尿管镜从肾盂上方的不同高度输送灌流。使用压力传感器（加拿大 Opsens）直接从肾脏模型的端口测量肾盂压力。通过绘制流速与肾盂压力的关系来确定流出阻力。对于插入的每个引流装置，所有试验均重复进行三次。
对于所有测试的引流装置，流速与肾盂压力呈线性相关。在常用灌流流速范围内，UAS 13/15Fr、UAS 11/13Fr、UAC 6Fr、UAC 4.8Fr 和 UAC 4.0Fr 的流出阻力值分别为 0.2、1.1、1.4、3.9 和 6.5cmHO/[ml/min]。
在这项研究中，定量测量了不同输尿管引流装置的流出阻力。在选择插入哪种类型和尺寸的引流装置以在输尿管镜检查期间维持安全的肾盂压力时，这些知识可能会很有用。
