Department of Urology, University of Michigan, MI, Ann Arbor, USA.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
Urolithiasis. 2023 Jul 29;51(1):98. doi: 10.1007/s00240-023-01470-2.
To maintain visualization and control temperature elevation during ureteroscopy, higher irrigation rates are necessary, but this can increase intrarenal pressure (IRP) and lead to adverse effects like sepsis. The IRP is also dependent on outflow resistance but this has not been quantitatively evaluated in a biological system. In this study, we sought to characterize the IRP as a function of irrigation rate in an in vivo porcine model at different outflow resistances. Ureteroscopy was performed in a porcine model with a 9.5 Fr prototype ureteroscope containing a pressure sensor. A modified ureteral access sheath (UAS) (11/13 Fr, 36 cm) was configured to adjust outflow resistance. IRP-irrigation rate curves were generated at four different outlet resistances representing different outflow scenarios. At lower irrigation rates, the pressure change in response to increased irrigation was gradual and non-linear, likely reflecting a "compliant" phase of the renal collecting system. Once IRP reached the range of 35-50 cm HO, the pressure increased in a linear fashion with irrigation rate, suggesting that the distensibility of the collecting system had become saturated. The relationship between IRP and irrigation rate becomes linear during in vivo porcine studies once the initial compliance of the system is saturated. IRP is more sensitive to changes in irrigation rate in systems with higher outflow resistance. The modified UAS is a novel research tool which allows variance of outflow resistance to mimic different clinical scenarios. Knowledge of outflow resistance may simplify the decision to use an UAS.
为了在输尿管镜检查期间保持可视化和控制体温升高，需要更高的冲洗速率，但这会增加肾内压（IRP）并导致败血症等不良反应。IRP 还取决于流出阻力，但在生物系统中尚未对此进行定量评估。在这项研究中，我们试图在不同流出阻力的活体猪模型中描述作为冲洗速率函数的 IRP。在含有压力传感器的 9.5 Fr 原型输尿管镜的猪模型中进行输尿管镜检查。修改后的输尿管进入鞘（UAS）（11/13 Fr，36 cm）被配置为调节流出阻力。在代表不同流出情况的四个不同出口阻力下生成 IRP-冲洗速率曲线。在较低的冲洗速率下，响应增加冲洗的压力变化是逐渐的和非线性的，可能反映了肾集合系统的“顺应性”阶段。一旦 IRP 达到 35-50 cm HO 的范围，压力就会随着冲洗速率线性增加，这表明收集系统的可扩展性已经饱和。一旦系统的初始顺应性饱和，活体猪研究中 IRP 与冲洗速率之间的关系就会呈线性。在具有较高流出阻力的系统中，IRP 对冲洗速率变化更敏感。修改后的 UAS 是一种新颖的研究工具，它允许流出阻力的变化来模拟不同的临床情况。了解流出阻力可能会简化使用 UAS 的决策。
