A Study on the Application of NE Irrigation Fluid for Hemostasis in Flexible Ureteroscopic Lithotripsy: A Prospective Single-arm Interventional Study of Upper Urinary Tract Calculi.(NE: Norepinephrine)

Urinary stone disease is globally prevalent with rising incidence and recurrence, imposing heavy socioeconomic burdens. Flexible ureteroscopy has advanced stone treatment. Single-use flexible ureteroscopes (su-fURS) combined with negative pressure ureteral access sheath (NPUAS), recommended by urology guidelines, improve surgical safety and stone-free rates and can treat stones ≤3 cm. However, su-fURS has poorer image quality, bleeding during lithotripsy may blur vision, frequently impairing efficiency and safety. Norepinephrine (NE), a tyrosine-derived sympathomimetic amine, mainly activates α1 and β1 receptors. Doses above 3 μg/min trigger predominant α1-mediated vasoconstriction of arteries and veins. It can act on mucosal surfaces via irrigation fluid, making it favorable for initial hemostasis of injured mucosa. Firstly, this study aims to evaluate the efficacy and safety of low-concentration norepinephrine (NE) irrigation solution for hemostasis during lithotripsy performed with single-use flexible ureteroscope (su-fURS) combined with NPUAS, fifteen subjects will be enrolled in the study. Secondly, we explore the dose-effect relationships of four concentrations: 2 mg/3 L, 4 mg/3 L, 6 mg/3 L and 8 mg/3 L, and determine the optimal concentration by comprehensively evaluating hemostatic efficacy and safety. A total of 40 subjects will be enrolled, with 10 subjects in each concentration.