Fluid absorption during flexible ureteroscopy with intelligent control of renal pelvic pressure: a randomized controlled trial

To investigate fluid absorption and its influencing factors during flexible ureteroscopy with intelligent control of renal pelvic pressure (RPP).

A total of 80 patients with upper urinary tract calculi underwent flexible ureteroscopy with intelligent control of RPP by pressure-measuring ureteral access sheath and were randomly divided into four groups. The RPP of Groups A, B, and C were set at – 5, 0 and 5 mmHg, respectively. Conventional flexible ureteroscopy with uncontrolled pressure served as control Group D. The perfusion flow rate was set at 100 ml/min in the four groups, with 20 patients in each group. The fluid absorption was measured by 1% ethanol every 10 min. Operation time, stone-free rate, and complications were recorded.

Seventy-three patients were finally included in the RCT. The general and preoperative data of the patients were comparable between the groups. The fluid absorption of Groups A, B, and C was significantly less than that of Group D (P < 0.01). Fluid absorption and operation time were positively correlated, and the correlation coefficients R were 0.864, 0.896, 0.918, and 0.947, respectively (P < 0.01). The fluid absorption of patients with vomiting, fever and ureteral injury was greater than that of patients without complications in the four groups (P < 0.01). In different groups, fluid absorption was greater in patients with ureteral injury Post-Ureteroscopic Lesion Scale (PULS) 1–3 than in noninjured patients (P < 0.01).

Flexible ureteroscopy with intelligent control of RPP effectively reduces the absorption of perfusion fluid. Operation time and ureteral injury are also key factors affecting perfusion fluid absorption.

NCT05201599; August 11, 2021.