Christina Kottooran, Jeffrey Twum-Ampofo, Jason Lee, Jennifer Saunders, Marle Franco, Jay Budrewicz, Brian H Eisner. "Evaluation of fluid absorption during flexible ureteroscopy in an in vivo porcine model."

Objective: The purpose of this study was to evaluate the relationship between renal pelvis pressure and fluid absorption during ureteroscopy in a live porcine model.

Materials and methods: Flexible ureteroscopy was performed in anesthetized female Yorkshire pigs. Prior to performing flexible ureteroscopy, a 0.014" pressure sensing guidewire (Comet™, Boston Scientific) was placed to monitor renal pelvis pressure. A simulated flexible ureteroscopy procedure was then performed for 1 hour. Infusion of irrigation fluid (5% ethanol in saline) at target renal pelvis pressures (37-150 mm Hg) was maintained for 1 hour using a pressure bag and real-time feedback from the pressure sensing guidewire. Venous blood was sampled every 10 minutes. The volume of irrigation fluid absorbed was estimated with established equations.

Results: A ureteroscopy procedure was performed in vivo in 18 porcine kidneys and the volume of irrigation fluid absorbed during the 1 hour ureteroscopy was calculated. The mean volume of irrigation fluid absorbed after 1 hour of simulated ureteroscopy was 7.6 ± 5.7, 10.8 ± 7.1, 26.0 ± 15.8, and 56.8 ± 22.3 mL at renal pelvis pressures of 37, 55, 75, and 150 mm Hg, respectively. Compared with ureteroscopy with renal pelvis pressure of 37 mm Hg, volume of fluid absorption was significantly greater at renal pelvis pressures of 75 mm Hg and 150 mm Hg (p = 0.026 and p=0.047, respectively). In addition, compared with ureteroscopy with renal pelvis pressure of 37 mm Hg, rate of absorption was significantly greater at renal pelvis pressures of 75 mm Hg and 150 mm Hg (p < 0.001 and p < 0.001).

Conclusion: In this study of an in vivo porcine model of ureteroscopy, increasing renal pelvis pressures during ureteroscopy were associated with increases in irrigation fluid absorption and increases in rate of fluid absorption.

BJU Int. 2022 Jul 21. doi: 10.1111/bju.15858. Online ahead of print.