Fluid-electrolyte and renal pelvic pressure changes during ureteroscopic lithotripsy

Area of Science:

• Urology
• Nephrology
• Medical Engineering

Background:

• Ureteroscopic lithotripsy is a common procedure for treating ureteral calculi.
• Understanding intrarenal pressure dynamics is crucial for patient safety and procedural outcomes.
• Previous studies have not fully elucidated the impact of irrigation pressure on renal pelvic pressure (RPP) during ureteroscopic lithotripsy.

Purpose of the Study:

• To evaluate changes in fluid-electrolyte balance and renal pelvic pressure (RPP) during ureteroscopic lithotripsy.
• To determine the correlation between irrigation pressure, stone location, and RPP.
• To assess the safety of ureteroscopic lithotripsy concerning fluid-electrolyte shifts.

Main Methods:

• Fifteen patients with residual ureteral calculi post-minimally invasive percutaneous nephrolithotomy (MPCNL) were included.
• Renal pelvic pressure (RPP) was measured using urodynamic studies via percutaneous nephrostomy tubes at 50, 100, and 200 mmHg irrigation pressures.
• Fluid-electrolyte parameters (Hb, Hct, BUN, Creatinine, Na+, K+, Cl-) were recorded pre- and post-procedure.

Main Results:

• RPP significantly increased with rising irrigation pressures, from a baseline of 16.37 ± 3.14 cmH2O to 166.27 ± 33.08 cmH2O at 200 mmHg (p < 0.0001).
• Proximal ureteral calculi resulted in significantly higher RPP compared to distal and mid-ureteral calculi across all irrigation pressures (p < 0.0014).
• No significant changes were observed in fluid-electrolyte parameters (Hb, Hct, BUN, Creatinine, Na+, K+, Cl-).

Conclusions:

• Ureteroscopic lithotripsy causes a significant elevation in RPP, directly related to irrigation pressure and stone location.
• The procedure appears safe concerning fluid-electrolyte balance.
• Monitoring and managing intrarenal pressure are important during ureteroscopic lithotripsy, particularly for proximal ureteral stones.