What is the role of residual kidney function in fluid and toxin removal in PD?

• A. It provides no additional clearance.
• B. It increases toxin production.
• C. It reduces urine output.
• D. It provides additional clearance and urine output, aiding fluid balance; decline in RRF reduces overall dialysis adequacy.

Answer: (D)

Residual kidney function adds extra help beyond the peritoneal membrane by providing additional toxin clearance and urine production. This means total clearance during PD is the sum of what remains from the kidneys and what PD removes. The urine output from RRF also frees water, aiding fluid balance between PD exchanges. When RRF declines, both the toxin removal and the fluid-removal capacity drop, reducing overall dialysis adequacy. That’s why preserving RRF helps keep PD effective, and when it diminishes, adjustments to the PD prescription or modality may be needed to maintain solute control and fluid balance.