If a PD patient has consistently poor ultrafiltration, which approach is appropriate?

• A. Discontinue PD.
• B. Ignore the issue.
• C. Evaluate membrane function and transport status; adjust dwell times; consider long-dwell icodextrin or CCPD; optimize prescription.
• D. Increase dialysate volume.

Answer: (C)

When ultrafiltration is persistently poor on PD, the best approach is to tailor the dialysis prescription to the patient’s peritoneal membrane function and transport characteristics. Start by assessing how quickly the membrane moves water and solutes, typically using a transport status evaluation or PET, along with the patient’s fluid status and residual kidney function. This helps determine whether the issue is due to membrane transport properties or other factors.

Then adjust the dwell times to optimize the osmotic gradient. For high transporters, shorter dwell times help maintain the osmotic gradient and improve ultrafiltration, while for slower transporters, longer dwells can enhance fluid removal because more time allows osmotic-driven water transfer. If ultrafiltration remains insufficient after optimizing dwell times, consider using a long-dwell osmotic agent like icodextrin for the daytime or long nocturnal dwell, which provides a sustained gradient and can significantly boost UF. Switching to or incorporating continuous cycling PD (automated PD) can also help by delivering longer, efficient dwell periods during sleep. Finally, optimize the overall prescription by adjusting dialysate glucose concentrations, exploring icodextrin use, and ensuring the exchange pattern fits the patient’s membrane transport and daily routine, while also addressing potential contributing factors such as catheter function, adherence, and nutritional status.

Discontinuing PD or ignoring the issue isn’t appropriate, and simply increasing dialysate volume without aligning with transport status is unlikely to improve ultrafiltration.