We thank you for your question. We answered a similar question posted to the ISPD website in 2018, concerning how to manage a “blocked” PD catheter. At that time, we responded:       
Management of a “blocked” PD catheter (no inflow, no outflow, or both) depends on the cause of the PD catheter malfunction. Usually, it is good practice to first double-check that indeed all the clamps on the PD set are open, there are no kinks in the tubing, and try to reposition the patient. If not successful, then usual practice is to irrigate the PD catheter using at least a 10 mL size syringe with normal saline or 1.5% PD solution using a gentle push/pull technique to flush out fibrin or clots from the PD catheter (aseptic technique) (1). If fibrin is observed, then heparin 500 units per liter of PD fluid should be added IP to all the subsequent PD exchanges for the next 24 hours, then reassessed. Heparin will prevent further fibrin formation, but will not dissolve the fibrin.

If irrigation of the PD catheter is not successful, then the patient should be assessed for other causes of malfunction e.g. constipation, PD catheter malposition or kinking, or omental wrapping (2). An Xray (flat plate of the abdomen) is helpful to assess the patient for constipation or PD catheter malposition/kinking.

Of note: heparin is not usually thought to be effective at dissolving fibrin. However, some PD centres have reported administration of tissue plasminogen activator (tPA) (alteplase, Cathflo® Activase®) useful in dissolving fibrin in malfunctioning PD catheters. There is no standard protocol for use of tPA in a blocked PD catheter, but the Canadian British Columbia Provincial Renal Agency has one protocol published on their website (3).
We would not recommend “power” flushing a PD catheter. From an informal survey of members from different countries of the ISPD Nursing Committee, some countries use a 10 mL syringe for flushing the PD catheter, some a 20 mL syringe, while others a 50─60 mL syringe (in general, a larger size syringe will exert less pressure than a smaller size syringe). Adjacent tissue to the PD catheter may be damaged, especially on using a push/pull technique, when, on aspiration, the adjacent tissue may be pulled into the catheter. Our general recommendation would be to use a gentle “push/pull” technique, and stop if pressure or resistance is felt, or the patient complains of pain. Unlike research on flushing a central venous catheter, we could find limited published research on best practices in flushing a PD catheter.

1.British Columbia Provincial Renal Agency (2017). PD Procedures: Catheter Irrigation. Available at: http://www.bcrenal.ca/resource-gallery/Documents/PD%20Procedures-%20Catheter%20Irrigation.pdf
 
2.British Columbia Provincial Renal Agency (2017). PD Procedures: Inflow and Outflow Complications. Available at: http://www.bcrenal.ca/resource-gallery/Documents/PD%20Procedures-%20Inflow%20and%20Outflow%20Complications.pdf
 
3.British Columbia Provincial Renal Agency (2018). Alteplase (Cathflo®) Administration for Occluded Peritoneal Dialysis Catheter. Available at: http://www.bcrenalagency.ca/resource-gallery/Documents/Alteplase%20%28Cathflo%C2%AE%29%20Administration%20for%20Occluded%20Peritoneal%20Dialysis%20Catheter.pdf