Fresenius Nurse Practice Test 2026 – Complete Exam Prep

A decreasing KECN points to the dialyzer losing surface area because clotting inside the dialyzer blocks fibers and occludes the membrane pathways. When fibrin and cellular debris form clots, they reduce the actual surface area available for diffusion between blood and dialysate, so the dialyzer’s effective clearance drops. This direct impact on the membrane surface explains the drop in KECN most clearly. Membrane rupture would cause other issues like leaks, hypotension affects flow rather than surface area, and infection doesn’t mechanically reduce the dialyzer’s surface area.