Which condition indicates that a dialyzer may be clotting?

Rising transmembrane pressure (TMP) is a crucial indicator of dialyzer function, and an increase in TMP can signal potential clotting within the dialyzer. As blood flows through the dialyzer, it encounters resistance from clots or fibrin deposits that may be forming on the filter fibers. This resistance is reflected as a higher TMP, which indicates that the dialyzer is becoming less effective at filtering blood due to the presence of clotting or blockage. Monitoring TMP helps clinicians determine the health of the dialyzer and whether it requires replacement to ensure effective dialysis treatment.

The other options do not reflect the same level of concern for clotting in the dialyzer. Decreased arterial pressure may indicate issues with the blood flow or pump but does not directly suggest clotting, while decreased venous pressure could point to an issue with return flow rather than clotting itself. Clear blood in the dialyzer typically indicates effective filtration, suggesting that there is no clotting happening. Thus, rising TMP is the best indication that clotting may be occurring in the dialyzer.