Long-term performance of hemofilters in continuous hemofiltration.

We measured the filter performance of six polyamide hemofilters with a running time exceeding 72 h applied for continuous hemofiltration in intensive care patients. The sieving coefficients for urea and creatinine were close to unity and remained constant. The sieving coefficient of polyfructosan (mean molecular weight 3 kD) was around 0.75 and did not change with running time. The hydraulic permeability remained also unchanged. The relationships between blood pressure and blood flow and between blood flow and filtration rate remained linear, and the gradient did not change with time. We conclude that a daily routine change of polyamide hemofilters applied in continuous arteriovenous hemofiltration and presumably in continuous venovenous hemofiltration is not necessary within the first 72 h of treatment, unless a major decrease in the filtration rate occurs.