Comparative clearance performance of two dialyser units used in the CVVHD mode

Continuous renal replacement therapies are now commonly used modes of support in acute renal failure (ARF). This study compared the clearance performance and it's degradation over time of two dialysers, one of flat plate configuration, and one of hollow fibre configuration (Asahi PAN 06 hollow fibre dialyser, Domedica, Sydney, and Hospal AN69HF flat plate dialyser, Gambro, Sydney) used in the CVVHD mode. Data were obtained from seven patients. Urea clearance was determined at commencement of dialysis and then at 12 hour intervals up to 48 hours post commencement. At each study time, urea clearance was determined at dialysis fluid (DF) flows of 500, 1000, 1500 and 2000 ml/hr. The procedure was repeated for each patient using the alternate dialyser. Comparisons of the two dialyser's urea clearance did not demonstrate any significant difference at any of the time periods studied. Overall, clearance was dependent upon (DF) flow with the diffusive clearance initially equal to DF flow but falling to 0.7 and 0.85 times increase in DF flow at 48 hours.