Blood flow rate effects in continuous venovenous hemodiafiltration on blood urea nitrogen and creatinine reduction.

The effect of blood flow rates (BFRs) in continuous venovenous hemodiafiltration (CVVHDF) on the clearances of blood urea nitrogen (BUN) and creatinine was studied using a retrospective chart review. Fifteen patients, 9 males and 6 females aged 50-85 years, were included in the study. Each patient had a primary cardiovascular diagnosis with acute renal failure (ARF) and was treated with CVVHDF on the Gambro PRISMA continuous renal replacement therapy (CRRT) machine using the COBE AN69 filter. Independent sample t-test, simple linear regression, ANOVA, and multiple comparisons were used. Simple linear regression revealed that BUN, creatinine, and difference in creatinine (DIFFCRTN) were best predicted by the number of hours of treatment. For every hour of treatment the BUN decreased by .08 mg/dl, the creatinine decreased by .01 mg/dl, and the DIFFCRTN increased by .01 mg/dl. The study concluded that patients on CVVHDF for greater than 72 hours had the greatest changes in BUN and creatinine when a BFR between 135-145 cc/min was used.