Abstract:

ABSTRACT  Objective：To evaluate the effects of different modes and doses of continuous renal replacement therapy (CRRT) on the clearance of amino acids. Methodology: Four patients requiring CRRT due to acute kidney injury were enrolled in this study. An Edward CRRT machine and AV-600 filter was used for CRRT. During each treatment session, the CRRT mode and dose was switched as following order every 20 minutes: continuous veno-venous hemodialysis (CVVHD) 2000ml/hr, 4000ml/hr, continuous veno-venous hemofiltration (CVVH) through pre-dilution route (pre-CVVH) 2000ml/h, 4000ml/h, CVVH through post-dilution route (post-CVVH) 2000ml/h, 4000ml/h. Each time before the switching of mode or dose, the blood samples were drawn from the pre-filter site (before replacement fluid infusion in pre-CVVH mode) and post-filter site, as well as effluent samples. All specimens were measured for urea nitrogen(UN) ,creatinine (Cr), 5 essential amino acids（Valine, Methionine, Isoleucine, Leucine, Lysine）, 2 semi-essential amino acids（Arginine, Histidine）, and 5 non- essential amino acids（Aspartic acid, Glumatic acid, Glycine, Citrulline, Ornithine）. Sieving coefficient (SC) and clearance of all the above-mentioned solutes were calculated based on the measured data. Results: The SCs of Aspartate acid and Glumatic acid were 0.5±0.04 and 0.48±0.07, respectively; and the SCs of other 10 amino acids were nearly 0.9. During various dose and mode, clearances of UN and Cr were comparable. With the dose of 2000ml/h, the clearances of UN/Cr under the CVVHD, Pre-CVVH, post-CVVH modes were 32.7/32.68ml/min, 23.95/24.69ml/min, 32.62/32.22ml/min, respectively; while with the dose of 4000ml/h, the clearances of UN/Cr under the CVVHD, Pre-CVVH, post-CVVH modes were 62.73/63.31ml/min,45.59/48.09ml/min, and 65.16/66.41ml/min, respectively. In all modes and doses, the clearance of Aspartic acid and Glumatic acid was much lower than other 10 amino acids, but without obvious differences of clearance between the 10 amino acids. With the dose of 2000ml/h, the clearances of Aspartate acid/Glumatic acid under the CVVHD, Pre-CVVH, post-CVVH modes were 18.08/16.79ml/min, 13.39/13.33ml/min and 19.1/19.6ml/min, respectively; while the clearance of other 10 amino acids were 28.31~32.18ml/min, 21.6~24.9ml/min and 27.38~32.4ml/min, respectively. With the dose of 4000ml/hr, the clearances of Aspartate acid / Glumatic acid under the CVVHD, Pre-CVVH, post-CVVH modes were 36.95/32.88 ml/min,29.37/26.86 ml/min and 37.82/34.79 ml/min, respectively；while the clearance of other 10 amino acids were 59.18~64.8ml/min, 46.71~50.64ml/min and 58.83~65.1ml/min, respectively. Conclusions: The mode of CRRT has an impact on the clearance of amino acids, but the effects of CRRT dose are more dominant.

Key words: Key words　continuous renal replacement therapy  , amino acids  , clearances;