GLUTAMINE AND OTHER AMINO-ACID LOSSES DURING CONTINUOUS VENOVENOUS HEMODIAFILTRATION

Serum amino grams and daily losses of glutamine (Gln) and other amino acids (AAs) into diafiltrate were measured during the first 5 days of continuous venovenous hemodiafiltration (CVVHDF) in 6 ICU patients wit h acute renal failure (ARF). Four patients had ARF as a part of multip le organ failure (MOF) of septic origin, and 2 patients had isolated A RF because of primary renal disease. During the study, all the patient s received defined total parenteral nutrition (TPN). The mean daily AA losses into dialysate were relatively low (0.61 +/- 0.1 gN) and reach ed 4.5% of the daily AA substitution. Gin represented 32.7 +/- 5.9% of the total AA losses (0.19 +/- 0.04 gN). Serum levels of Gln (p = 0.00 2) and of most other AAs were significantly lower in the patients than in the control subjects (AA analysis in 16 healthy volunteers). Pheny lalanine (Phe) was the only AA that was increased significantly (p < 0 .01) in the patients. The mean patient serum concentrations of Phe and tyrosine were significantly higher (p < 0.03) than the correspondent concentrations in dialysate, but the lysine concentration was higher i n dialysate (p < 0.03). The serum and dialysate concentrations of othe r AAs did not differ. Gin in serum decreased significantly (p < 0.03) on the second day of CVVHDF but returned to the baseline levels subseq uently. Serum concentrations of Phe increased on the second day of CVV HDF (p < 0.05). Serum concentrations of other AAs remained stable duri ng the whole study. We conclude that Gin losses into dialysate during CVVHDF are relatively low, but CVVHDF itself may induce changes in Gln metabolism and distribution that are reflected by a decrease of serum Gln levels at the institution of this treatment. Therefore, the need for Gin supplementation in ICU patients is even greater in the first d ays of CVVHDF.