Amino acid losses and nitrogen balance during slow diurnal hemodialysis in critically ill patients with renal failure.

Objective: The effects of slow diurnal hemodialysis (slow HD) on amino acid losses and nitrogen balance were studied.

Design: Slow HD was conducted for 10 h during the day at the dialysate flow rate of 30 ml/min. The patients received total parenteral nutrition including 40 g of amino acids (6.08 g of nitrogen). The amino acid concentrations in plasma and dialysate were determined and the daily nitrogen balance was calculated from the urea nitrogen appearance.

Patients: Six critically ill patients with renal failure were entered into the study.

Results: Slow HD eliminated 48.5 +/- 4.4 mmol (6.2 +/- 0.6 g) of amino acids, representing 16% of the daily amino acid load. The estimated nitrogen balance was -2.3 +/- 1.3 g/day. Amino acid nitrogen lost in the dialysate was 1.0 +/- 0.1 g, contributing 43% of the daily negative nitrogen balance.

Conclusion: The amount of amino acid losses during slow HD should be taken into consideration when designing nutritional schedules for maintaining positive nitrogen balance in critically ill patients.