Amino acid losses during continuous high-flux hemofiltration in the critically ill patient.

Total amino acid losses were measured daily in the ultrafiltrate collected from eight patients with acute renal failure treated by continuous high-flux venovenous hemofiltration. All patients had type-1 respiratory failure and required mechanical ventilation. Four patients also suffered cardiogenic shock and were dependent on two or more inotropic drugs; the other four had Escherichia coli septicemia. All patients received identical daily parenteral nutrition as a continuous infusion. The overall mean serum amino acid values were greater in the group with cardiogenic shock (180 +/- 36 [SEM] mumol/L) compared to those with septicemia (131 +/- 26 mumol/L; p less than .05). The daily ultrafiltrate losses of amino acids were also greater, 4.2 +/- 0.7 mmol/24 h (1.1 g N) compared to 2.1 +/- 0.3 mmol/24 h (0.6 g N, p less than .05). For all patients there was a positive correlation between the serum amino acid value and ultrafiltrate loss (r = .84, p less than .001). However, the slopes of the regression curves for the two groups differed (p less than .001), suggesting that for the same plasma value the ultrafiltrate loss was greater for those patients with cardiogenic shock.