Objective
To determine daily amino acid and total protein losses in patients with acute renal failure receiving total parenteral nutrition (TPN) during treatment by continuous arteriovenous hemofiltration with hemodialysis (CAVHD).
Design
Prospective, nonrandomized study.
Setting
Patients in the ICU of a regional nephrology referral center.
Patients
Eight clearance studies of individual amino acids were performed in six patients with acute renal failure receiving TPN. Daily nitrogen intake was 9 g (one patient), 14 g (two patients), and 18 g (three patients). The clearances of individual amino acids were measured at two dialysis flow rates to calculate daily amino acid and total protein losses.
Results
Amino acid clearance rates ranged from 7.8 ±PT 2.2 (glutamic acid) to 25.2 ±PT 4.8 mL/min (3-methylhistidine) at a dialysate flow rate of 1L/hr and from 13.6 ±PT 1.7 (tryptophan) to 33.7 ±PT 4.3 mL/min (3-methylhistidine) at a dialysate flow rate of 2 L/hr. These results represent daily amino acid losses of 1.5 ±PT 0.4% (glutamic acid) to 111.6 ±PT 16.6% (tyrosine) of the nutritional input at a dialysate flow rate of 1 L/hr and 2.1 ±PT 0.6% (glutamic acid) to 145.8 ±PT 17.8% (tyrosine) at a dialysate flow rate of 2 L/hr. Total losses would represent 8.9 ±PT 1.2% and 12.1 ±PT 2.2%, respectively, of the daily protein input.
Conclusions
These studies confirm that amino acid clearances are relatively high during CAVHD and daily losses should therefore be considered.
