High protein intake during continuous hemodiafiltration: Impact on amino acids and nitrogen balance

Rinaldo Bellomo, H. K. Tan, S. Bhonagiri, I. Gopal, J. Seacombe, M. Daskalakis, N. Boyce

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Abstract

Aims: To study the effect of combined continuous veno-venous hemodiafiltration (CVVHDF) and high (2.5 g/kg/day) parenteral amino acid supplementation on nitrogen balance, amino acid losses and azotemic control in a cohort of patients with severe acute renal failure (ARF). Methods: We administered 2.5 grams/kg/day of amino acids intravenously to seven critically ill patients with ARF. We obtained paired blood and ultrafiltrate (UF) samples (n=20) and calculated amino acid clearances and losses, nitrogen balance, protein catabolic rate and total nitrogen losses. Results: The median total serum amino acid concentration was high at 5.2 mmol/L with particularly high concentrations of ornithine, lysine, and phenylalanine, but a low level of histidine. The median overall amino acid clearance was 18.6 ml/min (range: 12 to 29 ml/min). UF losses as percentage of administered dose were high for tyrosine (53.6%) but low for methionine (3.0%) and arginine (2.3%). A positive nitrogen balance was achieved in 7 (35%) of the 20 study days with an overall median nitrogen balance of -1.8 g/day. Urea levels were maintained at a median of 26.6 mmol/L. Conclusions: High protein intake increases the serum concentrations of most amino acids. Such protein supplementation, when coupled with CVVHDF, achieves a slightly negative overall nitrogen balance in extremely catabolic patients while still allowing adequate azotemic control.

Original languageEnglish
Pages (from-to)261-268
Number of pages8
JournalInternational Journal of Artificial Organs
Volume25
Issue number4
Publication statusPublished - 1 Jan 2002
Externally publishedYes

Keywords

  • Acute renal failure
  • Amino acids
  • Critical illness
  • Hemofiltration
  • Parenteral nutrition
  • Uremia

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