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Chapter 073. Enteral and Parenteral Nutrition (Part 7)

Protein or Amino Acid Requirements Although the recommended dietary allowance for protein is 0.8 g/kg per d, maximal rates of repletion occur with 1.5 g/kg in the malnourished. In the severely catabolic patient, this higher level minimizes protein loss. In patients requiring SNS in the acute care setting, at least 1 g/kg is recommended, with greater amounts up to 1.5 g/kg as volume, renal, and hepatic tolerances allow. The standard parenteral and enteral formulas contain protein of high biologic value and meet the requirements for the eight essential amino acids. In protein-intolerant conditions such as renal and hepatic failure, modified. | Chapter 073. Enteral and Parenteral Nutrition Part 7 Protein or Amino Acid Requirements Although the recommended dietary allowance for protein is 0.8 g kg per d maximal rates of repletion occur with 1.5 g kg in the malnourished. In the severely catabolic patient this higher level minimizes protein loss. In patients requiring SNS in the acute care setting at least 1 g kg is recommended with greater amounts up to 1.5 g kg as volume renal and hepatic tolerances allow. The standard parenteral and enteral formulas contain protein of high biologic value and meet the requirements for the eight essential amino acids. In protein-intolerant conditions such as renal and hepatic failure modified amino acid formulas should be considered. In hepatic failure higher branched-chain amino acid-enriched formulas appear to improve outcomes. Conditionally essential amino acids like arginine and glutamine may also have some benefit in supplemental amounts. Protein nitrogen balance provides a measure of feeding efficacy of PN or EN. It is calculated as protein intake 6.25 because proteins are on average 16 nitrogen N minus the 24-h urine urea N UUN plus 4 g N which reflects other N losses. In the critically ill a mild negative balance of 2-4 g N d is usually achievable with a similarly mild positive balance in the recuperating patient. Each g N represents approximately 30 g lean tissue. Mineral and Vitamin Requirements Parenteral electrolyte vitamin and trace mineral requirements are summarized in Tables 73-4 73-5 and 73-6. Electrolyte modifications are necessary with substantial gastrointestinal losses from nasogastric drainage or intestinal losses from fistulas diarrhea or ostomy outputs. Such losses also imply extra calcium magnesium and zinc losses. Excessive urine or potassium losses with amphotericin or magnesium losses with cisplatin or in renal failure necessitate adjustments in sodium potassium magnesium phosphorus and acidbase balance. Vitamin and trace element requirements are