Basal Energy Expenditure (BEE)

  • Harris-Benedict Equations: provide estimate of BEE
    • Male Cal Req = 655.1 + 9.56 (wt in kg) + 1.85 (ht in cm) – 4.68 (age) x Activity Factor x Injury Factor
    • Female Cal Req = 66.47 + 13.75 (wt in kg) + 5.0 (ht in cm) – 6.76 (age) x Activity Factor x Injury Factor
  • Activity Factor
    • Confined to Bed: 1.2
    • Out of Bed: 1.3
  • Injury Factor
    • Major Surgery: 1.2
    • Mild Infection: 1.2
    • Moderate Infection: 1.4
    • Severe Infection: 1.8
    • Skeletal Trauma: 1.35
    • Head Trauma with Steroids: 1.6
    • Blunt Head Trauma: 1.35
    • Burns <40%: 1.5
    • Burns <100%: 1.95

Protein Requirement

  • Normal : 1-1.5 g/kg/day
  • Hepatic Encephalopathy : 0.6-0.8 g/kg/day
  • Renal Failure with HD/PD :
  • Renal Failure without HD/PD:

Types of Nutritional Support

Urinary Urea Nitrogen (UUN)

  • 24 hr urine assay to quantify BUN excretion
  • Balance of total g nitrogen in = total measured g of nitrogen out + about 4 g (for insensible losses)
  • Positive nitrogen balance: indicates anabolism
  • Negative nitrogen balance: indicates catabolism

Nutrition in Renal Disease

  • Malnutrition in hospitalized patients is associated with increased mortality [Incidence and recognition of malnutrition in hospital [BMJ 1994; 308:945–948]
  • Assessment of the nutritional status of critically ill patients is limited by the unreliability of traditional markers of nutritional status in critical illness in general, and AKI in particular
  • Prealbumin is excreted mainly by the kidneys and hence may be falsely elevated in patients with AKI [Assessment of nutritional status in renal diseases. In: Handbook of Nutrition and Kidney. Mitch WE, Klahr S (Eds). Philadelphia: Lippincott Williams & Wilkins, 2002, pp. 42–92]
  • Patients with AKI are hypercatabolic with a negative nitrogen balance (165), resulting from both increased protein catabolism and impaired protein synthesis

Continuous Renal Replacement Therapy (CRRT)

  • There is Markedly Increased Protein Catabolism in Most Patients Requiring CRRT: the use of CRRT enhances the clinician’s ability to provide adequate nutrition because of an improved ability to manage volume
    • Unfortunately, the recommended amount of protein in this population remains controversial and recommendations are based solely on expert opinion, because there are no data available from RCT
    • Although there are no studies demonstrating a benefit in outcomes (e.g., survival or dialysis-free days), consensus recommendations include nonprotein caloric intake of 20 to 30 kcal/kg body weight per day and a protein intake of 1.5 g/kg per day (168).
    • However, several studies have demonstrated a less negative or even positive nitrogen balance in those patients receiving up to 2.5 g/kg per day while receiving CRRT without evidence of adverse effects (169 –171).
    • An increase in nonprotein calories in critically ill patients with AKI does not improve nitrogen balance (172).


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