Figure 1828

Nutrition in patients with acute renal failure (ARF): decision making. Not every patient with ARF requires nutritional support. It is important to identify those who will benefit and to define the optimal time to initiate therapy [1].

The decision to initiate nutritional support is influenced by the patient's ability to cover nutritional requirements by eating, in addition to the nutritional status of the patient as well as the type of underlying illness involved. In any patient with evidence of mal-nourishment, nutritional therapy should be instituted regardless of whether the patient will be likely to eat. If a well-nourished patient can resume a normal diet within 5 days, no specific nutritional support is necessary. The degree of accompanying catabolism is also a factor. For patients with underlying diseases associated with excess protein catabolism, nutritional support should be initiated early.

If there is evidence of malnourishment or hypercatabolism, nutritional therapy should be initiated early, even if the patient is likely to eat before 5 days. Modern nutritional strategies should be aimed at avoiding the development of deficiency states and of "hospital-acquired malnutrition." During the acute phase of ARF (the first 24 hours after trauma or surgery) nutritional support should be withheld because nutrients infused during this "ebb phase" are not utilized, could increase oxygen requirements, and aggravate tissue injury and renal dysfunction.

The nutritional regimen should be adapted for renal failure when renal function is impaired. The multiple metabolic alterations characteristic of ARF occur when kidney function is below 30% of normal. Thus, when creatinine clearance falls below 50 to 30 mL per minute/1.73 m2 (or serum creatinine rises above 2.5 to 3.0 mg/dL) the nutritional regimen should be adapted to ARF. With the exception of severe hepatic failure and massively deranged amino acid metabolism (hyperammonemia) or protein synthesis (depletion of coagulation factors) renal failure is the major determinant of the nutritional regimen in patients with multiple organ dysfunction.

Enteral feeding is preferred for all patients, including those with ARF. Nevertheless, for a large portion of patients, parenteral nutrition—total or partial—will be necessary to meet nutritional requirements.

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