Liver failure protein requirements

Protein metabolism depends on both kidney and liver function therefore, protein requirements will be altered with decreased kidney or liver function (see Chap. 139). Critical illness (e.g., sepsis, burns, or trauma) will result in a hypercatabohc state in which there is increased protein synthesis and degradation. Consequently, protein requirements wiU be increased to 1.5 to 2 g/kg per day. In burn patients, protein requirements may be as high as 2.5 to 3 g/kg per day. Liver failure typically results in the need for protein restriction (0.5 g/kg per day) except if a hypercatabohc state is also present, in which case the requirement may be increased to 1.5 g/kg per day. Protein needs in renal failure are variable and affected by the various renal replacement therapies available. The apphcation of these guidelines requires both chnical judgment and frequent monitoring of renal and liver function, serum chemistries, chiucal condition, and nutrition outcomes (see Chap. 139). 

Nitrogen requirements for the patient with liver failure are not unlike those of normal subjects, but intolerance to protein is common, and protein restriction has been used successfully as part of the therapy. A dilemma arises when the diet becomes so restrictive that malnutrition results, and the patient becomes susceptible to infection and other comphcations. Overzealous use of protein to correct nutritional deficits invariably results in hepatic encephalopathy. 

Water Excess. Sometimes excessive water accumulates in the tissues, specifically the interstitial compartment. Outwardly, this condition is noted as swelling and it may occur in any area of the body. It is called edema, though some may still call it dropsy. In general, there are four causes of edema (1) elevated fluid pressure in the capillaries as in heart failure (2) low osmotic pressure in the blood due to decreased blood protein in such conditions as liver cirrhosis, kidney disease, severe burns, and starvation (3) blockage of the lymph vessels as caused by the parasitic worm, filariae, in the disease elephantiasis or (4) increased capillary permeability due to the release of histamine in allergic reactions. Edema may require the restriction of dietary sodium and/or diuretics. 

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