RECENT GUIDELINES IN PERIOPERATIVE IMMUNONUTRITION IN LIVER TRANSPLANT PATIENTS AND THEIR EFFECT ON OUTCOME

Abstract

SUMMARY T he liver orchestrates various physiological processes essential for a well-nourished state. It integrates several biochemical pathways of the metabolism of carbohydrates, fat, proteins and vitamins, as well as the secretion and excretion of bile and the transport of lipids, all of which are involved in muscle and protein metabolism Protein-energy malnutrition (PEM) is a common problem in patients with end-stage liver disease (ESLD) awaiting OLT. This applies to nearly every etiology of ESLD. PEM is a risk factor for morbidity and mortality after liver transplantation (LT). A patient’s nutritional status can worsen rapidly during the post operative period due to preoperative malnutrition, surgical stress, immunosuppressive therapy, post-interventional complications, postoperative protein catabolism and fasting periods. Protein-energy malnutrition predisposes a patient to complications, such as a compromised respiratory function and delayed physical rehabilitation, and it also increases a patient’s stay in the hospital and intensive care unit, blood usage and hospital charges. PEM adversely affects both the patient and graft survival, the patient quality of life after OLT and the response to stress, including the stresses of infection and surgery. All patients being prepared for LT should undergo a complete nutritional assessment. Traditional assessment tools are not accurate in patients with liver disease due to fluid retention, and the effects of liver dysfunction on protein synthesis. No gold standard for assessment exists at this time. The initial assessment should begin with a careful history to document weight loss, nausea, anorexia and the use of specialized diets and supplements. A complete physical examination should be performed to search for changes in the oral mucosa, skin and hair, thickness of subcutaneous fat and for muscle wasting, all of which are associated with chronic liver disease. A subjective global assessment (SGA) combines a thorough history-taking and physical examination and rates patients as either ‘‘well-nourished’’, ‘‘moderately malnourished’’, or ‘‘severely malnourished’’. The ability of nutrients to influence the activities of cells of the immune system has been termed “immunonutrition”, although this term has most frequently been associated with the use of specific nutrients or combinations of nutrients in critically ill patients. These patients typically receive artificial nutrition, through the parenteral or enteral routes. The overriding notion of immunonutrition is that nutrients can improve cell-mediated immune responses in away that is clinically meaningful, but in the context of patients requiring artificial nutrition this concept is extended to include modification of hyper-inflammatory processes (including oxidative stress) and improvement in gut barrier function, so preventing bacterial translocation.