الفهرس 
? Nutritional requirement and assessmentOnly 14 pages are availabe for public view
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Abstract
Nutrition is an important aspect of patient care in acute or chronic critical illness. Appropriate nutritional support during the acute phase of critical illness has the potential to reserve or mitigate adverse consequences of poor nutritional status.
An increasing nutritional deficit during a long ICU stay is associated with increased morbidity (infection rate, wound healing, mechanical ventilation, length of stay, duration of recovery and costs).
Early nutritional support, provided within 24 hours of injury or intensive care unit (ICU) admission, is a key component in the treatment of critically ill patients and may reduce mortality by 8% to 13%.
The nutritional state of hospitalized patients reflects directly on their clinical course, even that there are greater rate of hospital-acquired diseases and greater risk of clinical complications among malnourished patients, increasing the hospital length of stay (LOS) and reducing quality of life. This leads to high hospital costs because these patients have a greater need for intensive care or specialized services.
Medical and surgical ill patients are subjected to stress, infection and impaired organ function, resulting in a hypercatabolic state, leading to metabolic derangement and malnutrition.
The incidence of malnutrition worsens overtime in patients who require prolonged hospitalization.
Critically ill patients are characterized by a number of alterations in carbohydrate, lipid, amino acid, protein and electrolytes metabolism.
It was recognized that ICU patients are unique with varying nutritional requirements during their stay and understanding the issues involved such as tight glycemic control, the effects of over- and underfeeding will ultimately lead to a reduction in morbidity and mortality.
The nutritional status of a critically ill patient depends on a part on the nutritional therapy given during acute critical illness and the primary function of the nutritional assessment is to identify pre-existing malnutrition in order to prevent or minimize further loss of body weight, particularly of cell mass, composition and function.
Both enteral nutrition (EN) and parenteral nutrition (PN) are associated with complications, so clear guidelines should be set, these guidelines may lead to more successful enteral feedings, earlier achievement of caloric goals, a lower rate of complications, and it is hoped a better outcome.
The enteral nutrition is the preferred route for delivering of nutritional support in critically ill patients and thought to offer several advantages over the PN; it is more physiological, may help restore or maintain normal gastrointestinal function, and was associated with a reduced risk of infectious complications and cost savings in ICU patients in relative to PN.
Enteral nutrition (EN) started within 48 hours of admission resulted in a significant reduction in multiorgan failure, pancreatic infectious complications, and mortality. These significant differences between enteral (EN) versus parenteral nutrition (PN) faded away when nutrition support started after 48 hours of admission.
The principal indication for enteral nutrition (EN) is a functional gastrointestinal tract with sufficient length and absorptive capacity and the inability to take nutrients through the oral route either totally or in part. While the process of administering enteral nutrition (EN) may appear less complex compared with parenteral nutrition (PN), serious harm and death can result due to potential adverse events occurring throughout the process of ordering, administering, and monitoring.
Guidelines suggest that when enteral feeding is not possible, parenteral nutrition (PN) should be initiated within 7 days or within 3 days. Among such patients who have protein-energy malnutrition at the time of admission to the ICU, the American clinical practice guidelines suggest that parenteral nutrition (PN) should be initiated without delay.
The indications for combined enteral and parenteral nutrition are expected to increase in the future. Several studies have shown that the protein-energy deficit frequently observed with the use of enteral nutrition (EN) alone is associated with increased morbidity and mortality. Thus, avoiding nutritional deficiencies is a key objective of nutritional therapy in intensive care. As enteral nutrition (EN) is often difficult to fully optimize in the first three days following ICU admission, supplementing enteral with parenteral nutrition could allow a better coverage to help achieve the energy target and limit the protein-energy deficit.
The nutrients most often studied for immunonutrition are L-arginine, L- glutamine, branched chain amino acids, omega-3 fatty acids, nucleotides, selenium, beta carotene, and vitamins E, C, and A. The use of these products has been called ”immunonutrition” and these products have been called ”immune enhancing diets”
The increasing use of the immune enhancing diets in hospitals throughout the world and the substantial number of publications in the clinical literature evaluating their effect on clinical outcomes in randomized clinical trials make it appropriate to develop recommendations for their optimal utilization.