الفهرس 
Nutritional and metabolic requirement in crtically ill patientOnly 14 pages are availabe for public view
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Abstract
Nutritional adequacy is essential to life for maintaining health and recovery from health problems; therefore it’s no doubt critically significant for patients with special needs to meet their increased metabolic needs and correct negative nitrogen balance as in hypermetabolic ICU patients
Acute stress caused by accidental or surgical injury, sepsis, burns or other serious illnesses, results in the outpouring of counter-regulatory endocrine hormones, cytokines and lymphokines. This results in changes in substrate utilization and substance synthesis rates, as well as catabolism and hypermetabolism. Consequently, there is loss of fat and lean body (muscle) mass, Thus, it is not surprising that this abnormal metabolic milieu causes disordered utilization of exogenously administered nutrients
A full nutritional assessment allows the calculation of appropriate feeding goals. The route of feeding (enteral or parenteral) is determined by the presence or absence of a functioning intestine and hemodynamic status of the patient. The specific roles of carbohydrates, fats, and protein need to be considered in order to prevent overfeeding and other complications.
The most important stimulus for gut growth and function is the presence of nutrients within the gastrointestinal tract. In the absence of luminal stimuli or intestinal nutrients, the small and large bowels atrophy not only in the absorptive cells and brush border enzymes but also in the mucus-secreting cells and the gut-associated lymphoid tissue. Enteral nutrients mediate many of their indirect enterotropic effects by stimulating gut hormones such as gastrin, neurotensin, bombesin, and enteroglucagon
Parenteral nutrition should be initiated only when the gastrointestinal tract is nonfunctional or when it is impossible to obtain enteral access. However, enteral nutrition frequently results in hypocalorie feeding. Even though there is no evidence for or against it, it seems reasonable to supplement enteral with parenteral nutrition as a safe and effective means to achieve earlier optimal calorie intake when the enteral approach does not deliver the estimated calories. There is also no evidence that patients without risk factors will benefit from enteral or parenteral feeding if the expected duration of inability to tolerate enteral feeding is less than 7 to 10 days.
Over the last two decades, clinical nutrition has evolved from nutritional support intended only to cover patient’s needs to nutrition therapy selected according to patient’s disease. This new approach results from growing awareness that patient’s health status is closely related not only to quantitative but also to qualitative nutrient intakes.
full In theory, a ‘pharmaconutrition’ approach involves a rigorous step-by-step procedure of development that may appear limited but is the prerequisite for new nutritional therapeutic strategies based on sound scientific principles. To do so, the concept of an immuneenhancing diet applicable to a wide range of pathologies should be progressively replaced by disease-dedicated nutrition therapy.
Nutrients that go into the cocktail should be selected not only empirically but also after an in-depth evaluation of their individual and net effects, because it is likely that the interactions between nutrients may cancel or enhance their individual pharmacological properties. The resulting formula should be then administered apart from standard nutrition via an enteral or parenteral route to ensure full delivery of the expected doses. Finally, the optimum administration schedule (i.e. dose, route, timing and duration) should be determined in well conducted clinical trials with homogeneous population and sufficient number of patients.
Such a development procedure would make the acceptance of the ‘pharmaconutrition’ concept easier for the medical world and health authorities (i.e. level A of recommendation, reimbursement).