[Limitations and possibilities of enteral nutrition at an intensive care unit].

An updated revision has been made of the relevant nutritional and metabolic aspects of the so-called critical patient or of the patient exposed to aggressive measures. The different factors and circumstances that coincide in a situation of multiorgan failure in this type of patient have been assessed. The importance of the GI tract (Gut Hypothesis) and malnutrition has been underscored, both as the origin of Multisystemic Failure and in the application of possible therapeutic measures. A special point has been made on the importance of sustaining small bowel function, and on the adaptation mechanisms regarding the controversy on the use of enteral nutrition in these situations.