[Requeriments of macronutrients and micronutrients]

Critically ill patients have important modifications in their energetic requirements, in which the clinical situation, treatment applied and the time course take part. Thus, the most appropriate method to calculate the caloric intake is indirect calorimetry. When this test is not available, calculations such as Harris-Benedict's may be used, although not using the so high correction factors as previously recommended in order to avoid hypercaloric intakes. The intake of a fixed caloric amount (comprised between 25-30 KcalKg/min) is adequate for most critically ill patients. Carbohydrates intake must be of 5 g/kg/day) maximum. Glucose plasma levels must be controlled in order to avoid hyperglycemia. With regards to fat intake, the maximum limit should be 1.5 g/kg/day. The recommended protein intake is 1.0-1.5 g/kg/day, according to the clinical situation characteristics. Special care must be taken with micronutrients intake, an issue that is many times undervalued. In this sense, there are data to consider some micronutrients such as Zn, CU, Mn, Cr, Se, Mo and some vitamins (A, B, C, and E) of great importance for patients in a critical condition, although specific requirements for each one of them have not been established.