The protein-fortified diet consists on an energy goal based on REE measurement and a protein target based on the most recent literature recommendations (1.2-2 g/kg/die) (2). Daily caloric requirement, and subsequent protein content, of patients enrolled in the intervention group will be calculated using formulas in Table 1 (10, 12, 13). For each patient will be calculated the Resting Energy Expenditure (REE) and daily protein requirement (1.2-2g/kg/die of body weight registered at the admission) and the corresponding caloric intake (1g = 4 kcal). Finally, total daily caloric intake will be calculated by adding kcal from protein (1g = 4kcal) on kcal from non-protein (50% of REE).

The standard diet consists on an energy goal based on weight formula (20-25 kcal/kg/die). According to the ICU nutritional protocol, EN is started at an initial rate of 10ml/h, and increased by 20ml/h every 12 hours in the absence of significant gastric residuals (<250ml), with the aim of reaching the energy goal within 72 hours from admission. The EN formulae used are standard (1-1,5 kcal/ml, 40g/l protein). If enteral nutrition is not tolerated or is not indicated, supplemental PN is used to make up the energy shortfall. The PN formula used is standard (1000 kcal/l, 37 g/l protein).

(gr)