Energy Requirements Total energy expenditure comprises resting energy expenditure (two-thirds) plus activity energy expenditure (one-third) (Chap. 72). Resting energy expenditure includes the calories necessary for basal metabolism at bed rest. Activity energy expenditure represents one-fourth to one-third of the total, and the thermal effect of feeding is about 10% of the total energy expenditure. For normally nourished healthy individuals, the total energy expenditure is about 30– 35 kcal/kg. Although critical illness increases resting energy expenditure, only in initially well-nourished individuals with the highest systemic inflammatory response, such as that from severe multiple trauma, burns, closed head injury, or sepsis, do. | Chapter 073. Enteral and Parenteral Nutrition Part 6 Energy Requirements Total energy expenditure comprises resting energy expenditure two-thirds plus activity energy expenditure one-third Chap. 72 . Resting energy expenditure includes the calories necessary for basal metabolism at bed rest. Activity energy expenditure represents one-fourth to one-third of the total and the thermal effect of feeding is about 10 of the total energy expenditure. For normally nourished healthy individuals the total energy expenditure is about SO-35 kcal kg. Although critical illness increases resting energy expenditure only in initially well-nourished individuals with the highest systemic inflammatory response such as that from severe multiple trauma burns closed head injury or sepsis do total energy expenditures reach 40-45 kcal kg. The chronically ill patient with lean tissue loss has reduced basal energy expenditure and inactivity which results in a total energy expenditure of about 20-25 kcal kg. About 95 of such patients need 30 kcal kg to achieve energy balance. Because providing about 50 of measured energy expenditure as SNS is at least equally efficacious for the first 10 days of critical illness actual measurement of energy expenditure is not generally necessary in the early period of SNS. However in patients who remain critically ill beyond several weeks in the severely malnourished for whom estimates of energy expenditure are unreliable or in those who are difficult to wean from ventilators it is reasonable to actually measure energy expenditure and to aim for energy balance with SNS. Insulin resistance is associated with increased gluconeogenesis and reduced glucose utilization predisposing a patient to hyperglycemia. This is aggravated in patients receiving exogenous carbohydrate from SNS. Normalization of blood glucose levels by insulin infusion in critically ill patients receiving SNS reduces morbidity and mortality. In mild or moderately malnourished patients a .
