Abstract
Although the importance of nutritional therapy has been emphasized in nutritional guidelines for critically ill patients, there are few studies demonstrating the strong evidence of the nutritional therapy on long-term outcomes. Critical illness is associated with hypermetabolism and marked protein catabolism, and therefore muscle wasting is a frequent finding. Muscle loss and weakness seen in clinically has been associated with impaired function and poor clinical outcomes. Several international guidelines suggested that high doses of protein in the range of 1.2-2.0 g/kg/day may be required in the setting of the intensive care unit. However, we are not sure what the effect of administration exogenous protein/amino acids on muscle protein synthesis and balance during anabolic response. In another view, how can we optimize the doses of protein/ amino acids and what is the difference between via enteral and parenteral? Do we need the change of doses of protein/ amino acids for adjust the baseline of muscle volume in each patient, such as between young and elderly patients? Thus, we have many questions for protein delivery. The incidence of sarcopenia and frailty in the elderly has been increasing towards the future in Japan, and therefore, the number of critically-ill elderly patients with various degrees of malnutrition is also increasing. Optimal nutritional therapy needs to be initiated on admission to the intensive care unit. Although there is no definitive consensus, optimal provision of energy and protein to maintain muscle mass to maintain function is a mainstay. We are still in the inextricable maze for critically ill patients.
