There is ongoing debate about the role of nutrition during critical illness in terms of long-term outcomes. Even taking into account the inability to adequately assess all biological mechanisms associated with nutrition, it should be recognized that the available randomized trials, nutritional support during the early phase of critical illness, when considered in isolation from other treatment, may have very limited long-term functional value. This review focuses on recent clinical studies and evaluating the impact of critical nutrition on long-term physical and functional recovery. Critical survival is becoming an increasingly important subject of attention. Future research on nutritional support should consider specific factors that can provide measurable benefits in terms of both physical and functional recovery. These factors include the development of strategies to ensure adequate nutritional interventions, the provision of nutrition for a period of time in which biologically it is possible to observe differences in the results assessed, and the selection of appropriate methods of assessing the results recorded at clinically significant time points. One of these results is an assessment of muscle mass and function, as well as quality of life. In addition, selection of patients who are most likely to benefit from nutritional interventions and nutritional research after transfer from ICU deserves special attention.

Acute gastrointestinal injury develops in more than half of all patients in the intensive care unit, regardless of the underlying pathology. Determining the stage of acute gastrointestinal injury is necessary to choose the appropriate strategy of intensive therapy, leading to the fast gastrointestinal function recovery. The described strategy of intensive therapy, certain approaches to enteral therapy allow to improve prognosis and to reduce the duration of the disease among patients with severe gastrointestinal injury.

Prophylaxis, diagnostics and correction of nutritional status disturbances is considered as one of the main treatment methods of patients with COVID-19 infection-directed to resolve systemic inflammatory response and correction of metabolic response to a viral infection. Systemic Inflammatory Reaction (SIR) manisfestation as a result of viral infection leads to pronounced metabolic processes disturbances. The main metabolic manifestations of SIR is reflected as hypermetabolic-hypercatabolic syndrome with complex disturbances of protein, lipids and carbohydrates metabolism, increased consumption of carbohydrate-lipid reserves and breakdown of tissue proteins. Thus, adequate correction of metabolic disorders and a wholesome nutritional support, taking into account the clinical picture, severity of the disease, ongoing respiratory and intensive care therapy is an integral component in treating patients with COVID-19 infection which determines the efficiency of its treatment and reduction in mortality. Given the relevance of the problem, the authors decided that it was important to increase the COVID-19 treatment efficacy by producing guidelines based on the most fundamental provisions of the modern approach to nutritional support in critical patients with community acquired pneumonia, acute respiratory failure, ARDS, sepsis, multiple organ failure.

Due to the modern level of development of medicine, more and more patients survive after severe acute diseases. However, some of the patients remain dependent on life support systems. Therefore, a chronic critical condition is an urgent problem for patients in the intensive care unit. The main syndrome of this complex is maladaptive response to long-term existing stress factors. This review examines the main pathophysiological mechanisms of chronic critical illness, as well as the resulting metabolic disorders. Emphasis is placed on the systemic inflammatory reaction, the reaction of hypermetabolism - hypercatabolism, disorders of carbohydrate, protein and fat metabolism, the development of secondary sarcopenia. In conclusion, the volume of metabolic control and intensive nutritional and metabolic support, which are an important component of a comprehensive approach to the treatment of chronic critical illness, are also considered.