[Nutritional support therapy during treatment of chronic critical illness]

Chronic critical illness (CCI) refers to a group of critically ill patients who survive the acute phase of intensive care, but with persistent organ dysfunction, thus entering a chronic period of continuous dependence on life support system, and still need to stay in intensive care unit (ICU) for a long time. Persistent inflammatory response-immunosuppression-catabolic syndrome (PICS) is the main pathophysiological feature of CCI. Three factors interact to form a vicious circle, leading to poor prognosis. Nutritional support therapy is a key link in the comprehensive treatment of CCI. Enteral nutrition (EN) should be started as soon as possible if conditions permit. If EN can not be implemented, temporary or transitional parenteral nutrition (PN) should be used, and EN should be added gradually in time. At the same time, the amount of PN should be gradually reduced. When EN meets more than 60% of patients' energy and protein requirements, PN can be considered to be discontinued. The main strategies and functions of CCI nutritional support therapy are as follows: strengthening high protein supply to correct negative nitrogen balance and inhibit catabolism, selecting branched chain amino acids (BCAA) to promote anabolism, using immunomodulators (arginine, ω3 polyunsaturated fatty acids) to improve immune suppression and inflammatory response, supplementing micronutrients (vitamins and trace elements) to counteract the decrease in intake and the increase in consumption, and adding probiotics to maintain the intestinal microecological balance, and so on. Reasonable nutritional support therapy not only improve malnutrition of CCI patients, but also help to reduce complications, thus speeding up rehabilitation, improving prognosis, shortening ICU hospitalization time, and even reducing mortality.