mixed inflammatory response syndrome (MARS), and immune failure. And the degree of this immune imbalance is directly influenced by the intensity and duration of the stress. More importantly, this immune response disorder is present throughout the course of critical illness, inducing changes in cellular and even organ function, and severely affecting the course of critical illness. Nutritional conditioning treatment of immune response imbalance, that is, some nutrients with immunomodulatory function are added to the nutritional solution, so that the nutritional Nanjing Military Region General Hospital General Surgery Department Li Ning plays the role of immunomodulation while playing the role of nutritional support. Due to the inadequacy of research methods. Immunonutrition has not yet yielded convincing clinical results. However, the pharmacological effects of various nutrients have attracted widespread interest and have formed an emerging discipline, namely pharmaconutrition, and have changed the understanding of traditional nutritional support”.J. Currently, the more commonly accepted nutrients with modulating immune responses are glutamine (Gin), ∞-3 poly unsaturated fatty acids (PUFA), arginine (Arg), vitamin E, carotenoids, and the antioxidant glutathione. Among them, the most concerned are ‘o.3PUFA (fish oil), Gin and nucleotides. ∞_6PuFA is metabolized in vivo to produce dienoic acid epoxides and tetraenoic acid lipoxides, which have effects such as exacerbating inflammatory responses and suppressing immune function. The metabolites of ∞PUFA are trienoic acid epoxides and pentaenoic acid lipid oxides, whose chemical structures are similar to those of (Io-6PUFA, but their biological activities are weak. If fish oil is used to replace soybean oil, the adverse effects of ‘I)I-6PuFA on the organism can be significantly reduced. This is of great importance for immune modulation in diseases such as severe trauma, infection, organ transplantation and immune dysfunction. Therefore, fish oil fat emulsions have been widely used in clinical practice and have achieved significant therapeutic effects Fear J. Gin is the most abundant amino acid in the body and has a variety of physiological functions, including participating in the transport of nitrogen in the body, synthesizing Arg, regulating acid-base balance, serving as a precursor for the synthesis of purines, pyrimidines, nucleotides, amino sugars and glutathione, providing energy and It provides energy and raw materials for cellular synthesis, plays an antioxidant role, etc. In pathological conditions such as infection and stress, Gln stores are depleted and its above functions are affected. In this case, Gin supplementation can provide energy and proliferation materials for immune cells and improve the immune function of the body. The tonic effect on intestinal mucosal epithelial cells helps to maintain the intestinal mucosal barrier, reduce bacterial translocation, systemic infection and inflammatory response, protect organ function, and help to maintain endostasis. Therefore, supplementation of Gin to critically ill patients has become a routine clinical treatment. Nutritional management of organ dysfunction in critically ill patients Critically ill patients are often complicated by one or more organ dysfunctions or disorders, of which lung, liver, kidney, gastrointestinal and cardiac dysfunctions are the more common complications. The intestinal mucosal erosion, ulceration, atrophy, necrosis and apoptosis caused by various factors in critically ill patients lead to increased intestinal mucosal permeability and intestinal barrier dysfunction, causing bacterial translocation and endotoxin translocation o that is, bacteria or (and) endotoxin in the intestinal tract cross the damaged intestinal barrier into the portal vein, activating the hepatic barrier into the portal vein, activating hepatic macrophages or acting systemically to promote SIRS and multiple organ dysfunction syndrome (MODS), forming a vicious cycle. Therefore, some scholars believe that the intestine is the “engine” for the development of MODS in critically ill patients, and is even the “central organ” of stress. In recent years, a new concept of clinical nutrition, called ecoimmunonutrition, has been proposed, which more perfectly reflects the therapeutic characteristics of gastrointestinal nutrition. Because the gastrointestinal tract is not only the place for digestion and absorption of nutrients, but also the largest immune organ and the largest bacterial reservoir in the body, which is the main defense line of the body against foreign antigens and disease-causing microorganisms. Once the immune function of gastrointestinal tract is damaged, the dysbiosis of intestinal flora will cause systemic diseases, such as bacteremia, sepsis, endotoxemia and allergy, and even develop into multi-organ dysfunction. Ecological immune nutrition preparation consists of probiotics and prebiotics. Probiotics are microbial food adjuvants that have beneficial effects on host physiological functions by modulating intestinal mucosa and systemic immunity, improving nutrition and the balance of microflora and enzymes in the intestine. Prebiotics are a class of non-digestible food components that not only cannot be broken down by digestive enzymes in the human digestive tract, but also cannot be absorbed in the small intestine and are directly used as a carbon source by certain bacteria in the colon, thus selectively stimulating the growth of one or several probiotic bacteria in the colon and promoting the health of the organism. Prebiotics include fiber and oligo-oligosaccharides. Fibers are usually divided into three categories, soluble fibers (such as gums and resins), insoluble fibers (such as cellulose), and complex fibers (such as wheat bran). Oligosaccharides include hydrosugar, lactulose, inulin and fructooligosaccharides. Soluble fiber prolongs gastric emptying time and intestinal transit time, which in turn affects metabolism including improved glucose tolerance. Only 50% of cellulose is degraded in the colon, 80%-90% of non-cellulose and polysaccharides are degraded, and almost 100% of pectin is fermented, with the final end product being short-chain fatty acids. Short-chain fatty acids are ideal oxidation substrates for the colonic epithelium and are important respiratory fuels for intestinal mucosal cells, which are necessary to maintain the integrity, regeneration and repair of the intestinal mucosa¨o. Recent studies have found that fish oil-rich EN and PN have a very protective effect on liver and lung function in patients with surgical critical illnesses № J. Liver dysfunction is more common in critically ill patients and more difficult to manage. Patients with long-term PN can be complicated by hepatic steatosis, biliary sludge and cirrhosis.IJ Observations of postoperative patients found that the addition of fish oil to PN resulted in significantly lower liver function indicators on postoperative day 6 than in patients on long-chain fatty acids (LCT). In children with short bowel syndrome who developed severe cholestasis and abnormal liver function with long-term use of LCT, switching to PN preparations containing fish oil resulted in improvement in symptoms of cholestasis and normalization of liver function after 8 weeks¨0|. Supplementation of ARDS patients with pharmacological doses of (fish oil rich in) EPA, DHA, and antioxidant substances can increase antioxidant levels in the body, prevent lipid peroxidation damage, reduce the number of neutrophils in bronchoalveolar lavage fluid, decrease pulmonary vascular resistance and alveolar permeability, thereby improving gas exchange and lung function, shortening the time of ventilator application and ICU stay, and reducing organ function further damage. A large sample, multicenter, RcT study from Europe showed that the application of EN supplemented with fish oil and antioxidant vitamins significantly reduced the duration of mechanical ventilation and ICU stay and improved 28-d survival rates’6|. Ecological immunonutrition was first proposed by the Swedish scholar Bengmark and was also called microecological nutrition, which is an extension of the concept of immunonutrition. The concept of ecological immunonutrition has further expanded the concept of nutritional therapy to improve and maintain the intestinal function of patients through rational nutrition, reduce bacterial and/or endotoxin translocation, and thus prevent the occurrence of MODS. The fish oil’s lung and liver function in critically ill patients. The protective effect of fish oil on lung and liver function in critically ill patients, in turn, allows the extension of nutritional conditioning therapy for organ function to organs other than the intestine. Nutritional conditioning therapy has evolved over the past 20 years, from the initial generation of ~ state. Thanks to conditioning therapy, it has gradually expanded to include conditioning therapy for inflammation and immune response, as well as conditioning therapy for vital organ functions such as intestinal tract, lung and liver. Nutritional conditioning therapy has become an important part of the treatment of critically ill patients, and has achieved significant clinical efficacy especially in surgically critically ill patients. Both metabolic conditioning therapy and conditioning therapy for immune response and organ function still have more limitations, and although many clinical issues still need to be addressed, the role of nutritional conditioning therapy in critically ill patients has become increasingly evident. With further research and the application of more and more new nutrients, nutritional conditioning therapy is expected to play a greater role in the treatment of critically ill patients.