I. Infectious complications. 1.Aspiration pneumonia: In enteral nutrition support, the sudden appearance of respiratory inflammation or respiratory failure after aspiration occurs is called aspiration pneumonia, which is its most serious complication and is commonly seen in young children, elderly people and patients with impaired consciousness. The clinical manifestations of the patient include dyspnea, shortness of breath, wheezing, irritability, increased heart rate, and X-ray manifestations of speckled shadows in the lower lobe of the lung. The clinical symptoms and prognosis of aspiration pneumonia depend on the amount and nature of the inhaled nutrient solution. Acute pulmonary edema can occur within seconds if large amounts of gastrointestinal nutrient solution are suddenly inhaled into the trachea; the lower the pH of the nutrient solution, the more severe the damage to the lungs. Patients receiving enteral nutrition support via nasal feeding are much more likely to develop aspiration pneumonia than those receiving enteral nutrition support via gastrostomy or jejunostomy. Preventing gastric contents retention and reflux is the fundamental to prevent aspiration pneumonia. Once a patient is found to have signs of aspiration of gastric contents, (1) immediately stop the infusion of enteral nutrition solution and aspirate the contents; (2) immediately perform endotracheal suction; (3) if food particles enter the trachea, immediately perform tracheoscopy and remove them. (4), switch to parenteral nutrition, input a certain amount of albumin to reduce pulmonary edema; (5), perform mechanical ventilation support if necessary; (6), encourage the patient to cough and cough up the misaspirated fluid; (7), apply antibiotics to prevent and control pulmonary infections, and apply glucocorticoids if necessary to improve symptoms. 2.Nutrition fluid contamination: clinically, nasogastric tube is commonly used for gastrointestinal nutrition, and when the tube is inserted, the pharyngeal bacteria may be brought into the stomach and multiply and grow in the stomach, which may lead to enteritis, diarrhea and even more serious systemic infection. Nutrient solution and pipeline instruments may also be contaminated when dispensing and replacing the pipeline, mainly because the operation does not meet the standard. Local pipelines are not cleaned in time, and the long exposure time of nutrient solution in the air is also an important part of nutrient solution contamination. Generally speaking, the nutrient solution can be kept at room temperature for 12 hours without bacterial growth. During the configuration of nutrition solution and intubation of enteral nutrition support, the operation specification should be strictly observed to avoid contamination caused by irregular operation. Second, psychosomatic complications. Enteral nutrition is usually administered by nasogastric tube, which is not easily accepted by some patients. Patients may feel thirsty, lose their sense of taste or feel abnormal taste of nutrition solution, which may cause patients’ tolerance to gastrointestinal nutrition support to decrease. Because of the loss of the sensation of chewing and swallowing food in tube feeding patients, the chewing movement is limited and they feel hungry after seeing food. Due to the presence of nasogastric tube, patients often breathe through the mouth, causing dry mouth and runny nose. Encourage nasal breathing, improve the way of placing the tube and the quality of the tube. Add some condiments to the nutritional solution to give it a special delicious taste. Patients should be encouraged to chew and move more when their condition allows to meet the psychological requirements.