Nutritional support for critically ill patients includes enteral nutrition, parenteral nutrition and both shared. Depending on the patient’s condition, the route of enteral nutrition can be performed by nasogastric tube, nasojejunal tube, percutaneous endoscopic gastrostomy, percutaneous endoscopic jejunostomy or intraoperative gastrostomy.1. The transnasogastric route, commonly used for patients with normal gastrointestinal tract function, non-comatose and patients who can transition to normal oral diet by short time nasal feeding, has the advantage of being simple and easy, but has certain disadvantages, such as reflux, misaspiration, However, there are certain disadvantages, such as increased incidence of reflux, misaspiration, sinusitis, and upper respiratory tract infection.2. Patients with severe illness who do not tolerate transgastric nutrition or have a high risk of reflux and misaspiration are advised to choose jejunum nutrition. Percutaneous endoscopic gastrostomy is a percutaneous gastrostomy under the guidance of fiberoptic gastroscope, and the nutrition tube is placed into the gastric cavity, with the advantages of removing the nasal tube, reducing the complications of nasopharyngeal and upper respiratory tract infections, and allowing long-term retention of the nutrition tube, which is suitable for critically ill patients who cannot eat for a long time and have good gastric emptying, such as coma and esophageal obstruction. 3. The advantage of long-term tube placement is that in addition to reducing nasal and upper respiratory tract infection complications, it also reduces the risk of reflux and misaspiration. Gastroduodenal decompression can be performed while feeding, which is especially suitable for critically ill patients who have the risk of misaspiration and need gastroduodenal decompression. Parenteral nutrition can be infused through peripheral veins as well as central veins. Central venous routes include the subclavian vein, internal jugular vein or via the peripheral central venous catheter route.