[Abstract] Nutritional support has an important impact on the prognosis of neurocritically ill patients. Nasogastric tube as the traditional way to give enteral nutrition is widely used in clinical practice, but it is often accompanied by complications such as misaspiration, catheter displacement and infection. Long-term application of parenteral nutrition is prone to liver and kidney failure, and is more expensive, less effective, and relatively more costly to care for. Percutaneous endoscopic gastrostomy (PEG) is a technique that has been gradually accepted and widely used in clinical practice in recent years to provide ideal enteral nutrition support for patients with common neurocritical conditions and improve their prognosis. With the improvement of PEG operation technique and the gradual recognition of its complications, PEG technique has become increasingly mature and becomes a relatively ideal way for long-term application of enteral nutrition in neurocritical patients at present. [Keywords] Percutaneous endoscopic gastrostomy; neurocritical illness; enteral nutrition Patients with neurocritical illness after stroke, craniocerebral trauma and craniocerebral surgery often present with dysphagia, because the cortical areas of the brain play an important role in conscious or unconscious swallowing movements, and swallowing dysfunction also occurs when the brainstem and posterior group of brain nerves are affected. Although most brain injuries in neurocritical patients are irreversible, the main causes of death in patients are inadequate cerebral perfusion, imbalance of nutrient metabolism, and secondary brain damage brought about by inflammatory reactions. Therefore, it is particularly important to address the eating disorders caused by dysphagia in neurocritically ill patients and to provide reasonable and effective nutritional metabolic support for the prognosis of patients. In neurologically ill patients, the body is in a state of stress, and adequate nutritional support will reduce the rate of death and disability due to this state of stress. At present, there are three main types of nutrition support: 1) simple parenteral nutrition; 2) simple enteral nutrition; 3) a combination of the two methods. Parenteral nutrition is more traditional and widely used, and it can directly and effectively provide nutritional support for the body’s needs. However, the long-term application of parenteral nutrition will increase the burden on organs and will easily cause organ failure, among which liver and kidney failure are the most common. At the same time, long-term parenteral nutrition also increases the cost of care and medical treatment. Therefore, parenteral nutrition is not suitable for patients who need long-term nutritional support. Enteral nutrition can promote the recovery of GI function, maintain the intestinal mucosal barrier, and reduce metabolic complications, thereby improving the nutritional status of patients, except that there are great differences in the feeding methods. The European Society for Parenteral Enteral Nutrition (ESPEN) Guidelines for Enteral Nutrition states that for elderly patients (age >65 years) suffering from severe neurological dysphagia, enteral nutrition (EN) can ensure their energy and nutrient supply and maintain or improve their nutritional status (Grade A). The 2011 edition of the Consensus on Indications for Nutritional Support in Neurological Diseases suggests that enteral nutrition support is recommended for patients with stroke and craniocerebral trauma with dysphagia, with early initiation of feeding at early onset. Traditional enteral nutrition is mainly fed via nasogastric tube (NGT), which is easy to operate and acceptable to patients. However, prolonged application also causes complications such as nausea, acid reflux, oral and nasal mucosal damage, reflux aspiration, and decreased well-being of patients. In recent years, percutaneous endoscopic gastrostomy (PEG) has been widely used abroad in patients with severe stroke and craniocerebral trauma because of its effectiveness and simplicity, and has achieved good results. The current application of PEG in neurosurgical intensive care patients is reviewed. 1.Operation method Gauderer and Ponsky first applied PEG to the clinic, and after years of improvement, PEG has been more often used in neurosurgical intensive care patients. The operation points such as: (1) the patient to take the supine position, before carrying out PEG first blow 500ml of air in the stomach, and take abdominal plain film for calibration; (2) the puncture point is generally selected near the gastric angle cut, to the gastric greater curvature and gastric lesser curvature distance equal, the point is the best puncture point, but also according to the abdominal wall fluoroscopy to see the light with the hand palpation feel the location of the gastroscope to determine the appropriate scope of the operation, which greatly improves the (3) After the puncture point is selected, a small 0.5-25 px incision is made in the skin with a scalpel, and then a 14-G needle with a jacket tube is inserted into the abdominal wall. After the puncture needle was seen under the gastroscope, the guidewire was inserted into the outer casing, and a captive sleeve was inserted through the gastroscopic biopsy tube at the same time, and the guidewire was firmly set and then withdrawn from the oral cavity together with the gastroscope. The PEG catheter is then pulled out of the abdominal wall puncture site. The patient can eat through the tube after 24 hours; (4) After the puncture site is determined, the puncture can be performed with the “safe tract” method first. Since some patients have anatomical structures in the anterior part of the stomach, it is recommended to use a 25-G needle and syringe to inject 1-2 ml of saline at the puncture site first. This will increase the safety and reliability of the puncture. 2. Replacement treatment PEG is a feeding technique applied to long-term enteral nutrition, and the PEG tube may become obstructed, ruptured, or displaced after a period of placement. There are potential complications during the replacement operation, such as peritonitis and intestinal perforation. Due to the lack of uniform opinions as well as guidelines from the international community, the safety of PEG tube replacement is improved clinically by improving some steps, including early understanding of the high-risk operation method, selection of the appropriate replacement method, and confirmation of the correct position of the tube. Routine replacement of PEG tubes is not recommended at this time unless there is catheter obstruction or displacement or an optional procedure recommended by the manufacturer. Studies have shown that in patients with loss of consciousness or with neuromuscular disease, replacement within 10-14 days from the time of tube placement raises the risk of complications. Routine PEG tube replacement with a “cut-and-push” balloon PEG tube has also been used to reduce the risk associated with tube replacement, although no large sample has been studied to confirm this. The stress state of neurological patients is mainly manifested as: 1. high energy metabolism and high catabolic state; 2. high blood sugar state; 3. acute phase reaction state; 4. immunosuppression state. The high-energy, high-catabolic state is mainly due to the disruption of the hypothalamic-pituitary axis and the sympathetic-adrenal axis. As the hypothalamic-pituitary axis as well as sympathetic-adrenal axis are affected in the stress state, patients have increased secretion of catecholamines, glucagon and other hormones, accelerated energy metabolism, elevated blood glucose and increased protein consumption, therefore, enteral nutritional support needs to be provided as early as possible to replenish calories and proteins, thus reducing the risk of burden balance on the prognosis of patients, and attention should be paid to blood glucose control, as excessive blood glucose will aggravate High blood glucose can aggravate the onset of cerebral ischemia and aggravate cranio-cerebral injury. Secondly, stress activates the inflammatory response of the body, and acute phase response proteins (e.g., fibrinogen, hsCRP, etc.) and cytokines (e.g., TNF, ventricular and plasma IL-1, IL-6, and IL-8) are significantly increased. The neuroendocrine alterations and the increase in cytokines together cause metabolic responses such as cardiovascular hyperdynamics and sodium and water retention. The decreased cellular immune response in severe craniocerebral injury may be related to nutritional deficiencies, increased anti-regulatory hormones, decreased cytokine (IL-2) levels, and insufficient helper T lymphocytes. The activation of inflammatory factors and the suppression of the immune system cause tissue damage and even the development of multi-organ failure (MODS). Therefore, the timely and rational application of nutritional support can maximize the damage to the organism in stressful conditions. How to determine in the first place the need for long-term (>6 weeks) application of PEG to provide enteral nutrition in neurocritically ill patients has been the subject of research.Amy et al. analyzed 375 traumatic brain injury patients with GCS scores <=8< span="">, of whom 269 had RLA scores, 219 had dysphagia symptoms, and 106 did not have RLA scores.110 patients were discharged with a tube and 159 patients were discharged without a tube. The study showed that patients’ age, initial RLA score, tube carrying status, and loss of voice all played a statistically significant role in determining the early stage of performing PEG intubation, and further research and analysis is needed to determine the exact impact. Although nasogastric tube in the traditional sense has the characteristics of simple operation and little trauma, symptoms such as aspiration pneumonia, tube blockage, tube displacement and patient discomfort can occur. PEG operation is relatively simple, safe, convenient, long retention time and less complications, so neurocritical patients who cannot eat through the mouth and have good gastrointestinal function can continue to perform PEG treatment even after discharge, thus improving the quality of survival of patients. Although PEG is an invasive procedure, the success rate of intubation is higher and the possibility of aspiration pneumonia is lower. In a retrospective analysis of 20 PEG patients, the incidence of pulmonary infections was reduced from 65.0% to 15%, and patients’ nutritional status, body mass index, and nutritional indicators were significantly improved and enhanced. Long-term application of PEG has many advantages over NGT, including increased patient comfort, reduced sinusitis, parotitis, nasal cartilage and esophageal erosion, reduced potential for catheter displacement, blockage, and reduced incidence of aspiration pneumonia and reflux esophagitis. In patients with impaired consciousness and dysphagia, there are greater advantages to PEG. Therefore, compared with nasogastric tube, enteral nutrition via PEG is more suitable for neurological intensive patients with swallowing difficulties. 4. Indications, contraindications and common complications of application Indications include: (1) swallowing dysfunction due to cortical impairment; (2) swallowing dysfunction due to tumor in the oral cavity or esophagus; (3) normal swallowing function, but normal feeding cannot meet the body’s needs, such as burns; (4) other, such as chronic diseases, gastric torsion, etc. Contraindications to PEG are inability to pass gastroscopy, inability to survive for more than a few weeks, and inability to swallow. survival time of no more than a few weeks, as well as massive ascites, severe obesity, post subtotal gastrectomy, hepatomegaly, cardiopulmonary failure, etc. Complications have been the focus of attention, mainly including aspiration pneumonia, incisional infection, leakage, perforation, catheter displacement, etc. Among them, aspiration pneumonia is the most common, with an incidence of about 10-22%, and is the most important cause of patient death. Aspiration pneumonia is mainly caused by gastroesophageal reflux after placement of PEG tubes, and the exact mechanism is still unknown. Shinji Nishiwaki et al. conducted a comparative study of 15 patients using semi-solid nutrients and found that feeding with semi-solid nutrients reduced the occurrence of gastroesophageal reflux after PEG tube placement and accelerated gastric emptying, thus replacing solid nutrients with liquid nutrients for patients requiring long-term PEG application. PEG in patients to reduce the occurrence of adsorptive pneumonia. Other complications have also been reported; Hyun et al. reported a 65-year-old male patient with right cerebellar infarction who had recurrent episodes of aspiration pneumonia. The PEG tube was replaced 6 months after placement, and CT and colorectal microscopy after placement of the new tube showed that the tube penetrated the rectum to form a gastrotransverse colonic fistula, and the patient presented with febrile symptoms and signs of abdominal pressure pain. Kenan et al. reported two patients with mediastinal emphysema after PEG placement, which was considered to be caused by an esophageal fistula. In addition, air can enter the mediastinum from the lungs, trachea, neck, abdominal cavity, or retroperitoneal space. Therefore, the use of PEG in clinical practice should be based on the indication to select the right patient. Amer et al. evaluated 187 stroke patients, 33 of whom had PEG placement, and these individuals had a mean age of 65-73 years. patients with NIHSS scores greater than or equal to 12 and with aspiration pneumonia had the best results with PEG tubes. For stroke patients, the NIHSS score with concomitant aspiration pneumonia is the best indication for the application of PEG. PEG, as an established route of enteral nutrition in recent years, is more suitable than the traditional NGT route for neurocritical patients with prolonged coma and dysphagia. The importance of the PEG route has been clearly stated in the 2011 edition of the Consensus on Indications for Nutritional Support in Neurological Diseases. As an invasive procedure, PEG has certain complications, but with the development of technology and increased proficiency in the procedure, the incidence of these complications is decreasing. For neurocritical patients, PEG plays an increasingly important role in improving prognostic outcomes and is the best option for patients who require long-term enteral nutrition support without contraindications. More rigorous prospective studies and more clinical experience are needed in the future.