1, Clinical data From September 2005 to December 2007, the author’s unit admitted three cases of severe burns complicating Superior Mesenteric Artery Compression Syndrome (SMAS), two male and one female, aged 14-25 years. All were thermal burns. The total burn area was 65%~90%, of which 50%~60% TBSA of degree Ⅲ. Pre-injury emaciation, poor body condition, sepsis in 2 cases in 7~10d after injury, and SMAS in 13~14d. Clinical manifestations: epigastric fullness, eructation, and projectile vomiting shortly after eating, with gastric contents or gastric juice mixed with bile in the amount of 1,500~2,770 ml/24 h. Ultrasound of abdomen suggested gastric dilatation, and X-ray showed that the stomach was dilated, with the gastric juice mixed with bile. Suggestive of gastric dilatation, visualized with panaglutamide under X-ray: gastric macrocystic type, duodenal dilatation, no peristaltic waves seen in the stomach and duodenum, developer can enter the horizontal segment of the duodenum, not entering the small intestine. According to the typical clinical manifestations, and X-ray, the diagnosis of SMAS was confirmed. 2. Treatment of superior mesenteric artery compression syndrome (1) Immediate water fasting. (2) Keep nasogastric tube and continuous gastrointestinal decompression. When the drainage fluid is <30~50ml/24h, gastrointestinal decompression is stopped, and a small amount of liquid food is fed through the mouth, and the nasogastric tube is removed when no discomfort is observed for 1~2 days. At this time, the oral diet and the duodenal tube pumped into the nutritional fluid coexisted, and the patient ate without discomfort. (3) Replace the spiral nasogastric tube (CH10 145cm, OD 3.33mm) with Olympus 160 electronic gastroscope. All three cases in this group were left with nasoenteric tube within 6 hours after injury, and in the complication of SMAS, its distal end was confirmed to be in the duodenal bulb by X-ray radiography, so it was reset so that the distal end spanned the ligament of Treitz to the distal part of duodenal compression site, which was confirmed by X-ray, and then nutrient solution was pumped in with a feeding pump. Combined with parenteral nutrition, the total daily calories were calculated according to Curreri's formula: 104.6kJ × body weight (kg) + 167.4kJ × burned area, which was 15065KJ~20819kJ for the three cases in this group, and the calories could be completely supplied by enteral nutrition after parenteral nutrition was used for 8~12d, at which time the nasoenteric tube could be removed. (4) Take prone position in the turning bed, 2~3h/times, 3 times/24h, (5) Control infection and sepsis, strengthen the maintenance of organ function and systemic supportive therapy. 3.Results All 3 cases of SMAS were cured by conservative treatment, and there was no 1 case of complication of stress ulcer. Nasogastric tube was left in place for 7~13d, and nasoenteric tube was left in place for 25~32d, and they were discharged from the hospital after 42~65d of treatment. 4, Discussion The etiology of SMAS complicated by severe burns is clear, due to high metabolism after burns, nutritional consumption increases, lipolysis increases, mesenteric and retroperitoneal fat decreases, so that the fat pad between the abdominal aorta and the superior mesenteric artery becomes thin, and the angle of the two becomes small, and the duodenal transverse section is located in the angle of the sandwich, and in addition to the long term lying down, due to the superior mesenteric artery pull, the angle of the sandwich is further reduced so the superior mesenteric artery compresses the subsequent duodenal artery and the duodenal artery, which is the most important part of the disease. The superior mesenteric artery compresses the duodenum, causing SMAS. In the past, there were many reports of continuous gastrointestinal decompression with indwelling nasogastric tube, but the method of indwelling both nasogastric and nasoenteric tubes "double-tube" has not been reported. In this group, all three cases were "two-pronged", and enteral feeding was implemented at the same time of gastrointestinal decompression, which protected the intestinal mucosa, prevented the occurrence of enteric infections, provided a certain amount of calories, and shortened the time of parenteral nutrition. The amount of nutrient solution pumped in by feeding pump, from small to large, can reduce the related complications, and there was no case of interruption of enteral nutrition due to complications in this group. Therefore, the "two-pronged" treatment of SMAS is safe and effective. In the prone position, the angle between the superior mesenteric artery and the abdominal aorta increases by pulling the superior mesenteric artery, which reduces the compression on the transverse duodenal segment and relieves the clinical symptoms. Turned bed therapy for extensive burns favors the prone position. Therefore, as long as the patient's condition allows to prolong the prone position as much as possible, three cases were treated in the prone position, the clinical symptoms were relieved, and no accident occurred in one case, which was safe and effective. Severe burns are in a hypermetabolic state, and on top of this after complications of sepsis, resting energy expenditure (REE) is further elevated and lasts longer, and this strong hypermetabolic response that promotes in vivo proteolysis and inhibits the utilization of sugars and fats can cause the body to fall into a negative nitrogen balance and malnutrition rapidly, leading to complications [2]. This may explain the predisposition to SMAS after complicated sepsis. Hypermetabolism after severe burns leads to nutritional depletion and complication of SMAS, therefore, those who are thin and in poor physical condition before the injury are regarded as the high-risk group prone to complications, and attention should be paid to calorie intake to prevent and control sepsis and to prevent the occurrence of SMAS. For those suspected of SMAS, X-ray imaging should be done as early as possible to confirm the diagnosis, and treatment should be done as early as possible once the diagnosis is confirmed.