Intestinal obstruction

　　The main pathophysiological changes in intestinal obstruction are distension, loss of body fluids and electrolytes, and infection and toxicosis. The severity of these changes varies with the height of the obstruction site, the duration of obstruction, and whether there is a blood supply obstruction in the intestinal wall.

　　(1) Intestinal distension

　　During mechanical intestinal obstruction, the intestinal lumen above the obstruction swells due to the accumulation of fluid and gas. The first response of the intestinal segment to obstruction is to enhance peristalsis, which causes intestinal colic. At this time, the upper esophageal sphincter relaxes reflexively, and the patient unknowingly swallows a large amount of air during inhalation, so 70% of the accumulated gas in the intestinal lumen is air swallowed, most of which is nitrogen, which is not easily absorbed by the gastrointestinal tract. The remaining 30% of the accumulated gas is produced by the neutralization of acid and alkali in the intestinal tract and the fermentation action of bacteria, or diffused into the intestinal lumen from CO2, H2, CH4, and other gases. The total amount of saliva, gastric juice, bile, pancreatic juice, and intestinal fluid secreted by the digestive tract of a normal adult per day is about 8L, most of which is absorbed by the small intestinal mucosa to maintain fluid balance. During intestinal obstruction, a large amount of fluid and gas accumulate in the proximal part of the obstruction, causing intestinal distension. The distension can inhibit the absorption of water by the intestinal mucosal wall, and then stimulate its increased secretion. As a result, the amount of fluid in the intestinal lumen accumulates more and more, causing progressive exacerbation of intestinal distension. In simple intestinal obstruction, the pressure inside the intestinal tract is generally low, usually less than 8cmH2O at first.

　　As the duration of obstruction prolongs, the pressure inside the intestinal tract can even reach 18cmH2O. The average pressure inside the intestinal lumen during colonic obstruction is usually more than 25cmH2O. During colonic obstruction, the average pressure inside the intestinal lumen is often above 25cmH2O, even reaching as high as 52cmH2O. The increase in intestinal tract pressure can lead to venous return obstruction in the intestinal wall, causing congestion and edema of the intestinal wall. Permeability increases. Continuous increase in intestinal tract pressure can lead to blood flow blockage in the intestinal wall, turning simple intestinal obstruction into strangulated intestinal obstruction. Severe intestinal distension can even raise the diaphragm, affecting the patient's respiratory and circulatory function.

　　(Two) Loss of body fluids and electrolytes

　　During ileus, intestinal distension can cause reflex vomiting. In high-position small bowel obstruction, vomiting is frequent, and a large amount of water and electrolytes are excreted from the body. If the obstruction is located at the pylorus or upper segment of the duodenum, excessive gastric acid is vomited, which is prone to produce dehydration and alkalosis with low chloride and potassium. If the obstruction is located at the lower segment of the duodenum or the upper segment of the jejunum, there is a severe loss of bicarbonate. In low-position ileus, although vomiting is not as common as in high-position ileus, due to the decreased absorption function of the intestinal mucosa, the amount of secretions increases. A large amount of fluid accumulates in the intestinal lumen above the obstruction, sometimes up to 5 to 10L, containing a large amount of sodium bicarbonate. Although these fluids are not excreted from the body, they cannot enter the blood and are equivalent to fluid loss. In addition, excessive intestinal distension affects venous return, leading to intestinal wall edema and plasma leakage. In strangulated ileus, the loss of blood and plasma is particularly severe. Therefore, patients often experience dehydration with oliguria, azotemia, and acidosis. If dehydration persists, the blood becomes further concentrated, leading to hypotension and hypovolemic shock. Hypokalemia caused by potassium loss and not eating can lead to ileus, which further aggravates the development of ileus.

　　(Three) Infection and sepsis

　　Normal intestinal peristalsis causes the contents of the intestines to move forward and be renewed constantly, therefore the small intestine is sterile, or only contains a very few bacteria. In simple mechanical small bowel obstruction, even if there are bacteria and toxins in the intestines, they cannot pass through the normal intestinal mucosal barrier, so the harm is not great. If the obstruction turns into strangulated ileus, initially, venous blood flow is blocked, and the affected intestinal wall exudes a large amount of blood and plasma, further reducing blood volume. Subsequently, arterial blood flow is blocked, accelerating ischemic necrosis of the intestinal wall. The fluid in the strangulated intestinal lumen contains a large number of bacteria (such as Clostridium botulinum, Streptococcus, Escherichia coli, etc.), blood, and necrotic tissue. The toxins of bacteria, as well as the decomposition products of blood and necrotic tissue, all have extremely strong toxicity. When this fluid enters the peritoneal cavity through a ruptured or perforated intestinal wall, it can cause severe peritoneal irritation and infection. After being absorbed by the peritoneum, it can cause sepsis. Severe peritonitis and sepsis are the main causes of death in ileus patients.

　　In addition to the above three main pathophysiological changes, strangulated ileus often also involves bleeding in the intestinal wall, peritoneum, and intestinal lumen. The longer the strangulated intestinal loop, the greater the blood loss, which is also one of the causes of death in ileus patients.

　　The common symptoms of ileus are abdominal pain, vomiting, abdominal distension, and cessation of defecation and flatus.

　　(1) Abdominal pain: It is characterized by intermittent colicky pain. Obstruction of the jejunum or upper segment of the ileum occurs every 3 to 5 minutes, while obstruction of the ileum terminal or large intestine occurs every 6 to 9 minutes. Pain is relieved during the interval between attacks, and colicky pain is accompanied by hyperactive bowel sounds. Bowel sounds are high-pitched. Sometimes, the sound of gas passing through water can be heard. Paralytic ileus may not present with abdominal pain, and high-position small bowel obstruction may not be severe. Middle or low-position ileus presents with typical severe colicky pain, located around the umbilicus or indeterminate. Each attack of colicky pain can last from several seconds to several minutes. If intermittent colicky pain changes to continuous abdominal pain, it should be considered that it has developed into strangulated ileus.

　　(2) Vomiting: After obstruction, the retrograde peristalsis of the intestinal tract causes vomiting in patients. Initially, the vomit is gastric contents, followed by intestinal contents. In cases of high-position small bowel obstruction, the cramps are not severe, but vomiting is frequent. In cases of middle or distal small bowel obstruction, vomiting occurs later, and in cases of low-position small bowel obstruction, the vomit may sometimes appear 'faeces-like' due to the retention of intestinal contents, excessive growth of bacteria, and decomposition of intestinal contents.

　　(3) Abdominal distension: It often occurs in the late stage. High-position small bowel obstruction is not as obvious as low-position obstruction, and colonic obstruction rarely occurs due to the presence of the ileocecal valve, so abdominal distension is obvious. In cases of strangulated intestinal obstruction, the abdomen is asymmetrically distended, and enlarged intestinal loops can be felt.

　　(4) Stopping of flatus and defecation: Generally, patients with intestinal obstruction stop defecating and passing flatus through the anus. However, in cases of mesenteric vascular thrombosis and intussusception, diarrhea or bloody mucus can be excreted. Patients with colon tumors, diverticula, or gallstone obstruction often have black stools.　

　　Intestinal obstruction is a relatively common complication after acute appendicitis, and the causes include:

　　1. Local inflammation, trauma, bleeding, foreign bodies, etc., cause intestinal adhesion, formation of bands, and traction compression of the intestinal tract;

　　2. Drainage tubes accumulate in the intestinal tract;

　　3. Intestinal paralysis, postoperative bed rest, etc., can worsen intestinal adhesion.

　　The key to prevention is to eliminate the impact of these factors on the body. Drainage tubes, as foreign bodies, are often the most common cause of intestinal adhesion and obstruction, while simple inflammation does not lead to serious consequences. Therefore, the author believes that there is no need to place drainage tubes at all [2]. Some people worry that postoperative abdominal effusion, abscess, and fecal fistula cannot be treated, but there is no need to worry at all. As long as the operation and postoperative treatment are handled properly, intestinal obstruction can be avoided. Otherwise, it is a lack of trust in one's own surgery. In addition, appendiceal abscess can be treated surgically after the improvement of anti-inflammatory treatment. The main thing is to master the surgical criteria, clean the talcum powder on the surgical gloves, and avoid bleeding in the abdominal cavity as much as possible. The pus scab is inflammatory fibrin, and the main element of adhesion should be removed cleanly. When closing the abdominal cavity, ensure that the peritoneum is flipped and sutured properly to prevent adhesion with the intestinal tract. It is sufficient to flush the pus clean. Appendicitis mainly causes intestinal paralysis, and intestinal paralysis is prone to secondary intestinal adhesion and obstruction. The most important thing after surgery is to get the intestines moving. As long as the intestines are active, the possibility of intestinal obstruction occurring is greatly reduced. Postoperative routine treatment includes the use of paraffin oil, abdominal massage, and encouragement of early ambulation. Pay attention to the postoperative few cases of diarrhea, which are mainly caused by stimulation of the rectum. The actual intestinal paralysis has not been relieved, and appropriate stimulation of the intestines is still needed. In this way, we can take precautions in advance, and when obstruction actually occurs, we can补救. This not only increases the patient's pain but also wastes medical resources.

　　一．实验室检查：

　　1.血红蛋白及白细胞计数?肠梗阻早期正常。梗阻时间较久，出现脱水征时，则可以发生血液浓缩与白细胞增高。白细胞增高并伴有左移时，表示肠绞窄存在。

　　2.血清电解质(K、a、Cl)、二氧化碳结合力、血气分析、尿素氮、血球压积的测定都很重要。用以判断脱水与电解质紊乱情况。及指导液体的输入。

　　3.血清无机磷、肌酸激酶及同工酶的测定对诊断绞窄性肠梗阻有重要意义。许多实验证明，肠壁缺血、坏死时血中无机磷及肌酸激酶升高。

　　二．对肠梗阻最有帮助的特殊检查是腹部平片与钡灌肠。直立位腹部平片可显示肠拌胀气，空肠粘膜的环状皱襞在肠腔充气时呈“鱼骨刺”样，结肠可显示结肠袋，肠腔充气的肠拌是在梗阻以上的部位。小肠完全性梗阻时，结肠将不显示。左侧结肠梗阻，右侧结肠将有充气。低位结肠梗阻时，左半结肠可以有充气。钡灌肠可用于疑有结肠梗阻的病人，它可显示结肠梗阻的部位与性质。但在小肠急性梗阻时忌用胃肠钡剂造影的方法，以免加重病情。水溶性造影剂的安全性要大得多。B超检查虽然简便，但因肠拌胀气，影响诊断的效果，而CT诊断的准确性优于B超，能诊断出明显的实质性肿块或肠腔外有积液，有时腹部CT还能发现造成肠梗阻的病因和病变部位，为手术提供重要的信息。

　　肠梗阻最好不要吃哪些食物1. It is not advisable to eat gas-producing foods such as milk, soy milk, and foods rich in rough fiber such as celery, soybean sprouts, onions, etc. 2. Avoid foods with long dietary fiber and gas-producing foods before surgery, such as celery, cabbage, rapeseed, radish, potato, sweet potato, soybeans, and broad beans. After surgery, avoid greasy, coarse, and fishy foods such as fatty meat, animal internal organs, brown rice, dog meat, lamb, beef, smoked fish, etc. 3. Avoid coarse foods: After 3 to 4 days of surgery, when the anal exhaust is released, it indicates that the intestinal function begins to recover. At this time, a small amount of liquid can be given, and after 5 to 6 days, it can be changed to low-residue semi-liquid diet. Avoid eating chicken, ham, pigeon meat, and soups of various vegetables. Even if this food is cooked very soft, one should not be in a hurry. 4. Avoid greasy foods: Even after the 10th day, when the body can tolerate soft rice, greasy foods should not be eaten early, such as mother chicken soup, meat soup, lamb, fatty meat, beef bone soup, and turtle soup. 5. Avoid foods that cause hair growth: Even after the suture is removed after surgery, it is necessary to avoid eating dog meat, lamb, sparrow meat, sparrow eggs, dried bamboo shoots, scallions, pumpkin, beef, coriander, smoked fish, smoked meat, chili, chives, garlic sprouts, and sea cucumber, etc. 6. The determination of serum inorganic phosphorus, creatine kinase, and isoenzymes is of great significance for the diagnosis of strangulated intestinal obstruction. Many experiments have shown that when the intestinal wall is ischemic and necrotic, the levels of inorganic phosphorus and creatine kinase in the blood increase. 7. The determination of serum electrolytes (K, Na, Cl), carbon dioxide binding power, blood gas analysis, blood urea nitrogen, and hematocrit is very important. It is used to judge the condition of dehydration and electrolyte disorder and guide the administration of fluids. 8. 1. Hemoglobin and white blood cell count? In the early stage of intestinal obstruction, the blood is normal. If the obstruction time is long and signs of dehydration appear, blood concentration and white blood cell count may occur. When the white blood cell count increases and is accompanied by left shift, it indicates that intestinal strangulation exists. 9. 1. Laboratory examination: 10. What kinds of laboratory tests do you need for intestinal obstruction? 11. 5

　　What kind of food is good for the body when suffering from intestinal obstruction: 1. After one week of surgery, semi-liquid food can be eaten, such as noodles, wontons, millet and red bean porridge, buns, bread, soda crackers, braised tofu, steamed fish, braised fresh vegetable ends, etc.; 2. Foods that are easy to digest and promote defecation, such as vegetables: kelp, pork blood, carrots, etc., fruits: hawthorn, pineapple, papaya, etc.; eating more fibrous foods such as various vegetables, fruits, brown rice, whole grains, and beans can help defecate, prevent constipation, stabilize blood sugar, and reduce blood cholesterol; 3. It is advisable to eat light and nutritious liquid foods, such as congee, vegetable soup, lotus root starch, egg flower soup, noodles, etc.; 4. It is advisable to eat processed or finely cooked foods to facilitate mastication and digestion. One to two whole eggs can be eaten per week. Dairy products and their products, root and tuber crops, meat, fish, beans, eggs, vegetables, fruits, and oils should be consumed in a variety of ways to fully obtain various nutrients; 5. It is advisable to eat foods rich in protein and iron, such as lean meat, fish and shrimp, animal blood, animal liver and kidney, egg yolk, bean products, and dates, green vegetables, sesame paste, etc.; 6. Choose vegetable oils, and use more methods such as boiling, steaming, cold plate, frying, roasting, braising, and stewing for cooking; avoid foods high in cholesterol such as fatty meat, internal organs, fish eggs, butter, etc.

　　The treatment of intestinal obstruction includes non-surgical treatment and surgical treatment. The choice of treatment method is determined by the cause, nature, location, and severity of the condition, as well as the overall condition of the patient. Regardless of the type of treatment adopted, the first step is to correct the water, electrolyte, and acid-base disorders caused by the obstruction and improve the patient's overall condition.

　　The principles of treating intestinal obstruction: ① Correct water, electrolyte, and acid-base balance disorders; ② Supplement circulatory blood volume; ③ Reduce intraluminal tension; ④ Use antibiotics to prevent and treat infection; ⑤ Remove the cause of obstruction and restore intestinal patency; ⑥ Operatively handle intestinal strangulation.

　　Non-surgical treatment

　　(1) Gastrointestinal decompression therapy: The gastrointestinal decompression removes the accumulated gas and fluid at the upper end of the obstruction, reduces intraluminal tension, is beneficial for improving the blood circulation of the intestinal wall, alleviating systemic poisoning symptoms, and improving respiratory and circulatory function. Effective gastrointestinal decompression can achieve the purpose of relieving obstruction in simple intestinal obstruction and paralytic intestinal obstruction, and is also a good preoperative preparation for those who need surgery;

　　(2) Fluid therapy: The focus is on correcting water, electrolyte, and acid-base balance disorders. During intestinal strangulation, due to the loss of a large amount of plasma and blood, after appropriate fluid resuscitation, whole blood or plasma should be administered;

　　(3) Nutritional support therapy: During intestinal obstruction, surgery or non-surgical treatment may last for a considerable period of time during which patients cannot eat, so nutritional support is very important. General peripheral venous infusion usually does not meet the requirements of nutritional support, and total parenteral nutrition can be used, which means that the necessary nutrients for the body are infused through the venous route. The use of total parenteral nutrition during intestinal obstruction can serve as preoperative preparation, as well as support treatment for non-surgical treatment or support treatment after surgery when early eating is not possible. If the intestinal obstruction is resolved and the intestinal function is restored, it is best to start taking oral food as soon as possible. Patients who cannot eat normal food can consume elemental diets;

　　(4) Antibiotic therapy: During intestinal obstruction, bacteria can rapidly multiply in the upper intestinal lumen above the obstruction. Intestinal obstruction patients should use antibiotics that target both aerobic and anaerobic bacteria.

　　Surgical Treatment

　　For strangulated intestinal obstruction, after short-term preoperative preparation and sufficient blood volume, surgery should be performed as soon as possible. However, if shock is present, it is safer to wait until the shock is corrected or improved before surgery. Sometimes, it is estimated that there is already necrotic bowel, and the shock is difficult to correct in the short term. In this case, both anti-shock treatment and surgery should be performed simultaneously, resecting the necrotic bowel segments, so that the shock will subside.

　　The surgical aim of intestinal obstruction is to relieve the cause of obstruction and restore intestinal patency. However, the specific surgical method should be determined according to the cause, location, nature, course of the disease, and general condition. For adhesive intestinal obstruction, there are many surgical methods with varying degrees of difficulty. The easier cases may only require the incision of a fibrous band, while the more difficult cases may make the surgeon find it difficult to operate, forcing the surgeon to have to resect a large amount of intestinal loops, or perform a short-circuit anastomosis, or perform intestinal stoma decompression surgery to alleviate the symptoms of obstruction. In more severe cases, the surgery may have to be terminated due to excessive adhesion and the inability to perform any other operations, which shows that dealing with adhesive intestinal obstruction surgery is not an easy task and requires perfect surgical plans and good technical preparation before the operation.