Secondary peritonitis

　　First, the cause of onset

　　1. Pathogenic cause

　　Secondary peritonitis is often caused by acute lesions of intra-abdominal organs, common causes include:

　　(1) Acute infection: Acute infection of intra-abdominal organs is the most common cause of secondary purulent peritonitis.

　　①Infections of the digestive tract and digestive glands: such as acute appendicitis, Meckel diverticulitis, colonic diverticulitis, necrotizing enterocolitis, acute Crohn's disease, acute cholecystitis, acute pancreatitis, liver abscess, and so on.

　　② Upward infection of female reproductive organs: such as gonococcal salpingitis, postpartum infection, induced abortion, acute salpingitis, etc.

　　③ Umbilical cord infection in infants.

　　④ Empyema can also cause peritonitis.

　　(2) Acute gastrointestinal perforation: when the gastrointestinal tract perforates, digestive juices and blood enter the abdominal cavity, stimulating the peritoneum to cause secondary suppurative infection. Among them, acute appendicitis complicated with perforation is the most common, followed by acute perforation of gastric and duodenal ulcers, less common perforations include worm intestinal perforation, gangrenous cholecystitis, small and large intestinal diverticula, etc., and perforation of gastric cancer and colon cancer can also lead to secondary peritonitis.

　　(3) Strangulated intestinal obstruction: such as intestinal volvulus, closed loop intestinal obstruction, etc., the mucosa of the intestine becomes more permeable due to ischemia, and bacteria in the intestinal lumen seep through the intestinal wall into the abdominal cavity, causing infection.

　　(4) Vascular occlusive diseases: such as mesenteric vascular thrombosis, ischemic colitis, splenic infarction, etc., the large amount of exudate produced during ischemia can stimulate the peritoneum to cause inflammatory changes.

　　(5) Abdominal hemorrhage: spontaneous splenic rupture, splenic aneurysm rupture, liver cancer rupture, abdominal cavity metastatic malignant tumors (such as seminoma) rupture, ectopic pregnancy rupture, ovarian follicle rupture, etc.

　　(6) Trauma: Trauma caused by either blunt or sharp objects can cause damage to organs in the peritoneal cavity. After hollow organs such as the stomach, small intestine, colon, and bladder are pierced, bacterial peritonitis is quickly induced. After the bladder is ruptured, urine stimulation causes chemical peritonitis, which then turns into a bacterial infection. Rupture of solid organs such as liver and spleen, although the stimulation of blood to the peritoneum is mild, peritonitis can also be fatal once infected.

　　(7) Iatrogenic: such as the overflow of intestinal contents during surgery, especially the overflow of colonic contents leading to contamination of the peritoneal cavity; insufficient tightness or leakage of gastrointestinal anastomosis; foreign bodies left in the abdominal cavity; intestinal fistula, bile fistula, pancreatic leakage, and ureteral leakage caused by accidental injury to the intestines, bile ducts, pancreatic ducts, and ureters; recent abdominal cavity hemorrhage or bleeding after surgery, etc.

　　2. Pathogenic bacteria

　　The bacteria causing secondary peritonitis are all common bacterial species on the human intestinal tract and skin surface, which is the bacteriological characteristic of peritoneal cavity infection. In addition, secondary peritonitis is mostly a mixed infection of aerobic and anaerobic bacteria, with an incidence rate of more than 58%.

　　Anaerobic bacteria are most commonly found in Escherichia coli, in addition to Klebsiella pneumoniae, Proteus, Streptococcus faecalis, Gas-forming bacteria, and Pseudomonas aeruginosa, etc. Anaerobic bacteria are commonly found in Bacteroides fragilis. Since aerobic bacteria absorb oxygen from the environment they are in, reducing the redox potential, anaerobic bacteria can grow and reproduce in an anaerobic environment. Anaerobic bacteria can also release enzymes, growth factors, and host response inhibitors that are beneficial for the reproduction of aerobic bacteria. Aerobic bacteria can provide a large amount of vitamin K required for the reproduction of anaerobic bacteria, and their synergistic action greatly increases virulence and pathogenicity. For example, Streptococcus faecalis and Bacteroides fragilis have low pathogenicity, but in mixed infections, there is often a synergistic effect between them, resulting in increased toxicity.

　　Second, pathogenesis

　　The peritoneum is extremely sensitive to various stimuli. After bacteria or gastrointestinal contents enter the abdominal cavity, the body immediately produces a reaction. The degree of inflammatory reaction is related to the strength of the stimulus. For example, when the pH of gastric juice is less than 3.0, the stimulation to the peritoneum is extremely strong, and an acute chemical peritonitis can occur immediately in the case of acute perforation of a gastric ulcer; certain components of bile salts have a strong stimulating effect on the subperitoneal microvessels, and when cholestatic peritonitis occurs, there will be more exudate in the abdominal cavity, and it is prone to concurrent anaerobic bacterial infection; the mesothelial cells of the peritoneum contain plasminogen activator, and when organs or blood vessels are ruptured, the blood in the abdominal cavity is not easy to coagulate. Although the stimulation to the peritoneum is relatively weak, hemoglobin can interfere with the body's immune response, affecting the clearance of bacteria, so it is easy to develop secondary infection.

　　During acute peritonitis, the peritoneum becomes congested and edematous, losing its luster. Subsequently, a large amount of clear serous exudate is produced to dilute the toxins in the abdominal cavity; and a large number of macrophages and neutrophils, as well as biologically active substances and cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and elastase, etc., are elevated; the fibrinogen in the exudate is converted into fibrin and deposited under the action of thrombin released by peritoneal mesothelial cells.

　　With the continuous death of white blood cells, the damage and desquamation of mesothelial cells between the peritoneum and visceral serous membrane, the deposition and coagulation of fibrin, the exudate gradually becomes turbid and becomes pus.

　　The pathological changes of peritonitis depend on: the nature of the infection source, the type of bacteria, the quantity, and the virulence; the defensive ability of the whole body and the local defense ability of the peritoneum; the time and effectiveness of the initial treatment. The development of acute peritonitis is determined by the patient's ability to resist infection, the outcome of the primary focus, and the severity of bacterial infection. It can develop into diffuse purulent peritonitis, or become localized by the wrapping of the intestinal tract and omentum and纤维素 adhesion, or gradually absorb and heal spontaneously, or form an abscess. Diffuse peritonitis often complicates paralytic ileus. In addition to the serous membrane of the intestine itself, i.e., the visceral peritoneum, also becomes congested and edematous, affecting its peristaltic function. The suppression of visceral nerve reflexes, water and electrolyte imbalance, especially hypokalemia, and the secretion disorder of gastrointestinal hormones are all related to the occurrence of paralytic ileus. The widespread congestion of the intestinal tract, the accumulation of digestive juices, and the increased loss of body fluids. Due to the large amount of extravasation in the abdominal cavity and the large amount of fluid accumulation in the intestinal lumen, the extracellular fluid sharply decreases, forming hypovolemic shock and metabolic acidosis. Abdominal distension, elevation of the diaphragm, and difficulty in pulmonary gas exchange further exacerbate acidosis. Due to the reduction in blood volume and shock, renal function is also damaged. Throughout the process, the endocrine system, such as the adrenal glands, also actively participates in the reaction. If not treated promptly and correctly, the condition will further worsen, which can lead to the death of the patient.

　　What complications can secondary peritonitis easily lead to?

　　1. Anemia The peritoneum is severely congested, widely edematous, and exudes a large amount of fluid, causing dehydration and electrolyte disorder. The decrease in plasma protein exacerbates anemia.

　　2. Shock The mesentery has a large area and strong absorption capacity. The large absorption of bacterial toxins can lead to hypovolemic shock and septic shock. The patient may present with weak pulse, low blood pressure, restlessness or apathy, cold sweat, sunken eyes, cold hands and feet, increased and shallow breathing, and body temperature not rising.

　　1. Clinical symptoms

　　1. Abdominal pain

　　Abdominal pain is the most common symptom of secondary peritonitis, and its characteristics are:

　　(1) The onset is sudden, the pain is severe, and it is persistent: once secondary peritonitis occurs, the abdominal pain becomes persistent. Since the peritoneum is innervated by somatic nerves, the abdominal pain is severe. However, due to different causes, the degree of abdominal pain can vary. The abdominal pain caused by chemical peritonitis is the most severe, while the abdominal pain caused by abdominal hemorrhage is the mildest.

　　(2) The initial site and the site of the primary disease lesion are consistent, spreading rapidly, but the abdominal pain is most severe at the site of the primary disease focus: when abdominal diseases lead to secondary peritonitis, the abdominal pain intensifies, and the range can be limited to one place or spread to the entire abdomen. Even if secondary diffuse peritonitis occurs, the pain starts from the site of the primary disease focus, although it spreads to the entire abdomen, the abdominal pain at the site of the primary disease focus is still the most severe.

　　(3) Coughing and turning over can exacerbate the pain, and deep breathing or movement can worsen the abdominal pain, so the patient dare not breathe deeply or turn over.

　　In some cases, the pain caused by peritonitis can be affected by various factors, such as acute perforation of peptic ulcer disease. Initially, due to the overflow of acidic gastric juice, chemical peritonitis is produced, resulting in extremely severe abdominal pain. However, after a large amount of gastric juice has overflowed, the remaining gastric juice decreases, or the perforation is sealed, and there is no longer any overflow of gastric juice. The overflowed gastric juice is diluted by exudate, and the abdominal pain can temporarily subside. After a few hours, if infection occurs, the abdominal pain increases again. For example, in cases of strangulated intestinal obstruction, the pain is also extremely severe and persistent, often masking the abdominal pain caused by peritonitis. In elderly and weak patients, severe illness, weak physique, or postoperative patients, due to poor response, the abdominal pain may not be typical.

　　2. Nausea, vomiting

　　Initially, it is reflexive and relatively mild, and then it tends to become more frequent due to infection and toxicity reactions or secondary paralytic ileus. If peritonitis is secondary to an abdominal infection focus, then the symptoms such as nausea and vomiting that were originally present may become more severe. After the onset of acute peritonitis, due to decreased intestinal peristalsis, patients often have no flatus or defecation. In cases of pelvic peritonitis or rectal irritation by exudate or pus, patients may also have a feeling of坠 and defecation, or they may only be able to pass a small amount of mucous stool, and still feel unwell after defecation.

　　3. Body temperature, pulse

　　Its changes are related to the severity of inflammation. Initially, it is normal, and then the body temperature gradually increases, the pulse gradually quickens. If the original lesion is inflammatory, such as appendicitis, the body temperature has already increased before peritonitis occurs, and it will increase even more after peritonitis. In elderly and weak patients, the body temperature may not increase, and the pulse tends to quicken. If the pulse quickens but the body temperature drops, this is one of the signs of deterioration of the condition.

　　4. Symptoms of infection and toxicity

　　Patients may experience high fever, rapid pulse, shallow breathing, profuse sweating, dry mouth, and further progression of the condition may lead to pale complexion, weakness, sunken eye sockets, dry skin, cold extremities, rapid breathing, cyanosis of the lips, dry tongue with thick coating, weak and thready pulse, sudden rise or drop in body temperature, decrease in blood pressure, confusion or loss of consciousness, indicating severe dehydration, metabolic acidosis, and shock.

　　Secondly, signs

　　1. Compulsive posture

　　Secondary peritonitis is a severe acute abdominal condition, with patients presenting with an acute illness appearance, often groaning, and lying still to avoid exacerbation of abdominal pain, preferring to flex the lower limbs.

　　2. Abdominal signs

　　Significant abdominal distension, weakened or absent abdominal breathing, and worsening abdominal distension are important signs of disease progression. Abdominal tenderness, abdominal muscle tension, and rebound pain are characteristic signs of peritonitis, especially at the site of the primary focus. Abdominal distension and muscle tension vary in degree depending on the cause and the patient's overall condition. In patients with acute perforation of peptic ulcers, due to the strong stimulation of the peritoneum, reflex abdominal muscle rigidity occurs, presenting as a 'wooden board' appearance; in infants, the elderly, or extremely weak patients, abdominal muscle tension may not be obvious and is easily overlooked; in emaciated patients, the abdomen may appear concave, but in cases of peritonitis caused by intestinal obstruction, especially low-position intestinal obstruction, the abdomen becomes distended, and abdominal tenderness is present.

　　During abdominal percussion, gastrointestinal distension presents as tympany. When there is a perforation in the stomach and duodenum, a large amount of gas in the intestines moves to the armpits, causing the liver dullness to decrease or disappear. When there is a large amount of fluid in the abdominal cavity, a shifting dullness can be percussion, and during auscultation, bowel sounds are decreased. In cases of intestinal obstruction, bowel sounds may completely disappear.

　　3. Rectal examination

　　A full and tender anterior rectal fossa indicates that there is already infection or formation of a pelvic abscess in the pelvis. In female patients, the location of the primary focus and the presence of gynecological conditions can also be judged according to the pain on the cervix.

　　This disease is secondary to intra-abdominal lesions and is most commonly caused by acute appendicitis perforation, followed by perforation of gastric and duodenal ulcers, acute cholecystitis perforation, acute hemorrhagic necrotic pancreatitis, intestinal obstruction leading to intestinal necrosis, etc. Abdominal trauma, postoperative complications such as digestive tract anastomotic fistula, and purulent inflammation of female reproductive organs can also cause this disease. Therefore, the key to preventing this disease is to properly handle the primary disease that causes peritonitis, which can minimize the incidence of the disease. When peritonitis occurs and the cause and source are unknown, do not abuse painkillers to prevent masking the condition. Stop eating immediately and seek medical treatment at a hospital with the necessary conditions. For patients with severe peritonitis, once diagnosed, early surgery should be sought under adequate preparation to appropriately handle the primary disease and to clear and drain the peritoneal effusion.

　　1. Blood tests

　　White blood cell counts are generally elevated, and the more extensive the inflammation and the more severe the infection, the more pronounced the increase in white blood cell counts.

　　2. CT scan

　　It is easier to observe than X-ray films and more accurate. CT not only shows common imaging characteristics similar to X-ray films but may also show certain specific imaging manifestations due to different causes of acute peritonitis, such as those originating from gallstones, inflammation, or perforation, where the peritoneal effusion is mainly distributed in the right subhepatic space, right suprahypogastric space, and right paracolic sulcus. Gallstones may be found in the gallbladder or in the aforementioned areas, and there is generally no pneumoperitoneum. Perforation of the posterior wall of a gastric ulcer can lead to generalized peritonitis, often accompanied by effusion and gas in the omental bursa. Perforation of acute appendicitis can lead to localized peritonitis in the lower right quadrant, showing signs of an enlarged appendix with fecaliths or displacement, and inflammation of adjacent fatty tissue, which may even show small bubble signs in the inflammatory area. Therefore, CT examination is helpful in diagnosing abdominal organ lesions and assessing the amount of peritoneal effusion.

　　3. Ultrasound

　　Guiding peritoneal puncture to aspirate fluid or peritoneal lavage can help with diagnosis.

　　4. Rectal examination and culdocentesis

　　If the anterior wall of the rectum is full and painful, it indicates that there is already an infection or a pelvic abscess in the pelvis. Married female patients can undergo a vaginal examination or culdocentesis.

　　5. Laparoscopic exploration

　　Laparoscopic exploration can reach the entire peritoneal cavity and can clearly observe the liver, gallbladder, stomach, duodenum, colon, appendix, uterus and adnexa, bladder, especially for the diagnosis of acute appendicitis, perianal abscess, and pelvic inflammatory lesions, the accuracy rate is higher.

　　Dietary taboos for secondary peritonitis:

　　1. Peritonitis patients should eat more foods that have a cooling and diuretic effect, such as amaranth, spinach, winter melon, winter melon seeds, large cucumber, luffa, kelp, Job's tears, mung beans, Houttuynia cordata, linden leaves, and clover sprouts.

　　2. Peritonitis patients can drink more juice and fruits that have a cooling and diuretic effect, such as pear juice, apple juice, watermelon juice, orange juice, tangerine juice, and herbal tea such as Houttuynia cordata tea.

　　3. Peritonitis patients should drink more than 2500ml of water daily.

　　4. Peritonitis patients should avoid spicy and刺激性 foods such as chili, chili sauce, onions, pepper, curry powder, etc., as they can worsen inflammation.

　　5. Patients with peritonitis should avoid eating cold and raw foods, such as frozen food.

　　I. Treatment

　　Non-surgical treatment or surgical treatment is adopted based on different etiologies, stages of the disease, and the patient's physical condition. The former is a preparatory stage for the latter. Generally, comprehensive treatment with surgery as the main method is performed, and non-surgical therapy is only allowed in a few cases. If there is deterioration, it should be quickly switched to surgical treatment.

　　1. Non-surgical treatment

　　It is mainly suitable for short-term observation of patients who have not yet been diagnosed, for patients with mild localized peritonitis with good general condition and mild disease, and for those with peritonitis that has exceeded 48 or 72 hours, is localized, and has mild toxic symptoms.

　　(1) Position: Patients without shock should adopt a semi-recumbent position. This position is beneficial for the accumulation of peritoneal effusion in the pelvis, facilitating localized absorption, even if pelvic bladder-rectal or uterus-rectal abscesses form, they are easily drained; it can prevent the accumulation of effusion under the diaphragm, which may cause toxic symptoms or lead to abscess formation; the semi-recumbent position can relax the abdominal muscles, relieve the diaphragm from compression; it can also relax the upper abdominal muscles in postoperative patients. However, during the semi-recumbent position, it is important to frequently move the legs and change the compressed areas to prevent the formation of lower limb venous thrombosis.

　　(2) NPO (Nausea and Vomiting, Obstruction, Pain) and gastrointestinal decompression: This is one of the important methods for treating peritonitis. Gastrointestinal decompression can alleviate abdominal distension in patients, prevent the continued leakage of gastrointestinal contents, and promote the recovery of gastrointestinal motility. However, prolonged decompression can increase patient discomfort and may affect electrolyte and acid-base balance or lead to certain complications. Placing a nasogastric tube for continuous decompression can prevent or alleviate intestinal dilatation, reduce or stop the overflow of digestive juices in upper gastrointestinal perforations, and play a therapeutic role.

　　(3) Correction of hypovolemia and low organ perfusion: During acute diffuse peritonitis, there may be a large amount of body fluid retained in the third space within the peritoneal cavity, surrounding tissues, viscera, and gastrointestinal tract, leading to a decrease in circulating blood volume and a sharp reduction in functional interstitial fluid. In addition, large amounts of vomiting and the inability to eat continuously can cause severe dehydration, metabolic acidosis, oliguria, and in severe cases, hypotension or shock. The fluid lost in this situation is isotonic with electrolytes and extracellular fluid. Based on this characteristic, the administration of balanced salt solution can achieve good results.

　　To determine the status of fluid replacement, it is necessary to continuously monitor the function of important organs, including blood pressure, heart rate, central venous pressure (CVP), hourly urine output and specific gravity, hematocrit, serum creatinine, and blood urea nitrogen, among others. For elderly patients or those with poor pulmonary or cardiovascular function, the changes in pulmonary artery pressure (PAP) and pulmonary artery wedge pressure (PAWP) should be monitored. When using colloidal fluids (human serum albumin), due to increased permeability of the pulmonary vasculature after systemic infection, more colloids will渗入 the interstitial space of the lungs. Large amounts of human serum albumin administration can lead to pulmonary edema. Therefore, when administering large volumes of fluids, it is important to maintain hematocrit around 35% and to enhance diuresis.

　　(4) Nutritional support: Due to the influence of the underlying disease and the inability to eat after the illness, patients with acute peritonitis are nutritionally deficient from the beginning. The diffuse peritoneal inflammation also places the body in a state of high catabolic metabolism, causing the patient to quickly experience an energy crisis. Therefore, exogenous energy substrates are needed for support, usually provided through total parenteral nutrition.

　　The energy substrate should be provided by dual energy sources, i.e., using glucose and fat emulsion injection to provide calories. If a large amount of high-concentration glucose solution is used alone to supplement energy, it may lead to more complications. Crystalline amino acid solution is used as a supplement for nitrogen source, and it is necessary to provide up to 20g/kg per day to maintain nitrogen balance and increase protein synthesis to compensate for protein catabolism. In addition, water-soluble and fat-soluble vitamins, trace elements, and electrolytes are also needed. For patients with long-term fasting, attention should be paid to the supplementation of phosphorus.

　　(5) Application of antibiotics: Peritonitis is an absolute indication for the use of antibiotics. The pathogenic bacteria of abdominal surgical infectious diseases are mostly mixed infections of aerobic bacteria and anaerobic bacteria. In the early stage of peritonitis, aerobic bacteria infection is often dominant, while in the later stage, anaerobic bacteria infection is dominant. According to drug sensitivity tests, although aerobic bacteria are very prone to develop drug resistance, at present, most of them are sensitive to third-generation cephalosporins, while anaerobic bacteria have less drug resistance and are most sensitive to metronidazole or tinidazole. Therefore, it is better to use combined medication in clinical practice. At present, China attaches great importance to the prophylactic use of antibiotics before surgery, which has reduced the incidence of abdominal infection caused by surgery.

　　It is common to have respiratory dysfunction and renal function changes in the treatment of acute diffuse peritonitis, so it should be avoided to use nephrotoxic antibiotics.

　　(6) Organ function support: such as respiratory function support, renal function protection, and the prevention of acute stress ulcer bleeding, etc.

　　2. Surgical treatment

　　Including the repair of organ perforation, the removal of intra-abdominal lesions, bacteria, and infectious matter, decompression to avoid the occurrence of abdominal compartment syndrome (abdominal compartmentsyndrome), and the prevention of persistent and recurrent peritonitis.

　　(1) Timing of surgery: The complete aspiration of purulent exudate in the peritoneal cavity is extremely important for preventing the formation of late-stage intra-abdominal abscesses. Therefore, most patients require emergency surgical treatment. For patients with unclear diagnosis of the primary lesion, or those who do not exclude the possibility of intra-abdominal visceral necrosis and perforation, or those with severe infection, laparotomy should also be performed to avoid delay in treatment. For patients with septic shock, after active preparation, it is not necessarily required for the condition to be completely stable, and emergency surgery should be performed to remove the focus of infection, clean the peritoneal cavity, and reduce the absorption of toxins. Some patients with clear diagnoses, such as acute perforation of peptic ulcer when in a fasting state, with localized peritonitis and a trend of reduced abdominal pain, may not need surgery temporarily; for acute necrotizing pancreatitis without evidence of infection, surgery may also be temporarily postponed, but peritoneal puncture and drainage can be performed to reduce the absorption of cytokines; for certain pelvic inflammatory diseases or acute diffuse peritonitis that have exceeded 48-72 hours and have a localized tendency, surgery may also be temporarily delayed, and close observation is required. In summary, whether to perform emergency surgery should be determined according to the condition.

　　(2) Surgical methods:

　　① Incision: According to the location of the primary lesion, the corresponding incision is adopted. For patients with unclear diagnosis, unless there is more obvious peritonitis on the left side, a small right rectus muscle incision is generally used. After exploration, the incision can be extended upwards or downwards as needed. The incision should be close to the lesion site, and the length should be sufficient.

　　② Exploration: After laparotomy, the exudate in the abdominal cavity should be aspirated as much as possible first. If there is omentum wrapping or cloudy fluid accumulation, it is usually the location of the primary focus. In general, no extensive exploration is performed except for suspected other foci (such as trauma), to avoid the spread of infection or exacerbation of toxin absorption.

　　③ Focal clearance: The primary focus is the source of infection in acute purulent peritonitis. Clearing the focus is the most fundamental and most important means of treating peritonitis. In principle, the focus should be treated according to the patient's tolerance. For those who cannot tolerate it, stoma or repair can be performed, and local tube drainage can be placed. Do not risk the patient's life to

　　During the operation, the operation should be gentle to minimize the injury to the intestinal tract and the traction of the mesentery. The necrotic appendix and gallbladder should be resected according to principle, but if the inflammation is severe, the anatomical level is unclear, and the patient's condition is serious, drainage or cholecystostomy can be performed, and the operation can be repeated after the condition is stabilized. For intestinal obstruction and necrotic intestinal tract with severe conditions that cannot be resected, the necrotic intestinal segment should be initially placed outside.

　　④ Abdominal cleaning: After removing the focus, the exudate, pus, food residue, feces, foreign bodies, and other substances in peritonitis should be cleaned and aspirated as much as possible. For localized peritonitis, aspirating the pus is sufficient, and there is no need for abdominal lavage to avoid the spread of infection; for diffuse peritonitis, the abdominal cavity is severely contaminated, or there are gastrointestinal contents and other foreign bodies, and if the patient's condition permits, a large amount of normal saline can be used to lavage the abdominal cavity and aspirate it. If necessary, 0.1% iodophor 1000ml can be used to lavage the abdominal cavity, but it is contraindicated for those with hyperthyroidism, renal insufficiency, or iodine allergy. During the lavage process, attention should be paid to whether the patient's respiration is suppressed. If necessary, abdominal continuous perfusion can be applied.

　　⑤ Abdominal drainage: There is still controversy about whether to place a tube for drainage after peritonitis. The author believes that for acute diffuse peritonitis where the primary focus has been completely treated, generally, it is not necessary to place an abdominal drainage. Drainage is only used for those who have formed abscesses, or there are unprocessed foci, necrotic tissue, hemorrhage, and gastrointestinal fistulas left in the abdominal cavity.

　　Among various kinds of drainage, it is recommended to use Li's tube (double套管negative pressure aspiration) drainage. Indications for abdominal drainage after surgery:

　　A, the focus cannot or should not be immediately resected from the affected organ.

　　B, there is a possibility of leakage after suture after the focus on the hollow viscera is cleared.

　　C, there is residual necrotic or vitalityless tissue in the focus.

　　D, surgery involving the pancreas.

　　E, there is tissue infection behind the peritoneum, or contamination behind the peritoneum.

　　⑥ Application of laparoscopic technology: Targeted treatment according to the location of the lesion, while open surgery cannot achieve small incision exploration to clearly identify the cause and perform therapeutic surgery. It has been reported that laparoscopic surgery can be performed for gastric and duodenal ulcer perforation plugging and repair. In cases where it is difficult to distinguish between ulcer perforation and appendicitis, laparoscopic technology can avoid the embarrassing situation of changing incisions or extending the incision upwards due to misdiagnosis in open surgery. During the conversion to open surgery, it can also guide the selection of incisions. During laparoscopic surgery, the excised purulent tissue can be removed through an aseptic bag without directly contaminating the puncture site, significantly reducing the chance of wound infection. Due to the small interference with the peritoneal cavity, the peritoneal cavity and pelvis can be thoroughly flushed under direct vision, and the incidence of postoperative intestinal adhesions and peritoneal pelvic abscesses is also correspondingly reduced.

　　However, laparoscopic exploration cannot completely replace traditional laparotomy at present: first, because laparoscopy can only see the surface of the organs and cannot palpate the deep structures; secondly, the operator of laparoscopy must have rich experience in abdominal surgery, and when the changes in the condition during surgery cannot be explained, it should be timely and resolutely transferred to laparotomy to thoroughly investigate the cause.

　　(3) Postoperative management: Whether to adopt intensive care is determined according to the APACHE-Ⅱ (Acute Physiology and Chronic Health Evaluation II Scoring System) score. After anesthesia recovery, adopt a semi-recumbent position to allow the exudate to flow into the pelvic cavity. Keep the gastrointestinal decompression unobstructed until the gastrointestinal function is restored. Pay attention to the supplementation of water and electrolytes, and provide total parenteral nutrition support as early as possible, but pay attention to starting from half the amount during the stress period and gradually transitioning to the full amount. Strengthen the use of antibiotics and make necessary adjustments according to the situation. For patients undergoing staged surgery such as colostomy, intestinal fistula, and small bowel ostomy, they generally undergo curative or definitive surgery after 3 months of surgery, depending on the situation.

　　According to the continuous prediction of 5030 severe cases, the mortality rate of patients with an APACHE-Ⅱ score of 24 is 50%; the mortality rate of patients with more than 42 points is more than 90%.

　　II. Prognosis

　　The mortality rate of severe secondary peritonitis is very high, reaching more than 20%. Most patients die early due to multiple organ failure, and a few patients die due to residual abdominal infection, especially diaphragmatic abscess or multiple abscesses, which drag on for several days and finally die of chronic consumption and exhaustion. Some patients may develop intestinal adhesion or adhesion bands due to the fibrin formation in the exudate of peritonitis, causing acute intestinal obstruction, which can also exist for a long time with chronic incomplete intestinal obstruction symptoms, which are difficult to cure.