2014年 · 第94卷第05期

Currently, according to ventilator-associated pneumonia (VAP) definition and patient population, the incidence of VAP globally is 6% to 52% or (1.6 to 52.7) cases per 1 000 mechanical ventilation days, and the case fatality rate is 14% to 50%. VAP leads to prolonged stay in intensive care medicine (ICU), increased hospitalization costs, and is an important cause of death in critically ill patients. In the past decade, the United States, the United Kingdom, Canada and other countries have successively issued VAP-related diagnosis and treatment guidelines^[1,2,3,4]Great progress has been made in the prevention and treatment of VAP, and the incidence rate has been declining. In the United States, there are even calls to include VAP in the government medical insurance agency's refusal to pay catalogue. However, the situation of high morbidity and mortality of VAP in China is still grim. How to contain VAP has become an important issue in the field of clinical medicine. Recently, the Critical Care Branch of Chinese Medical Association issued the "Guidelines for the Prevention, Diagnosis and Treatment of Ventilator-Associated Pneumonia (2013)"^[5](hereinafter referred to as the VAP Guide). It draws on the experience of major academic organizations at home and abroad, such as American Society of Critical Care Medicine, Thoracic Association, British Association of Antimicrobial and Chemotherapy, etc. in formulating guidelines. Based on common and hot clinical issues, combined with recent research progress, the method of evidence-based medicine is applied, and the prevention, diagnosis and treatment of ventilator-associated pneumonia are introduced in detail.

With the rapid development of critical care medicine in China in recent years, the clinical treatment level of critically ill patients has made remarkable progress. More and more critically ill patients have improved their prognosis after treatment in the Department of Critical Care Medicine (ICU), and most of them need to receive mechanical ventilation treatment. Mechanical ventilation plays a vital role in ensuring oxygen metabolism and treating respiratory failure caused by different causes, and can provide time for the treatment of primary disease. And the related complications caused by it have attracted more and more attention. Among them, ventilator-associated pneumonia (VAP) is one of the most common complications.

Ventilator-associated pneum-onia (VAP) is a common complication in patients with mechanical ventilation and one of the most common nosocomial infections in patients in the Department of Critical Care Medicine (ICU). Despite the rapid development of critical care medicine, the increasing popularity and improvement of mechanical ventilation technology, and the widespread use of broad-spectrum antibiotics, the incidence and mortality of VAP remain high^[1]。 Therefore, how to effectively prevent VAP has become an increasingly concerned issue for intensive care doctors. In 2013, the Critical Care Medicine Branch of the Chinese Medical Association formulated the Guidelines for the Diagnosis, Prevention and Treatment of VAP, in which how to prevent VAP became the focus of everyone's interest. In a sense, VAP is like many diseases such as tumor, coronary heart disease and diabetes. The significance of prevention is far greater than treatment. We should strive to achieve zero VAP infection in ICU through the implementation and implementation of active preventive measures. The prevention section of the VAP Guidelines is divided into four parts according to different content directions: device-related preventive measures, operation-related preventive measures, drug prevention and clustered preventive protocols.

Ventilator-associated pneum-onia (VAP) refers to pneumonia in patients with tracheal intubation or tracheotomy 48 hours after mechanical ventilation. Pneumonia within 48 hours of withdrawal and extubation also belongs to VAP. VAP is one of the most common infectious diseases in patients undergoing mechanical ventilation in intensive care unit (ICU). It can lead to prolonged hospital stay and ICU stay of patients undergoing mechanical ventilation, increase the use of antimicrobial drugs, and seriously affect the prognosis of critically ill patients. VAP is affected by many factors in clinical manifestations, imaging manifestations and pathogenic examination, so it is difficult to grasp the diagnosis. Therefore, the Critical Care Medicine Branch of Chinese Medical Association has promulgated the diagnosis, prevention and treatment guidelines of VAP after a large number of literature reviews and summarizing domestic research and experience, trying to provide the basis and reference for clinical work.

In June 2013, the Critical Care Medicine Branch of Chinese Medical Association released China's first medical guideline based on the GRADE classification method-"Guidelines for the Prevention, Diagnosis and Treatment of Ventilator-Associated Pneumonia (VAP) (2013)"^[1]。 On the basis of summarizing the existing evidence-based medical evidence and combining the discussion opinions of top domestic critical care experts, the Guidelines reached a consensus on the diagnosis, prevention and treatment of ventilator-associated pneumonia (VAP), and formulated practical and standardized recommendations suitable for the prevention and treatment of VAP in China.

Ventilator-associated pneum-onia (VAP) refers to pneumonia in patients with tracheal intubation or tracheotomy 48 h after mechanical ventilation, and is one of the most common nosocomial-acquired infections in patients within the Department of Critical Care Medicine (ICU). The reported incidence and mortality of VAP are high both at home and abroad. Once VAP occurs, it is easy to cause difficulty in withdrawing, prolong the patient's ICU stay and hospital stay, increase the related medical expenses, and lead to an increase in the patient's mortality rate, which seriously affects the patient's prognosis. Early recognition and diagnosis, effective and comprehensive prevention and active and effective treatment of VAP have become urgent problems in critical care medicine. In order to standardize the diagnosis, prevention and treatment of VAP, the Critical Care Medicine Branch of Chinese Medical Association has formulated the "Guidelines for Diagnosis, Prevention and Treatment of Ventilator-Associated Pneumonia (2013)" (hereinafter referred to as the Guidelines)^[1]In view of the outstanding problems existing in the current diagnosis and treatment of VAP, this guideline summarizes and standardizes the understanding, diagnosis, prevention and treatment of VAP from different levels, and puts forward corresponding recommendations according to the principles of evidence-based medicine. This article mainly interpreted the targeted treatment of VAP in the guidelines.

Clinical practice guidelines refer to recommendations that are systematically developed for specific clinical situations to help clinicians and patients make appropriate handling. However, how to ensure the scientific, impartial and authoritative guidelines, the methodology of developing guidelines plays a crucial role. With the development and development of evidence-based medicine, the adoption of evidence-based methods to formulate guidelines has become the mainstream trend and consensus of international clinical practice guidelines. In recent years, the number of guidelines formulated in China is increasing day by day, but the quality is not uniform, and the guidelines formulated strictly according to evidence-based methods have not been paid enough attention in China^[1]。 In view of this, we recently organized experts to apply the principles and methods of evidence-based medicine to develop guidelines for the diagnosis, prevention and treatment of ventilator-associated pneumonia (VAP) (referred to as VAP guidelines) in combination with the Critical Care Medicine Branch of Chinese Medical Association^[2]This paper introduces in detail how to formulate VAP guidelines using GRADE method, and explores the feasibility of adopting GRADE method to formulate evidence-based guidelines in China, in order to improve the quality of domestic guidelines.

A 61-year-old female developed right inguinal pain without obvious trigger one month ago, which was aggravated when walking. She came to the general surgery clinic of the Second Affiliated Hospital of Suzhou University for treatment. The abdomen was flat and soft, without tenderness and rebound pain, and there was no obvious mass in the abdomen. There was no obvious lymph node enlargement in the bilateral groin. The physiological curvature of the spine was present, and no obvious scoliosis deformity was seen. Extremities are well moved and muscle strength is normal. Mild tenderness on the right side of the pubic symphysis, longitudinal buckling pain in the right lower limb (-), pelvic crush separation test (-). Good sensory mobility in both lower limbs. The peripheral blood supply is good, and the pulsation of the dorsal pedis artery is palpable. Physiological reflexes are present, but pathological reflexes are not elicited. Pelvic MRI examination in outpatient clinic showed abnormal signal of right superior pubic branch with fracture, abnormal signal of surrounding soft tissue, abnormal signal foci of bilateral ilium and sacrum, and possible metastasis. The outpatient clinic then planned to admit "pelvic bone lesions" to the orthopedic surgery department for further diagnosis and treatment. During the course of the disease, the patient was generally in good condition, without low fever, emaciation, night sweats, normal defecation, dizziness, nausea and vomiting, shortness of breath, chest tightness, abdominal distension and diarrhea. Past physical fitness. History of hypertension, coronary heart disease and diabetes is denied. Deny the history of contact with infectious diseases such as tuberculosis, schistosomiasis and typhoid fever. History of trauma denied. Married, menopausal for 6 years. Deny the history of familial genetic diseases and infectious diseases. Vital signs normal. Blood red blood cells, white blood cells, neutrophils, liver and kidney function were normal after admission, fibrinogen was 5.120 g/L, and D-dimer was 1.81 mg/L. B-ultrasound examination showed no obvious abnormalities in liver, gallbladder, spleen and pancreas, and posterior-anterior chest X-ray examination showed no obvious active lesions in the chest. Pelvic MRI showed that the bone of the right pubic branch was discontinuous, and the broken end showed uneven length T₁WI, long T₂Wi-SPAIR signal (Figure 1), displaced bone fragments and fluid effusion were seen at the broken end (Figure 2)。 MRI diagnosis of abnormal signal of right upper pubic branch with fracture, abnormal signal of surrounding soft tissue, abnormal signal foci of bilateral ilium and sacrum, and possible metastasis; Pelvic CT scan showed that the bones of the pelvis were sparse, and bilateral sacral wings showed fracture lines running up and down (FIG. 3A), the shape of the fracture line is irregular, parallel to the sacroiliac joint, involving the 1st to 2nd sacral vertebrae on the left side, and the 1st to 3rd sacral vertebrae on the right side. Local osteosclerosis is seen, and the bone on both sides of the fracture line is slightly misaligned. S1~2 intervertebral space is irregular and pneumatic, and local bone sclerosis is seen (FIG. 3B)。 Right pubic ramus bone fracture (Figure 3C), the fracture line is perpendicular to the pubic bone, slightly displaced inward, free bone fragments are seen locally, and the soft tissue around the pubic symphysis and the right external obturator muscle are swollen. CT diagnosis of bilateral sacral wing, right pubic branch failure fracture, local callus formation, right external obturator muscle and pubic symphysis surrounding soft tissue swelling. Pathology: Partial tissue biopsy of the pathological fracture end of the right superior pubic branch showed mature trabecular bone and a small amount of cartilage tissue (Figure 4)。 The patient's condition did not deteriorate after 9 months of follow-up.

With the aging of China's population, the incidence of common diseases in the elderly, such as hypertension and cognitive dysfunction, has gradually increased. The number of patients with senile dementia, the terminal stage of cognitive dysfunction, has surged from 3.68 million in 1990 to 9.19 million in 2010^[1]It has become the third major disease that threatens the lives of the elderly after cardiovascular diseases and malignant tumors, bringing a heavy burden to social public health and economy. It has been studied that abnormal circadian rhythm of blood pressure in elderly hypertensive patients is associated with cognitive impairment^[2,3,4]And a large number of prospective studies suggest that antihypertensive therapy adjusting blood pressure rhythm is beneficial to delay the progression of cognitive impairment^[5,6]Therefore, the abnormal circadian rhythm of blood pressure in elderly hypertensive patients may be an important influencing factor of cognitive impairment, but the mechanism is still unclear and needs further research.

The earliest research on developmental brain neurotoxicity caused by general anesthetics can be traced to 1974. Quimby et al.^[1]It was reported that persistent abnormal cerebral cortical synapse formation and decline of learning and social ability in adulthood after long-term exposure to 0.01% halothane in juvenile rats. However, this study has not attracted academic attention. In 2003, Jevtovic-Todorovic et al. investigated the effects of common general anesthetics on the developmental brain. In this experiment, a "cocktail" anesthesia regimen of midazolam, isoflurane and nitrous oxide was used to anesthetize neonatal rats 7 days after delivery for 6 h. After 24 h, the neonatal rats' brains showed extensive apoptosis, hippocampal synaptic function was impaired, and the learning and memory ability of rats in adulthood was significantly reduced^[2]。 Since the results of this study were reported, the developmental brain neurotoxicity caused by general anesthetics has been widely concerned by the anesthesiology community and even the society. This review will summarize the research on developmental brain neurotoxicity caused by general anesthetics in recent years, elaborate the basic research on the effects of general anesthetics on neuronal genesis and synapse formation during neuronal development and the damage of mature neurons after division, and point out the related clinical research progress in recent years.

A 45-year-old male suffered from sudden headache and vomiting for 1 week. Nothing special in the past. Physical examination: clear, poor spirit, movable limbs. CT scan of the skull showed irregular high-density shadows in the left parietal occipital, edema of the surrounding brain tissue, obvious enhancement, compression of the ipsilateral ventricle, and right shift of the midline; MRI showed a 4 cm ×4 cm ×3 cm mass-like mixed signal shadow in the left parieto-occipital, T₁WI high signal, T₂WI is low signal, the boundary of the tumor is clear, and large patchy edema and irregular enhancement can be seen around it (Figure 1)； Preoperative diagnosis: left parieto-occipital glioma with hemorrhage. A 2 cm ×2 cm ×1 cm mass was seen on the left parietal, uniformly enhanced, closely related to the dura mater, and the preoperative diagnosis was meningioma. No pigmented spots were seen on the skin before surgery. The left parieto-occipital craniotomy was performed, and the parieto-occipital lobe was incised to see brown liquid flowing out, about 20 ml, and there was an abnormal blood vessel mass at the top of the cyst cavity; A brown mass was seen on the top of the left side, with medium texture, clear boundary and abundant blood supply. The base of the mass was close to the falx cerebri, and the tumor was totally removed under the microscope. Pathological diagnosis: metastatic malignant melanoma (epithelial cell type), immunohistochemistry: S-100 fraction (+), HMB45 fraction (+), Vim fraction (+), NSE (-), SY (-), CK (-), LCA (-), CD20 (-), CD79a (-), CD45RO (-), CD3 (-). After discharge, he was treated with gamma knife and died 8 months after surgery.