Clinical diagnosis and treatment of novel coronavirus pneumonia As time goes by, doctors have a deeper understanding of the diagnosis and treatment of novel coronavirus pneumonia (COVID-19). Many doctors and scholars have put forward many good suggestions, including the use of hormones, the timing of tracheal intubation and other clinical hot issues, but many aspects lack summary. Especially for the treatment of critically ill patients, there are great differences between doctors specializing in critical care and doctors specializing in respiratory medicine. These issues urgently need clinical research to draw conclusions to guide clinical practice. We have some experience in the clinical diagnosis and treatment of COVID-19, and hope to help the front-line clinical treatment. Since our medical team is located in a Class II Grade A hospital, whether these clinical experiences are suitable for other Class III hospitals or medical centers needs to be considered. 1. Attach importance to clinical diagnostic thinking Clinicians must attach importance to clinical diagnosis. While paying attention to COVID-19, they must pay attention to differential diagnosis and diagnosis of patients' underlying diseases. In the early stage of the large-scale outbreak of the epidemic, everyone attached great importance to virus nucleic acid testing. Later, because the speed of nucleic acid testing and false negative problems affected epidemic prevention and control and clinical diagnosis and treatment, some clinicians attached great importance to chest CT imaging diagnosis, and extreme cases even proposed that nucleic acid testing was no longer needed. The author believes that clinicians must pay attention to medical history and clinical signs during the diagnosis of the disease, and conduct a comprehensive analysis in combination with laboratory tests and imaging changes. A patient admitted to West China Hospital of Sichuan University during the epidemic period had CT images that could not rule out the possibility of novel coronavirus infection, but after careful medical history and timely laboratory tests, he was finally diagnosed with Pneumocystis carinii pneumonia. In areas with high incidence of the epidemic, attention should be paid to COVID-19. Clinicians often only pay attention to the pneumonia of patients (especially non-respiratory clinicians), but they should not lose the basic skills of clinicians, especially asking patients for a complete clinical history and symptoms, such as cough, sputum volume and color, whether fever is accompanied by chills, etc., assessing patients' dyspnea every day, and paying attention to patients' underlying diseases and smoking. In a patient we treated, the patient's dyspnea and other symptoms were not serious when he was admitted to the hospital, and the CT imaging changes were not serious; but during the ward rounds, a careful inquiry into the medical history revealed that the patient had a history of heavy smoking, clinical symptoms of chronic obstructive pulmonary disease, and was overweight, so we believed that the patient was at risk of developing a critical illness and asked the resident physician to closely observe the patient's dyspnea. Although the patient was treated with lopinavir, ritonavir, arbidol and treatment for chronic obstructive pulmonary disease after admission, symptoms such as cough were quickly relieved, but the symptoms worsened again 4 days later, and the reexamination of CT showed that the lung lesions had progressed significantly. After that, respiratory support was strengthened in time and hormone treatment was given, and the patient's condition stabilized. 2. Clinical treatment strategy Our strategy is to stratify according to laboratory test results, condition and risk, and adopt corresponding treatment strategies, but be alert to the risk of developing severe and critical illness in the elderly (over 65 years old) and patients with underlying diseases such as chronic obstructive pulmonary disease and diabetes. 2.1. Patients with mild symptoms and no risk factors for progression to severe illness According to the treatment plan of the National Health Commission, these patients mainly use antiviral treatment as appropriate and give symptomatic treatment, including drug cooling when high fever, maintaining electrolyte balance, appropriate fluid and energy supplementation for those who eat and drink less, and psychological counseling for anxious patients. 2.2. Patients with mild symptoms and risk factors for progression to severe/critical illness These patients have mild symptoms at onset, but have the following risk factors: old age, chronic obstructive pulmonary disease, diabetes, cardiovascular and cerebrovascular diseases, etc. For these patients, it is necessary to evaluate the symptoms of dyspnea every day. For patients with stable dyspnea symptoms, they should be treated as mild cases and the underlying diseases should be treated according to the guidelines, but the use of angiotensin II receptor antagonists and angiotensin converting enzyme inhibitors should be avoided. Pay attention to the adverse reactions of antiviral drugs and make adjustments in time. Chest CT can be reviewed every 5 days or even longer. For patients with significantly worsening dyspnea, chest CT should be reviewed in time to understand the changes in lung imaging. For patients with rapid progression of chest imaging within 3 to 4 days (the range increases by more than 1/3 to 1/2 of the original) and obvious worsening of dyspnea, or patients whose condition progresses while using hormones in the National Health Commission's program, consider high-dose hormone shock on the basis of non-invasive mechanical ventilation (according to the patient's condition, the dose of methylprednisolone is 80 to 250 mg/time, 2 times/day, generally halved after 2 to 3 days, and then reduced again after 2 to 3 days; if the condition is stable, stop using hormones as soon as possible. During this process, closely monitor the side effects of hormones and deal with or stop using them in time. If the patient's condition worsens or the patient's condition does not improve after 3 days, mechanical ventilation or other treatment measures should be carried out in time. 2.3, Severely ill patients The most important thing is to prevent patients Progress to critical illness. For these patients, in addition to treatment according to the National Health Commission's plan, disease monitoring is very important. Blood routine, inflammatory indicators, blood gas analysis, imaging and other examinations should be carried out in a timely manner according to the patient's dyspnea and other conditions to comprehensively evaluate the patient's condition. If the patient's imaging manifestations progress, the inflammatory indicators are significantly elevated, and factors such as bacterial infection, fungal infection, and heart failure are excluded, high-dose hormone therapy can be considered. 2.4, Critically ill patients Maintaining organ function is crucial. It is recommended to adopt a multidisciplinary model of breathing + critical care + respiratory therapy + nutrition for treatment. In the epidemic area during a major outbreak, refined patient management is helpful to improve the success rate of patient treatment. Prone ventilation, lateral position, etc. have an improving effect on oxygenation in some patients. It can be used Use bedside color Doppler ultrasound, electronic stethoscope, etc. to assess the patient's lung and cardiovascular system. At this time, if conditions permit, hormone shock can still be considered. 2.5. Pay attention to the prevention and treatment of complications Pay attention to the prevention of deep vein thrombosis when patients with severe and critical illness are in bed; pay attention to the protection of important organs such as the heart and kidneys of critically ill patients; pay attention to asking patients about the amount and color of sputum to assist in judging secondary infection; pay attention to observe whether there is gastrointestinal bleeding. 2.6. Respiratory therapists and rehabilitation treatment After the outbreak of this epidemic, designated hospitals admitted a large number of severe and critical COVID-19 patients, and some patients needed respiratory support due to respiratory failure. However, due to the active participation of a large number of non-respiratory and critical medicine medical staff in designated hospitals in disease treatment, they We are not familiar with respiratory support technologies such as high flow, non-invasive ventilators and invasive ventilators. If respiratory therapists participate in these respiratory supports, the effect of respiratory support will be improved. In addition, if the patient's condition allows, rehabilitation treatment should be started as soon as possible, including moving limbs in bed, sitting and standing by the bed, and walking. During this process, it is necessary to pay attention to closely observe the patient's dyspnea and oxygenation, proceed step by step, and prevent falls. 3. Summary The diagnosis of COVID-19 should pay attention to viral nucleic acid detection, but it cannot rely entirely on viral nucleic acid detection. The application of medical history, imaging data and clinical thinking is particularly important for the diagnosis and treatment of the disease. The disease needs stratified and individualized treatment. Some severe patients need to strengthen respiratory support and nutritional support, and some patients with rapid progression can be given hormone treatment.