Nosocomial pneumonia in the elderly

　　Chinese and foreign monitoring studies have found that the risk factors for elderly hospital-acquired pulmonary infections include: tracheal intubation and/or mechanical ventilation, thoracoabdominal surgery, unconsciousness, coma (especially in patients with closed craniocerebral injury), massive aspiration, chronic pulmonary disease, and elderly individuals (age over 50 years). Other risk factors include: not changing the ventilator pipeline in time, in autumn and winter, prophylactic medication for stress ulcer bleeding (ranitidine, antacids), using antibiotics when an NG tube is in place, severe trauma, and recent fiberoptic bronchoscopy. Foreign research has found that the incidence of hospital-acquired pneumonia after thoracoabdominal surgery is 38 times higher than that after surgery in other parts. Foreign research reports that the use of mechanical ventilation is one of the important causes of hospital-acquired pulmonary infection.

　　Elderly hospital-acquired pneumonia has many complications, such as respiratory failure, heart failure, pulmonary edema, arrhythmia, respiratory acidosis, pulmonary encephalopathy, massive gastrointestinal bleeding, electrolyte and water disorders, shock, acute myocardial infarction, and so on. Chest wall and pleurisy are the second most common complications.

　　The specific clinical symptoms of elderly hospital-acquired pneumonia are as follows:

　　Section 1: Viral Pneumonia

　　Generally occurs in winter and spring, mostly from November to March or April of the following year, slightly later than the outbreak of community-acquired viral infections. The main source of infection is patients admitted with viral respiratory tract infection. Early patients may experience fatigue, general malaise, and decreased appetite. Fever is usually absent. Local symptoms are mostly catarrhal symptoms of the nasopharynx, such as nasal congestion, runny nose, and sneezing after mucosal congestion and edema. With the progression of the disease, it can invade the pulmonary parenchyma and interstitium, manifesting as cough, mostly paroxysmal dry cough, dyspnea, chest pain, fever. In addition to the general symptoms of pneumonia, some patients may have persistent high fever, severe cough, hemoptysis, palpitations, shortness of breath, cyanosis, and can develop heart failure and acute renal failure, even shock. During the early physical examination, the lungs may be normal, or there may be mild signs such as mild dullness on percussion, weakened breath sounds on auscultation, and scattered dry and moist rales. When the condition worsens, widespread moist rales and wheezing sounds can be heard on pulmonary auscultation, and rarely are there signs of consolidation.

　　Section 2: Bacterial Pulmonary Infection

　　Hospital-acquired pulmonary infections are often caused by Gram-negative bacilli. Due to the non-specificity of symptoms and the diversity of pathogens, the onset is often insidious. In the early stage, patients may present with symptoms such as apathy, drowsiness, fatigue, shortness of breath, and chest tightness. The body temperature is usually normal or slightly elevated, the pulse is relatively slow, and about half of the patients may present with respiratory symptoms such as cough and expectoration. The sputum is usually yellow sputum. When infected with Pseudomonas aeruginosa, patients may cough up green or yellow sputum. Klebsiella pneumoniae sputum is thick, and some may be brick-red gelatinous in appearance. A few patients may experience hemoptysis; Escherichia coli infection results in a large amount of sputum with an odor, mostly white or yellow mucus; Serratia infection can lead to a 'false hemoptysis' phenomenon caused by certain strains producing red pigments. If the condition worsens further, the patient's condition can deteriorate rapidly, with some patients developing pulmonary empyema, pleurisy, sepsis, and septic shock, which can lead to high fever, thick sputum that is difficult to cough up, confusion, anemia, systemic failure, respiratory distress, and blood pressure drop, and ultimately die from respiratory and circulatory failure, with a mortality rate of up to 60%. On auscultation, scattered medium and small vesicular sounds may be heard in the lungs, often at the base, and dry rales may also be heard. In the late stage of the lesion, rales can be more widespread, often with a sputum rale as the main sound. About 20% of patients may not hear pulmonary rales, and it is generally difficult to see signs of lung consolidation. Hospital-acquired legionnaires' pneumonia often occurs in outbreaks, and patients may have symptoms such as malaise, myalgia, chest pain, dry cough, and low fever, resembling influenza symptoms. A few patients may have a small amount of mucous sputum or sputum with a small amount of blood. The condition can deteriorate rapidly 1-2 days after onset, with symptoms such as high fever, confusion, abdominal pain, diarrhea, vomiting, and respiratory distress. Lung rales may be heard, and some patients may involve the pleura. According to statistics, legionnaires' pneumonia accounts for about 14% of hospital-acquired pulmonary infections and has a mortality rate of 3.8% to 6.6%. In patients who are long-term bedridden, after thoracoabdominal surgical operations, tracheal intubation, etc., due to a large amount of sputum, complex and intricate mucous secretions in the airway, dysfunction of the cilium transport system, weakened cough reflex, and other conditions, it is often easy to have poor sputum drainage, leading to sudden unilateral lung collapse, which manifests as persistent respiratory distress, increased respiratory rate, tracheal depression, and hypoxemia. Physical examination may reveal mediastinal shift to the affected side and the disappearance of respiratory sounds on the affected side of the lung.

　　3. Fungal Pneumonia

　　It often occurs as a secondary infection after bacterial pneumonia, viral pneumonia, tuberculosis and other diseases. Patients often have a history of long-term use of broad-spectrum antibiotics and large amounts of hormone and immunosuppressant use. Common fungi include Candida albicans, Aspergillus, followed by Mucor, Cryptococcus neoformans, Nocardia, and actinomycetes. Occasionally, Histoplasma can be seen. Fungal lung infections mainly manifest as allergic symptoms and inflammation. Symptoms are non-specific and often masked by the primary disease. Hospitalized susceptible individuals, once the body temperature, sputum volume, sputum characteristics, and the primary pulmonary disease do not improve after long-term treatment, and new inflammatory lesions appear on the chest X-ray, should consider the possibility of pulmonary fungal infection.

　　The prevention of hospital-acquired pneumonia in the elderly can be divided into three levels, specifically as follows:

　　Primary Prevention

　　Also known as etiologic prevention. At this stage, the disease has not occurred, but the risk factors already exist, such as severe primary diseases like liver, brain, and kidney organ failure, weakened body resistance, advanced age, and emotional stimulation leading to low mood. Surrounding infectious sources such as respiratory, digestive, and urinary system infections. This level of prevention can be divided into promoting health and special protection.

　　Second-level prevention

　　The prevention at this stage mainly includes early detection and timely treatment.

　　1. Early detection:Elderly inpatients are a high-risk group for hospital-acquired pneumonia. They should be carefully observed and regularly examined. If symptoms such as fatigue, malaise, anorexia, or a slight cough appear on the basis of the original illness, physical examination and laboratory tests should be performed to detect pulmonary infection early.

　　2. Timely treatment:Once hospital-acquired pneumonia is discovered, it should be treated promptly, and effective antibiotics should be administered according to the different pathogens. Antiviral or antibiotic and antifungal drugs should be used for treatment. Timely control of the condition, prevention of disease changes, and avoidance of complications should be carried out.

　　Three-level prevention

　　Also known as clinical prevention, it mainly relies on various clinical methods to promote the early recovery of pneumonia and reduce the adverse consequences caused by the disease. Hospital-acquired pneumonia in the elderly may be complicated by some complications, and it is extremely important to actively treat these complications.

　　The clinical examination of hospital-acquired pneumonia in the elderly is as follows:

　　1. Laboratory examination of pathogens

　　1. Sputum pathogen examination:It is of great significance in the diagnosis of hospital-acquired pneumonia in the elderly, but it is easily contaminated by oropharyngeal microorganisms through routine sputum culture, and its reliability is relatively low. However, at present, most hospitals in China, especially primary-level hospitals, due to limited conditions, this method is the main method for collecting specimens. Therefore, before collecting sputum specimens, gargle with physiological saline or hydrogen peroxide thoroughly, and pay attention to cough deeply as much as possible. This can significantly reduce oral pathogenic bacterial contamination and improve the reliability of detection. Bronchoscopy is more convenient for patients who already have tracheal intubation, as fiberoptic bronchoscopy must pass through the oropharynx or tracheal intubation site where the bacterial translocation rate reaches 90%, so the aspirated material is easily contaminated. To avoid contamination, two techniques can be used, one of which is the protective brush, which requires effective collection of uncontaminated lower respiratory tract specimens under the guidance of X-ray film positioning, with a sensitivity of 75%. The other method is protective alveolar lavage, collecting lavage fluid for bacteriological examination, with a sensitivity of up to 86%. After collecting specimens with sterile containers, they must be sent for testing immediately. The first step is to perform microscopy, observe the morphology, type, and quantity of cells, whether there is damage to the columnar epithelium and its cilia, the type, distribution, and quantity of bacteria between or within cells, the presence or absence of capsules and flagella, and the presence or absence of hyphae and spores. If the specimen is indeed taken from the lower respiratory tract, microscopy still has great significance for quickly determining the approximate classification of bacteria, obtaining preliminary diagnosis, and guiding clinical treatment. In addition, sputum specimens should be cultured as soon as possible, and after culture, identification should be made based on the characteristics of bacterial colonies, the color produced, biochemical tests, and motility tests, etc.

　　2. Blood culture:It plays an important role in hospital-acquired pneumonia, and a considerable number of patients have bacteremia. Therefore, it is recommended to collect blood samples for culture before using antibiotics or in the early stage of chills and fever in patients, which can improve the positive rate.

　　3. Serological testing:It is mainly used for viral diagnosis. Different viruses can be diagnosed by different methods. Influenza virus can be diagnosed by hemagglutination inhibition test, complement fixation test, and ELISA method. When cytomegalovirus infection occurs, respiratory tract secretions or tissue specimens can be collected and inoculated into human embryonic fibroblast culture medium to isolate cytomegalovirus. It can also be diagnosed by checking for cytomegalovirus. Measles virus can detect specific IgM antibodies in serum by ELISA method for early diagnosis. Serum complement fixation test is also helpful for diagnosis when the titer of double serum samples increases by more than 4 times. Respiratory syncytial virus can be detected with a positive rate of 85% to 90% by ELISA method, and can also be detected by monoclonal bridge enzyme-labeled method.

　　2. General examination

　　The total white blood cell count of some patients increases beyond 10×109/L with an increase in neutrophils, but the total white blood cell count of most elderly patients does not increase, and the neutrophil count is normal or decreased. The changes are not specific, and the erythrocyte sedimentation rate is mostly accelerated.

　　3. Chest X-ray

　　It is extremely important for the diagnosis of hospital-acquired pneumonia in the elderly. Chest X-rays show that the lesions often occur in the middle and lower fields of both lungs, with bronchial and surrounding interstitial inflammation, manifested as increased, thickened, and blurred lung markings, lobular exudation and consolidation, manifested as blurred patchy shadows along the lung markings, uneven density, and dense lesions can merge into larger patches, and can also affect multiple lung lobes. However, in the early stage of the disease, especially when patients are dehydrated or have leukopenia, chest X-rays may be normal. Generally, after correcting dehydration for 24 hours, new infiltrative lesions can be seen on chest X-rays.

　　4. Pulmonary CT

　　CT examination plays an important role in the diagnosis of hospital-acquired pulmonary infections, especially in patients with bone marrow, organ transplantation, and the elderly. CT can often detect lesions early. The CT images of bacterial pulmonary infections mainly show multifocal inflammatory lesions in the lower lung base segments, with lesions mostly showing patchy, nodular, mass-like, and irregular shapes. Some lesions can merge together, with small cavities or honeycomb-like changes, and bronchiectasis can also be seen. When fungal pneumonia occurs, the CT images mainly show solitary or multiple fluffy inflammatory masses, nodules, and halo signs, with low-density areas around them, CT values lower than those of the lesion center, but higher than normal lung CT values.

　　Patients with hospital-acquired pneumonia in the elderly should pay attention to taking light and easy-to-digest foods in their diet, and it is recommended to eat more fresh vegetables and fruits appropriately. Especially, it is suggested to eat more foods such as white nuts, lily bulbs, white radishes, and lotus root slices. At the same time, it is necessary to avoid eating cold, spicy, and刺激性 foods, avoid smoking, drinking alcohol, drinking strong tea, staying up late, and pay attention to rest more, and avoid too much emotional fluctuations.

　　Antibiotic treatment for hospital-acquired pneumonia in the elderly must be initiated as soon as possible, taking comprehensive measures, strengthening nursing, preventing complications, improving the ability to resist diseases, and striving for early recovery. The duration of treatment should be individualized. Its length depends on the pathogen of the infection, severity, underlying diseases, and clinical therapeutic response. Recommended duration: Haemophilus influenzae 10-14 days, Enterobacteriaceae, Acinetobacter 14-21 days, Pseudomonas aeruginosa 21-28 days, Methicillin-resistant Staphylococcus aureus (MRSA) 21-28 days, which can be appropriately extended. Pneumocystis carinii 14-21 days, Legionella, Mycoplasma, and Chlamydia 14-21 days. Specific as follows:

　　First, General Treatment

　　Throughout the patient's process, careful nursing should be provided, encouraging the patient to drink more water, consume a balanced and easily digestible semi-liquid diet. For those who cannot eat, intravenous nutrition and fluid supplementation should be administered. Encourage patients to cough and expectorate phlegm, provide room humidification, and administer expectorants. Regularly perform percussion to keep the respiratory tract unobstructed, unless severe dry cough occurs, in which case sedatives and cough suppressants should be used sparingly. In case of changes in the condition, sputum aspiration should be performed as necessary, and psychological care should be provided to comfort the patient. During the acute phase, patients should rest more in bed, and after the acute phase, they should increase their activities as the condition improves. For patients with high fever and weakness, physical cooling should be provided, and drug cooling may be necessary if required, to reduce body temperature to below 39℃.

　　Second, Antibiotic Treatment

　　Research shows that the incidence of hospital-acquired pneumonia in Chinese elderly hospitals is increasing year by year. Moreover, the number of drug-resistant pathogenic strains is increasing year by year. This is related to the acceleration of China's aging process and the irrational use of antibiotics. The principle of rational use of antibiotics, the absorption, distribution, metabolism, and excretion rate of drugs in the elderly change greatly, and with age, the renal function gradually declines, aging, smoking, drug intake, diet, and underlying diseases have a significant impact on elderly drug metabolism. Due to the decrease in visceral blood flow in the elderly, the clearance of drugs with high visceral clearance rates decreases. These factors should be considered before the use of antibiotics.