End-stage pneumonia in the elderly

　　终末期肺炎患者以老年为多。随着年龄的增大，其呼吸系统结构、功能及呼吸力学的退行性变，上呼吸道的加湿功能减退，排痰能力减退，特别是脑血管病、意识障碍的患者，吞咽反射及咳嗽反射的刺激阈均明显升高，喉头功能障碍，睡眠中易出现误吸造成吸入性肺炎。鼻饲患者由胃管刺激引起呕吐也可导致吸入性肺炎。故在终末期肺炎中，吸入性肺炎占有相当多的比例。也有一部分是由于机体免疫力低下，细菌从身体其他部分通过血行进入肺内，造成肺部感染，包括真菌。

　　人每天吸入的空气在1万升以上，其中可能含有大量微生物，一般情况下肺和呼吸道的防御机制可将这些致病因子排出、灭活和消除，但如吸入的病原微生物过多或过强或肺的防御功能减退就可能导致呼吸道炎症的发生。老年的肺与肺气肿颇相似，胸廓硬度增加，呼吸肌力量减弱，故咳嗽效果减少，加之支气管纤毛活动减退和无效腔增大，易发生呼吸道感染。终末期肺炎大多为小叶性支气管性肺炎，即感染可沿支气管分布，由于此类患者吞噬细胞功能的减退，不能及时吞噬肺泡内的异物(死亡的细菌等)，易导致吸收延缓性肺炎，即应用敏感抗生素后，症状体征消失，但胸部X线检查炎症阴影长期不吸收。吸入性肺炎时吸入物可刺激气管引起支气管痉挛，之后造成支气管上皮的急性炎症及支气管周围炎症浸润，进入肺泡的胃液迅速扩散至周围组织，肺泡上皮细胞破坏、变性，并累及毛细血管壁，血管通透性增加，形成间质性肺水肿。吸入食物或异物时若将口腔寄居菌带进肺内，形成肺脓肿。肺水肿使肺组织弹性减弱，顺应性降低，肺容量减少，加之肺泡表面活性物质的减少，使小气道闭合，肺泡萎陷引起微肺不张，均可造成通气不足，通气血流比例失调和动静脉分流增加，导致低氧血症或酸中毒。

　　Complications of elderly terminal pneumonia include respiratory failure, arrhythmia, renal heart failure, electrolyte disorder, etc. In severe cases, it affects gas exchange, causing a decrease in arterial blood oxygen saturation and cyanosis. A few patients may have gastrointestinal symptoms such as nausea, vomiting, abdominal distension, or diarrhea. Severe infections can cause confusion, irritability, drowsiness, and coma. There may be an increase in respiratory rate, flaring of the nostrils, and cyanosis. In the case of lung consolidation, there are typical signs such as dullness on percussion, increased vocal vibrations, and bronchial breathing sounds, and wet rales may also be heard.

　　Elderly terminal pneumonia generally has an insidious onset, most of which do not have typical pneumonia symptoms such as fever, cough, and sputum, and the onset usually manifests as malaise, fatigue, bedridden, incontinence of urine and feces, changes in consciousness, and frequent falls, which are prone to misdiagnosis and missed diagnosis, and the course of the disease is easy to prolong; the changes in the condition are diverse, and complications are common, such as respiratory failure, renal heart failure, arrhythmia, electrolyte disorder, dehydration, etc., with poor prognosis; there are often multiple organ dysfunction or malnutrition, systemic failure; there are characteristics of recurrent infection; the efficacy is poor, and the mortality rate is high.

　　With the aging of the population, the structure and function of the respiratory system undergo a series of changes, including reduced cough reflex, kyphosis, and other changes, making the elderly prone to pneumonia and death. Changes in the defense function of the elderly body include increased mucus secretion of the lung tissue, weakened ciliary movement, reduced phagocytic activity of polymorphonuclear leukocytes, and a significant lack of T cell function associated with aging, all of which create opportunities for microbial invasion. Elderly patients with various chronic diseases are prone to pneumonia at the end stage, from the perspective of prevention, the community should register and file these terminal patients with the above diseases, regularly carry out health education for the patients and their families, and targeted vaccination can be carried out according to seasonal changes and the prevalence of pathogens. It is best to avoid contact with patients with respiratory tract infections, frequently open windows for ventilation, regularly boil vinegar to disinfect the room air, and for patients who have been lying in bed for a long time, they should be turned over and the back should be patted regularly to facilitate the drainage of respiratory secretions and reduce the chance of infection. Daily oral hygiene care should be performed to prevent the inhalation of pathogenic microorganisms. Ensure sufficient sleep time, and the diet should provide nutritious food. Functional exercises can be done in bed to enhance the body's immunity. If the patient has symptoms such as fever, malaise, refusal to eat, changes in consciousness, etc., they should be sent to the hospital for immediate treatment.

　　Symptoms of terminal pneumonia in the elderly are atypical, and diagnosis is mainly made through the following clinical examinations.

　　1. Electrocardiogram

　　In this disease, 60% to 70% of cases show abnormalities in the electrocardiogram, including inverted T waves, depressed ST segments, premature contractions, atrial fibrillation, and pulmonary P waves.

　　2. Imaging

　　Terminal pneumonia, due to不明显 symptoms and signs, the diagnosis mainly relies on X-ray, which often shows small patchy shadows along the bronchus, with the lower lobe on the right being more prominent. However, in clinical practice, it is also possible to hear obvious vesicular sounds in the lungs, while the chest X-ray shows no obvious inflammatory signs, which may be related to long-term bed rest, inflammatory secretions accumulating around the spine, leading to unclear inflammatory shadows. In addition, if heart failure is present, the heart shadow may enlarge, and signs of pleural effusion may be seen. The cause is considered to be due to a combination of pleurisy, hypoproteinemia, and heart failure.

　　3. Blood tests

　　Leukocytosis is less common than general pneumonia, with 40% to 50% of cases showing normal white blood cell counts, 90% showing nuclear left shift, 50% showing varying degrees of anemia, and about 80% of patients showing an increased erythrocyte sedimentation rate. It often accompanies hypoproteinemia, with plasma protein and total protein levels below normal, as well as hypokalemia and hyponatremia. Hypochloremia is common. In 50% of cases, blood gas analysis shows hypoxemia, with carbon dioxide partial pressure usually at normal levels. When complicated with chronic obstructive pulmonary disease, hypercapnia may occur. Sputum bacteriology examination: In terminal pneumonia patients, due to weakened expectoration ability or due to impaired consciousness, satisfactory sputum specimens cannot be obtained, making etiological diagnosis difficult. However, reliable etiological diagnosis is urgently needed for patients with severe or ineffective empirical treatment. The most useful technique at present is bronchoscope-assisted sputum collection to prevent contamination, but it does carry certain risks. Generally speaking, if the oxygen partial pressure is greater than 8 kPa (60 mmHg), without severe cardiovascular disease, without abnormalities in coagulation mechanism, and after adequate preparation, this technique is applicable. The common pathogenic bacteria in terminal pneumonia include Streptococcus pneumoniae, Haemophilus influenzae, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Listeria, and other Gram-negative bacilli. Other pathogens include fungi, viruses (including cytomegalovirus, herpes zoster virus, etc.), and parasites (including Pneumocystis carinii, Strongyloides stercoralis) and so on.

　　The diet of pneumonia patients should be based on the patient's recovery, the supplement of nutrients, and the enhancement of the body's ability to resist diseases, and should consume high-calorie, high-vitamin, high-protein, and easily digestible food. Fever patients should drink plenty of water and eat more fruits, and avoid eating high-fat food. For patients with consciousness disorders, long-term bed rest, exhaustion, and weakened cough reflex, regular turning and patting the back, nebulization therapy, and, if necessary, sputum aspiration should be performed to facilitate sputum drainage. For patients with hypoxemia, oxygen should be administered to improve the functional state of the organs. If there is difficulty in eating, nasogastric feeding or intravenous hyperalimentation can be given to improve the nutritional state of the body..

　　Considering the characteristics of patients with end-stage elderly pneumonia, mainly antibacterial treatment is carried out, and the basic principles of treatment are as follows:
　　1. Inquire about the medical history in detail, carefully examine the body, understand the underlying diseases, past medication history, and clarify the severity of the infection.
　　2. Try to obtain accurate etiological evidence.
　　3. Start empirical antibacterial treatment as soon as possible.
　　4. Adjust medication according to the etiology at any time.
　　5. Pay attention to the adverse reactions of drugs.
　　6. Avoid using drugs that are harmful to the liver and kidney function.
　　7. Optimal Program: ① 60ml of 0.9% saline + 0.5g imipenem-cilastatin sodium (Tienam), 1 time/8h, intravenous infusion. Or 100ml of 0.9% saline + 2.0g cefoperazone/sulbactam (Sulperazon), 2 times/d, intravenous infusion. Or 100ml of 0.9% saline + 4.5g talazopar, 2 times/d, intravenous infusion. ② If fungal infection is involved, fluconazole (Diflucan) 0.2-0.4g, 1 time/d, oral.
　　The incidence of end-stage elderly pneumonia is higher than that of young and middle-aged pneumonia. With the increase of age, the incidence and mortality rate increase significantly, and the mortality rate of end-stage elderly pneumonia is 3 times that of young and middle-aged pneumonia.