Aspiration pneumonia

Description:

Now it is considered authentically established that microaspiration of the bacteria colonizing a nasopharynx is the initiating factor of the majority of bacterial pneumonia. However traditionally understand the pulmonary defeats arising owing to macroaspiration of bigger or smaller quantity of contents of a nasopharynx or a stomach and the infectious process following it as the term "aspiration pneumonia".

Symptoms of Aspiration pneumonia:

Unlike the pneumonia caused by typical extra hospital strains (pneumococcus), AP develops gradually, without the accurate acute beginning. At many patients in 8-14 days after aspiration abscesses of lungs or an empyema develop. Approximately at a half of patients at emergence of the centers of destruction expectoration with a fetid putrefactive smell is noted, development of a pneumorrhagia is possible. However lack of a putrefactive smell when forming abscess does not exclude participation of anaerobe bacterias in genesis of AP (some of them, for example mikroaerofilny streptococci, do not lead to formation of the products of metabolism possessing a putrefactive smell). Other symptoms of AP do not differ from the general displays of pneumonia: cough, dispny, pleural pains, fever, leukocytosis. Many patients have several days, and sometimes and weeks such low-expressed clinical symptoms as weakness, subfebrile fever, cough, at a number of patients – progressive decrease in body weight and anemia, precede emergence of the clinical signs stated above. Feature of AP caused by anaerobe bacterias absence at a sick fever is considered.
Characteristic clinical features of AP:
• gradual beginning;
• the documentary aspiration or factors contributing to its development;
• lack of oznob;
• fetid smell of a phlegm and pleural liquid;
• localization of pneumonia in dependent segments;
• necrotizing pneumonia, abscess, pleura empyema;
• availability of gas over exudate in a pleural cavity;
• lack of growth of microorganisms in aerobic conditions.

Independent predictors of the bad forecast at AP are late diagnosis, inefficient initial antibacterial therapy (ABT), bacteremia, hospital superinfection.

Reasons of Aspiration pneumonia:

As a rule, aspiration is most often observed at functional or organic lesion of a reflex arc responsible for defense reactions of the upper or lower respiratory tracts interfering aspiration. Development of such state should be expected at an anesthesia, various damages (injuries, tumors, intoxications, vascular disorders) of the central nervous system, diseases of peripheral nerves, influence of a number of the mechanical factors promoting aspiration (nazogastralny sounding), injuries of the person and neck, tumors of a gullet, trachea, etc.

Treatment of Aspiration pneumonia:

At full obstruction of respiratory tracts owing to aspiration of a foreign body the immediate help for recovery of their passability is required. In the USA Geymlikh's method is for this purpose used: tolchkoobrazny pressing in subphrenic area. If the foreign body remains in the lower respiratory tracts, for its extraction, depending on the size, the bronkhoskopiya is carried out, and at its inefficiency – a thoracotomy.

Oxygenotherapy – also necessary component of initial therapy. In hard cases the intubation of a trachea and carrying out the artificial ventilation of the lungs (AVL) with the increased respiratory volume is shown. The Sanatsionny bronkhoskopiya is recommended in case of sanitation of respiratory tracts from foreign bodys then actions for stabilization of a hemodynamics, performing infusional therapy are necessary.
Methods of treatment acute respiratory a distress syndrome owing to aspiration include extracorporal membrane oxygenation, IVL, replacement therapy by surfactant and biochemical, immunological means of correction of cellular damage.
At the chemical pneumonitis developing at massive aspiration carrying out ABT is not required. Preventive prescription of antibiotics is also not shown in view of high probability of formation of resistant strains and unproven efficiency in the prevention of pneumonia.
The main component of treatment of the developed AP is early ABT. The choice of an antibiotic depends on weight of AP, an environment in which there was pneumonia, and existence or lack of risk factors of colonization of respiratory tracts gram-negative microorganisms. Generally are guided by the empirical choice of drugs. Taking into account that the main reason for AP which arose out of a hospital are anaerobe bacterias, the appointed antibiotics have to be active in relation to them.
In cases of extra hospital AP researchers recommend to include in the scheme of empirical ABT ingibitorzashchishchenny β-lactams (amoxicillin/clavulanate), to tsefoperazon/sulbakta or a β-laktamny antibiotic in a combination with metronidazole. Ingibitorzashchishchenny β-lactams (for example amoxicillin/clavulanate is active concerning aerobic gram-positive cocci, enterobakteriya and anaerobe bacterias) are choice drugs for monotherapy of the Apostle. Despite good anti-anaerobic activity of in vitro, metronidazole it is not necessary to apply in the monotherapy mode.
Modern ftorkhinolona, such as levofloxacin and moxifloxacin, create high bactericidal concentration in tissue of a lung and an endobronchial secret and have a certain anti-anaerobic activity therefore they can be used as reserve drugs, especially at an allergy to β-lactams. Clindamycin (intravenously 600 mg each 8 h with the subsequent transition to reception of per os of 300 mg each 6 h) which has bigger activity concerning anaerobe bacterias in comparison with penicillin can be drug of the choice.
Intrahospital AP demands immediate empirical deeskalatsionny ABT. Special approach to the choice of antibacterial drug because of high probability of development of the infectious process caused by polyresistant nozokomialny strains of aerobic gram-negative bacteria is necessary (representatives of Enterobacteriaceae and nonfermentative bacteriums).
In intensive care unit and an intensive care, and also at development of pneumonia in the patients who are in a hospital more than 5 days, "problem" activators are P. aeruginosa and Acinetobacter spp. At patients in a coma after a severe injury of the central nervous system in the presence of dekompensirovanny renal pathology and a diabetes mellitus, polyresistant S. aureus joins the pathogens stated above. Drugs of the choice are tsefepy in a combination with metronidazole, a ceftazidime in a combination with metronidazole or clindamycin, to piperatsillin/tazobakta, tsefoperazon/sulbakta or тикарциллин / clavulanate. The combination of an aztreonam with clindamycin eliminirut probable causative agents of pneumonia and is alternative therapy of the Apostle.
With the established high frequency of metitsillinorezistentny stafilokokk and existence bacteriological of the confirmed infection caused by polyresistant stafilokokka (at positive crops from a nasopharynx, at the accompanying staphylococcal infection of other localizations), it is necessary to include glycopeptides, for example Vancomycinum in the scheme ABT or тейкопланин.

In general at intrahospital AP schemes of treatment of nozokomialny pneumonia are acceptable. Bystry (in 1-2 days) the response to antimicrobic therapy in the form of positive dynamics of the somatic status and signs of permission of intra pulmonary infiltrate testifies to OHP. In these cases it is possible to stop further use of antibiotics. According to J. Bartlett, in the first 48-72 h stabilization of clinical symptoms is observed. Further it is necessary to estimate efficiency of therapy and to solve, to continue treatment or to replace antibiotics. With results of a bacteriological research it is possible to appoint etiotropic treatment. However the long febrile period and progressing of pulmonary infiltration demonstrate development of abscessing or about inadequacy of ABT because of resistance of the activator to the appointed antibiotics (for example superinfection resistant strains of P. aeruginosa).
The way of introduction of an antibiotic is defined by weight of the Apostle. Patients with heavy pneumonia and the complicated forms of a disease have to receive parenteral therapy. At less heavy current purpose of peroral drugs is possible. The answer to ABT at 80% of patients with AP is noted during the first 5 days of treatment.
Course ABT duration at patients with AP without abscess or an empyema makes about 14 days. In the presence of abscess fever can remain 5-10 days and more, despite adequate therapy.
Patients with abscesses and empyemas need purpose of parenteral therapy before achievement of clinical effect: decrease in fever, definition of a tendency to normalization of quantity of leukocytes, reduction of expressiveness of cough and диспноэ. On condition of normal absorption from a digestive tract transition to therapy by per os antibiotics is possible (clindamycin of 300 mg each 6 h; amoxicillin of 500 mg each 8 h + metronidazole of 500 mg each 6-8 h; amoxicillin / clavulanate of 625 mg each 8 h). The recommended ABT duration at patients with abscess of lungs and an empyema of a pleura makes 2-3 months.
Drainage of abscesses, fibrobronkhoskopiya, transbronchial catheterization, transdermal catheterization of a cavity of peripheral abscess belong to surgical methods of treatment of AP. Surgical intervention is shown at the big sizes of abscess (more than 6 cm) and at a complication by its pulmonary bleeding, and also in case of formation of a bronchopleural fistula.