Nosocomial pneumonia is a lung infection that developed two or more days after the patient’s admission to the hospital, in the absence of signs of the disease at the time of hospitalization. The manifestations of nosocomial pneumonia are similar to those in other forms of pneumonia: fever, cough with sputum, tachypnea, leukocytosis, infiltrative changes in the lungs, etc., however, they may be weakly pronounced, erased. The diagnosis is based on clinical, physical, radiological and laboratory criteria. Treatment includes adequate antibiotic therapy, airway sanitation (lavage, inhalations, physiometrics), infusion therapy.
J18 Pneumonia without specifying the causative agent
Nosocomial (hospital) pneumonia is an infection of the lower respiratory tract acquired in a hospital, the signs of which develop no earlier than 48 hours after the patient is admitted to a medical institution. Nosocomial pneumonia is one of the three most common nosocomial infections, second in prevalence only to wound infections and urinary tract infections. Disease develops in 0.5-1% of patients undergoing treatment in hospitals, and in patients of intensive care and intensive care units it occurs 5-10 times more often. Mortality in nosocomial pneumonia is extremely high – from 10-20% to 70-80% (depending on the type of pathogen and the severity of the patient’s background condition).
Nosocomial pneumonia causes
The main role in the etiology of nosocomial bacterial pneumonia belongs to gram–negative flora (Pseudomonas aeruginosa, Klebsiella, E. coli, proteus, serracia, etc.) – these bacteria are found in the secret of the respiratory tract in 50-70% of cases. In 15-30% of patients, methicillin-resistant Staphylococcus aureus is the leading pathogen. Due to various adaptive mechanisms, these bacteria develop resistance to most known antibacterial agents. Anaerobes (bacteriodes, fusobacteria, etc.) are etiological agents of 10-30% of nosocomial pneumonia. Approximately 4% of patients develop legionella pneumonia – as a rule, it proceeds according to the type of mass outbreaks in hospitals, the cause of which is the contamination of air conditioning and water supply systems with legionella.
Nosocomial infections of the lower respiratory tract caused by viruses are diagnosed much less frequently than bacterial pneumonia. Among the pathogens of nosocomial viral pneumonia, the leading role belongs to influenza A and B viruses, MS virus, in patients with weakened immunity – cytomegalovirus.
Long-term hospitalization, hypokinesia, uncontrolled antibiotic therapy, elderly and senile age are common risk factors for infectious complications from the respiratory tract. The severity of the patient’s condition due to concomitant chronic heart disease, postoperative period, injuries, blood loss, shock, immunosuppression, coma, etc. is of significant importance. Medical manipulations can contribute to the colonization of the lower respiratory tract by microbial flora: endotracheal intubation and reintubation, tracheostomy, bronchoscopy, bronchography, etc. The main ways of pathogenic microflora entering the respiratory tract are aspiration of oropharyngeal secretions or stomach contents, hematogenic spread of infection from distant foci.
Ventilator-associated pneumonia occurs in patients who are on a ventilator; at the same time, every day spent on apparatus breathing increases the risk of developing nosocomial pneumonia by 1%. Postoperative, or congestive pneumonia, develops in immobilized patients who have undergone severe surgical interventions, mainly on the thoracic and abdominal cavities. In this case, the background for the development of pulmonary infection is a violation of the drainage function of the bronchi and hypoventilation. The aspiration mechanism of the occurrence of nosocomial pneumonia is characteristic of patients with cerebrovascular disorders, who have violations of cough and swallowing reflexes; in this case, not only infectious agents have a pathogenic effect, but also the aggressive nature of gastric aspirate.
According to the timing of occurrence, hospital infection is divided into early and late. Nosocomial pneumonia, which occurred in the first 5 days after admission to the hospital, is considered early. As a rule, it is caused by pathogens present in the patient’s body even before hospitalization (St. aigeis, St. pneumoniae, H. influenzae, etc. representatives of the microflora of the upper respiratory tract). Usually these pathogens show sensitivity to traditional antibiotics, and pneumonia itself proceeds more favorably.
Late nosocomial pneumonia manifests after 5 or more days of inpatient treatment. Its development is due to the hospital strains themselves (methicillin-resistant St. aegeis, Acinetobacter spp., P. aegidinosa, Enterobacteriaceae, etc.), showing highly virulent properties and polyresistance to antimicrobial drugs. The course and prognosis of late nosocomial pneumonia are very serious.
Taking into account causal factors, there are 3 forms of nosocomial respiratory tract infection:
- ventilator-associated pneumonia
- postoperative, or congestive pneumonia
- aspiration pneumonia
At the same time, quite often different forms are layered on top of each other, further aggravating the course of nosocomial pneumonia and increasing the risk of death.
Nosocomial pneumonia symptoms
A feature of the course of nosocomial pneumonia is the erasure of symptoms, which makes it difficult to recognize a lung infection. First of all, this is due to the general severity of the condition of patients associated with the underlying disease, surgery, old age, comatose state, etc.
Nevertheless, in some cases, nosocomial pneumonia can be suspected on the basis of clinical data: a new episode of fever, an increase in the amount of sputum / tracheal aspirate or a change in their nature (viscosity, color, smell, etc.). Patients may complain of the appearance or intensification of cough, shortness of breath, chest pain. In patients who are in a serious or unconscious state, attention should be paid to hyperthermia, increased heart rate, tachycardia, signs of hypoxemia. The criteria for a severe infectious process in the lungs are signs of severe respiratory (BH > 30/min.) and cardiovascular insufficiency (heart rate > 125 /min., blood pressure < 100/60 mm Hg.), impaired consciousness, bilateral or multilobar lung damage, etc. At the same time, it is necessary to exclude possible non-infectious causes of cardiopulmonary disorders: pneumothorax, acute respiratory distress syndrome, pulmonary edema, PE, lung infarction, etc. Complications of nosocomial pneumonia are most often lung abscess, pleural empyema, sepsis.
A complete diagnostic examination in case of suspected nosocomial pneumonia is based on a combination of clinical, physical, instrumental (lung x-ray, chest CT), laboratory methods (blood test, biochemical and gas composition of blood, sputum removal).
To make an appropriate diagnosis, pulmonologists are guided by the recommended criteria, including: fever above 38.3 ° C, increased bronchial secretion, purulent sputum or bronchial secretion, cough, tachypnea, bronchial breathing, wet wheezing, inspiratory crepitation. The fact of nosocomial pneumonia is confirmed by radiological signs (the appearance of fresh infiltrates in the lung tissue) and laboratory data (leukocytosis >12,0×109 / l, rod shift >10%, arterial hypoxemia Ra02 < 60 mmHg, Sa02 < 90%.).
In order to verify the probable pathogens of nosocomial pneumonia and determine antibiotic sensitivity, a microbiological study of the secret of the tracheobronchial tree is performed. For this purpose, not only samples of freely coughed sputum are used, but also tracheal aspirate, bronchial flushing water. Along with the cultural isolation of the pathogen, PCR research is widely used.
Nosocomial pneumonia treatment
The complexity of the treatment of nosocomial pneumonia lies in the polyresistance of pathogens to antimicrobial drugs and the severity of the general condition of patients. In almost all cases, the initial antibiotic therapy is empirical, i.e. it begins even before the microbiological identification of the pathogen. After establishing the etiology of nosocomial pneumonia, the drug can be replaced with a more effective one against the detected microorganism.
The drugs of choice for nosocomial pneumonia caused by E.Coli and K. pneumoniae are cephalosporins of the III-IV generation, inhibitor-protected penicillins, fluoroquinolones. Pseudomonas Aeruginosa is sensitive to the combination of III-IV generation cephalosporins (or carbapenems) with aminoglycosides. If hospital strains are represented by St. aigees, the appointment of cefazolin, oxacillin, amoxicillin with clavulanic acid, etc. is required. Voriconazole or caspofungin is used for the treatment of pulmonary aspergillosis.
In the initial period, the intravenous route of administration of the drug is preferred, in the future, with positive dynamics, it is possible to switch to intramuscular injections or oral administration. The duration of the course of antibiotic therapy in patients with nosocomial pneumonia is 14-21 days. Evaluation of the effectiveness of etiotropic therapy is carried out according to the dynamics of clinical, laboratory and radiological indicators.
In addition to systemic antibiotic therapy, in case of nosocomial pneumonia, important attention is paid to the rehabilitation of the respiratory tract: bronchoalveolar lavage, inhalation therapy, tracheal aspiration. Patients are shown an active motor mode: frequent change of position and sitting down in bed, exercise therapy, breathing exercises, etc. Additionally, detoxification and symptomatic therapy is carried out (infusion of solutions, administration and administration of bronchodilators, mucolytics, antipyretic drugs). For the prevention of deep vein thrombosis, heparin or wearing compression knitwear is prescribed; in order to prevent stress ulcers of the stomach, H2 blockers, proton pump inhibitors are used. Intravenous immunoglobulins may be indicated for patients with severe septic manifestations.
Prognosis and prevention
Clinical outcomes of nosocomial pneumonia can be resolution, improvement, ineffectiveness of therapy, relapse and death. Nosocomial pneumonia is the main cause of mortality in the structure of nosocomial infections. This is due to the complexity of its timely diagnosis, especially in elderly, weakened patients, comatose patients.
Prevention of nosocomial pneumonia is based on a complex of medical and epidemiological measures: treatment of concomitant foci of infection, compliance with the sanitary and hygienic regime and infection control in medical institutions, prevention of the transfer of pathogens by medical staff during endoscopic manipulations. Early postoperative activation of patients, stimulation of sputum clearing is extremely important; severe patients need adequate oropharyngeal toilet, constant aspiration of tracheal secretions.
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