Severe community-acquired pneumonia

Community-acquired pneumonia is the most common human infectious disease. The incidence of community-acquired pneumonia in Europe ranges from 2 to 15 per 1000 people per year, in Russia to 10-15 per 1000 people per year. This indicator is significantly higher in elderly patients 25-44 per 1000 people per year in patients older than 70 years and up to 68-114 per 1000 people per year in elderly patients in homes for people with disabilities, nursing homes In the United States annually register 5-6 million cases EP, with 20% of patients need hospitalization. According to approximate estimates, for every 100 cases of community-acquired pneumonia (community-acquired pneumonia complicated by acute respiratory failure, community-acquired pneumonia complicated by severe sepsis or septic shock), there are about 20 patients in need of inpatient treatment, of which about 10% are under conditions of ICU.

ICD-10 code

• J13 Pneumonia caused by Streptococcus pneumoniae
• J14 Pneumonia caused by Haemophilus influenzae
• J15 Bacterial pneumonia, not elsewhere classified
  • J15.0 Pneumonia caused by Klebsiella pneumoniae
  • J15.1 Pneumonia caused by Pseudomonas spp.
  • J15.2 Pneumonia caused by Staphylococcus spp.
  • J15.6 Pneumonia caused by other aerobic gram-negative bacteria
  • J15.7 Pneumonia caused by Mycoplasma pneumoniae
  • J15.8 Other bacterial pneumonia
  • J15.9 Bacterial pneumonia, unspecified etiology
• J16.0 Pneumonia caused by Chlamydia spp.
• J16.8 Pneumonia caused by other established pathogens
• A48.1 Legionnaires' disease

Assessment of the severity and risk of death of community-acquired pneumonia

An objective assessment of the severity of the patient's condition is a necessary tool for determining the tactics of patient management, resolving questions about its transportation, the optimal place for patient therapy (specialized department, intensive care unit, etc.), for comparing the outcomes of the disease depending on therapies, the quality of care .

The use of pneumonia severity scales, as well as the recommendations of conciliation conferences of respiratory communities, can significantly reduce the cost of treatment, and significantly reduce the failure of therapy.

One of the most common scales for assessing the severity and prognosis of community-acquired pneumonia is the PSI (Pneumonia Severity Index) scale, proposed by Fine in 1997. Using this algorithm, it is possible to classify patients according to the available risk factors. According to this scale, the main criteria for the severity of pneumonia are age, concomitant pathology, changes in vital parameters. However, PSI counts require additional laboratory studies, gas analysis of blood and lung radiography. The more points the patient has, the more likely the poor prognosis is. Patients belonging to the fifth class, as a rule, have severe pneumonia and require intensive therapy.

Pneumonia Seventy Index Scale for Severity of Patients with Community-Acquired Pneumonia

Characteristics of patients	Points	Characteristics of patients	Points
Age of men	Age in years	Respiratory rate> 30 per minute	+20
Age of women	Age in years minus 10	Blood pressure <90 mm Hg	+20
Stay in a nursing home	10	Body temperature <36 ° C or> 40 ° C	+15
Malignant tumors	+30	Hematocrit <30%	+30
Diseases of the liver	+20	PH <7.35	+30
Congestive heart failure	10	Urea> 11 mmol / l	+20
Cerebrovascular diseases	10	Sodium serum of blood <130 meq / L	+20
Kidney Diseases	10	Hematocrit <30%	10
General cerebral symptoms	+30	RAO 2 <60 mm Hg	10
Heart Rate> 125 per minute	10	Pleural effusion	10

Lethality of patients with community-acquired pneumonia, depending on the evaluation of patients on the scale Pneumonia Severity Index

Risk classes	Score	Mortality,%	Place of treatment
I	Patients over 50 years old, without concomitant diseases and changes in vital signs	0.1	Ambulatory
II	<70	0.6	Ambulatory
III	71-90	0.9	Hospital
IV	91-130	9.3	Hospital
V	> 130	27.0	Hospital

The CURB-65 index consists of five indicators (four clinical and one laboratory), which have been shown to have a high prognostic potential for pneumonia in hospitalized patients. These indicators reflect age, ODN, and signs of severe sepsis or septic shock. Patients who have 0-1 points are referred to a group of minimal risk (lethality about 1.5%), while those who have 2 or 3-5 points, the risk of death 9 and 22%, respectively. Patients with 4-5 points should receive therapy in conditions of ICU. The simplified CRB-65 index (without the urea index as a rating criterion) is also well validated and has a high predictive value. The indices of CURB-65 and CRB-65 have advantages over the PSI index, they are based on the severity of EP, and not on the concomitant pathology, which avoids underestimating the severity of pneumonia in young patients or possible errors due to undiagnosed comorbidities, easier to calculate.

Relatively recently, a new PS-CURXO-80 scale was proposed, based on eight indicators. According to preliminary data, this scale is a more reliable instrument for determining indications for hospitalization of patients in the ICU than the PSI and CURB-65 scales.

[1], [2], [3], [4], [5], [6], [7], [8]

Classification and definition

Modern classifications subdivide pneumonia into several groups depending on the conditions of the onset of the disease:

• Community-acquired pneumonia (acquired outside health facilities),
• Nosocomial (hospital) pneumonia (acquired in medical institutions),
• aspiration pneumonia,
• pneumonia in persons with immunodeficiency states.

This classification is justified by various causative factors of pneumonia and different approaches to the choice of antibiotic therapy.

All out-of-hospital pneumonia can be conditionally divided into three groups according to the degree of severity:

• pneumonia, which does not require hospitalization (patients with mild pneumonia can receive therapy in outpatient settings, lethality does not exceed 1-5%),
• pneumonia, which require hospitalization of patients in the hospital (patients with background chronic diseases and severe clinical symptoms, the risk of mortality of hospitalized patients reaches 12%),
• pneumonia, which requires hospitalization of patients in the ICU (patients with severe community-acquired pneumonia, lethality is about 40%).

Thus, severe community-acquired pneumonia is a pneumonia characterized by a high risk of death and requires management of patients in the ICU.

The main signs of severe community-acquired pneumonia, which determine the decision to send a patient to the ICU:

• respiratory insufficiency,
• severe sepsis or septic shock,
• prevalence of pulmonary infiltrates according to chest radiography.

The American Thoracic Society proposed criteria for severe community-acquired pneumonia, a new modification of the criteria is given below (GOBA / ATB, 2007)

The presence of at least three small or one large criterion confirms a severe comorbidity. Pneumonia, i.e. Pneumonia, which requires the hospitalization of a patient in the ICU.

[9],

Criteria for severe community-acquired pneumonia

Small criteria assessed at hospitalization:

• respiratory rate> 30 per minute,
• PaO ₂ / FiO ₂ <250 mm. Gt; art.
• multilobar infiltrates (according to the chest X-ray),
• confusion or disorientation,
• uremia (blood urea nitrogen> 20 mg / dL),
• leukopenia (blood leukocytes <4000 in 1 mm ³ ) as a consequence of infection,
• thrombocytopenia (blood platelets <100 in mm ³ ),
• hypothermia (body temperature <36 ° C),
• hypotension (systolic blood pressure <90 mmHg or diastolic blood pressure <60 mmHg), if solutions are to be administered.

Large criteria assessed at hospitalization or during the entire period of the disease:

• the need for mechanical ventilation,
• septic shock with the need for vasopressors.

Other potential criteria include hypoglycemia (in patients without diabetes), alcoholism, hyponatremia, metabolic acidosis or increased lactate levels, cirrhosis, aspension.

[10], [11], [12], [13]

How is severe pneumonia recognized?

The most common symptoms of community-acquired pneumonia are:

• cough,
• production of sputum,
• fever,
• dyspnea,
• pain in the chest,
• chills,
• hemoptysis.

Less common symptoms:

• headache,
• weakness,
• myalgia,
• arthralgia,
• syncope,
• diarrhea,
• nausea,
• vomiting.

Physical examination reveals fever, tachypnea, cyanosis, wheezing, dullness of percussion sound, increased voice jitter and bronchophony, signs of pleural effusion.

Classical signs of pneumococcal pneumonia:

• sudden onset (24-48 h),
• high fever,
• chills,
• pleural pain,
• separation of rusty sputum,
• In the course of the examination, labial herpes are often found, signs of pulmonary consolidation and crepitus.

The clinical picture of pneumonia in elderly patients may differ markedly from that in young patients. In patients older than 75 years, fever and cough are absent in 15% and 40%, respectively. Sometimes the only signs of pneumonia in elderly patients are tachypnea, tachycardia and confused consciousness (50-75% of patients).

Radiography of the chest - the "gold standard" for diagnosing pneumonia. The syndrome of lobar lobar seal (dense homogeneous infiltrates) with air bronchograms is typical for pneumonia caused by "typical" bacteria. Bilateral basal interstitial or reticulonodular infiltrates are more common in pneumonia caused by atypical microorganisms. However, the x-ray picture, like the clinical data, does not allow to establish reliably the etiology of pneumonia.

Regardless of the type of pathogen, most often the inflammatory process affects the lower lobes of the lungs. In pneumococcal pneumonia, complicated by bacteremia, more frequent involvement of several lobes and the presence of pleural effusion are observed in the process. Characteristic radiographic findings in staphylococcal pneumonia, multidole lesions, abscessing, pneumatology, spontaneous pneumothorax. For pneumonia caused by K. Pneumoniae, the involvement of upper lobes (more often on the right) and the destruction of the pulmonary parenchyma with the formation of abscesses are more typical. The formation of abscesses is also observed in pneumonia caused by anaerobes, fungi, mycobacteria, and is practically not found in pneumonia caused by S. Pneumoniae, M. Pneumoniae, C. Pneumoniae.

Quite rarely, chest x-rays in patients with pneumonia receive false-negative results:

• when dehydrating patients,
• with neutropenia,
• with pneumocystis pneumonia,
• in the early stages of the disease (up to 24 hours from the development of the disease).

In difficult cases, it is possible to perform CT of the chest, as this method is more sensitive.

Laboratory methods of research

Laboratory tests in the ICU should include a gas analysis of arterial blood and basic blood counts. A general blood test is a routine diagnostic test in patients with pneumonia. The number of blood leukocytes more than 15x10 ⁹ / l is a strong argument in favor of the bacterial nature of pneumonia (often pneumococcal), although the lower values do not exclude bacterial nature. Some biochemical tests (urea, glucose, electrolytes, liver function markers) are usually performed to assess the severity of the disease and identify concomitant pathology (renal or hepatic insufficiency).

C-reactive protein can not be used in differential diagnosis of bacterial and non-bacterial pneumonia. Its level is weakly correlated with its severity. But the clinical course of pneumonia corresponds well to changes in the concentration of C-reactive protein. C-reactive protein, IL-6 and procalcitonin have an independent prognostic value.

Microbiological examination

Microbiological studies can help in the choice of treatment, especially in the most severe patients. All patients with severe pneumonia hospitalized in the ICU are recommended to conduct the following microbiological studies:

• a study of blood,
• Gram stain and sputum culture or material from the lower respiratory tract,
• analysis of pleural fluid (if any),
• study of Legionella spp and S. Pneumoniae antigens in urine,
• a study of the material from the lower sections of the respiratory tract by direct immunofluorescence for the detection of the influenza virus and RS virus in the winter,
• examination of the material from the lower respiratory tracts by PCR or culture for the detection of Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella spp. With availability of reliable tests,
• serological tests on Legionella spp. And atypical pathogens initially and in dynamics in the absence of PCR diagnostics.

A microbiological study of blood (blood taken from two sites) should be carried out before any antibiotic therapy and as early as possible. In total, a positive culture of blood is detected in 4-18% of cases, with the main pathogen being S. Pneumoniae.

A sputum specimen obtained by deep coughing is considered suitable for the analysis. In patients who are on artificial ventilation, a tracheobronchial aspirate is used for bacteriological examination. Negative results of crops when using these methods are obtained in 30-65% of all cases. Certain problems are related to the fact that 10-30% of patients with pneumonia do not have sputum, and up to 15-30% of patients have already received antibiotics before taking sputum for analysis.

As the express methods of microbiological diagnosis, methods for detecting antigens of microorganisms in urine are used. Currently, tests are available to detect antigens of S. Pneumoniae and Legionella pneumophila serogroup 1 (responsible for 80% of all cases of legionella infection), the sensitivity of the methods is 50-84%, and the specificity is more than 90%.

As a rapid method for the isolation of certain microorganisms (Chlamydophila, Mycoplasma and Legionella) from sputum and aspirate, the PCR method can be used. However, this method is still poorly standardized, and interpretation of the results can be difficult.

Serological methods do not help in the initial evaluation of the etiological factor of pneumonia, and they are usually not recommended for routine use. They can be of great importance for retrospective analysis. Serological tests are usually conducted to identify atypical bacteria and include an assessment of the level of IgG antibodies in paired sera (at intervals of 2-4 weeks). An increase in the titer of cold hemagglutinins more than 1 64 is observed in 30-60% of cases in patients with M. Pneumoniae infection. However, this test becomes positive only a week after the onset of the disease. To achieve the diagnostic titer of IgM to M pneumoniae, it is also necessary about a week, and for reaching the diagnostic titer of IgM to C. Pneumoniae - about three weeks. Detection of a single IgG titer to Legionella spp. More than 1 256 are considered sufficient to detect acute legionellosis infection, but the sensitivity of the method is only 15%.

Lack of analysis of sputum and aspirate - contamination of the specimen with the microflora of the oropharynx. Overcoming this disadvantage are such methods as transtracheal aspiration, transthoracic aspiration with a thin needle and bronchoscopy with the implementation of a protected brushing biopsy and BAL. The first two methods are practically not used in practice, since they are quite traumatic and are accompanied by the development of side effects. Bronchoscopic methods are used mainly in patients with hospital pneumonia, with community-acquired pneumonia used only in severe patients. When carrying out a protected brush biopsy, a number of colony-forming units in 1 ml more than 10 ^{3 are} considered to be a diagnostic titre of bacteria for the diagnosis of pneumonia , while more than 10 ⁴ for the BALF .

Microbiology of community-acquired pneumonia

Microbiological identification of the pathogen is possible only in 40-60% of cases of all pneumonias. The structure of the causative agents of EP, based on the results of prospective studies conducted in Europe, is presented below.

Etiology of community-acquired pneumonia

Pneumonia, in which there is no need to hospitalize a patient	Pneumonia, which requires hospitalization in a hospital	Pneumonia, which requires hospitalization in the ICU
Streptococcus pneumoniae	Streptococcus pneumoniae	Streptococcus pneumoniae
Mycoplasma pneumoniae	Mycoplasma pneumoniae	Staphylococcus aureus
Haemophilus influenzae	Chlamydophila pneumoniae	Legionella spp
Chlamydophila pneumoniae	Haemophilus influenzae	Gram-negative bacteria
Viruses (a)	Legionella spp
	Anaerobes (with aspiration)
	Viruses (a)

Note a - influenza A and B viruses, adenoviruses, respiratory syncytial virus, parainfluenza virus.

Streptococcus pneumoniae is the main causative agent of severe community-acquired pneumonia (about 22%), it accounts for up to two-thirds of all causes of pneumonia with bacteremia Staphylococcus aureus, Legionella pneumophila and Gram-negative bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa, etc.) also play a significant role in the genesis of heavy community-acquired pneumonia. Legionella spp infections are found mainly in regions with warm climates (Mediterranean countries) and quite rarely in the Nordic countries. The role of anaerobic microorganisms in the genesis of community-acquired pneumonia is small, but significantly increases with aspiration pneumonia - up to 50% of all causes Viral infections cause about 5% of all severe community-acquired pneumonia. At the same time, the influenza virus is of major importance, the smaller is parainfluenza viruses, adenoviruses, respiratory syncytial virus. Viral pneumonia distinguishes seasonality of occurrence mainly in the autumn-winter time.

Knowing the epidemiological factors and the geographical situation can help in assuming the etiologic factor of community-acquired pneumonia.

Risk factors for the development of community-acquired pneumonia of known etiology

Risk factors	Pathogens
COPD and / or bronchocytosis	Haemophilus influenzae, gram-negative enterobacteria, Pseudomonas aeruginosa
Recent hospitalization	Gram-negative enterobacteria, Pseudomonas aeruginosa
Recent treatment with antibiotics	Gram-negative enterobacteria, Pseudomonas aeruginosa
Small aspiration	Mixed infection, anaerobes
Massive aspiration	Gram-negative enterobacteria, Pseudomonas aeruginosa, anaerobes
Flu	Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae
Contact with cattle	Coxiella burnetii
Contact with birds	Chlamydia psittaci
Use of intravenous drugs	Staphylococcus aureus (methicillin-sensitive or methicillin-resistant)
Recent trips to the Mediterranean coast	Legionella spp
Recent trips to the Middle East or the South of the United States	Histoplasma cAPSulatum
Long-term treatment with glucocorticoids	Pseudomonas aeruginosa, Aspergillus spp

The proportion of strains of S. Pneumoniae resistant to penicillin in some countries exceeds 60%. According to Russian studies, the incidence of pneumococcal strains resistant to penicillin does not exceed 10%. The resistance of pneumococci to macrolides in Russia is also low (6-9%), but at the same time the resistance to tetracyclines and co-trimoxazole is very high (30 and 41% respectively).

Risk factors for the development of pneumococcal resistance to antibiotics:

• the age of patients over 65 years,
• stay in nursing homes,
• therapy with β-lactam antibiotics for the last 3 months,
• alcoholism,
• multiple concomitant diseases.

The level of resistance of Haemophilus influenzae to aminopenicillins in our country is also small and does not exceed 5%, however, about 30% of all strains of H. Influenzae are insensitive to co-trimoxazole.

Treatment of severe community-acquired pneumonia

Objectives of treatment

Eradication of the pathogen, resolution of the clinical picture of community-acquired pneumonia, provision of adequate gas exchange, therapy and prevention of complications.

Antibiotic therapy

Initial therapy should be empirical. The rapid onset of adequate antibiotic therapy is a key to successful treatment. Treatment should be started within the first 2-4 hours after hospitalization of the patient in a hospital and within an hour from the moment of admission to the ICU.

The initial choice of the antimicrobial preparation is carried out empirically (that is, until the results of the microbiological study are obtained), since:

• at least in half the cases, the responsible microorganism can not be detected even with the help of the latest modern research methods, and the existing microbiological methods are rather nonspecific and insensitive,
• any delay in etiotropic therapy of pneumonia accompanies an increased risk of complications and lethality of pneumonia, while timely, correctly selected empirical therapy can improve the outcome of the disease,
• assessment of the clinical picture, radiological changes, concomitant diseases, risk factors and the severity of pneumonia in most cases allows us to make the right decision about the choice of adequate therapy.

A mandatory requirement is the adequacy of initial antibiotic therapy, because adverse outcomes are often associated with inappropriate antibiotic prescribing. Initial empirical antibacterial therapy should consider:

• the most likely spectrum of pathogens depending on the severity of pneumonia and additional risk factors,
• local characteristics of antibacterial resistance,
• tolerability and toxicity of antibiotics for a particular patient.

In severe pneumonia, a combination of third generation cephalosporins (or amoxicillin in combination with clavulanic acid) and macrolides is prescribed as the starting therapy. According to several retrospective studies, such a regimen of therapy may accompany a decrease in mortality, which is explained not only by the activity of the combination of drugs to typical and atypical microorganisms, but also by the ability of macrolides to reduce the pro-inflammatory effect of bacterial products. An alternative regimen is a combination of third generation cephalosporins and respiratory fluoroquinolones. If you suspect a infection with Legionella spp. Parenteral rifampicin is added to these preparations.

For patients with severe community-acquired pneumonia, the identification of risk factors for Gram-negative enterobacteria and / or P. Aeruginosa is essential, since it requires another initial empirical antibiotic therapy. According to one study, the presence of three of the four risk factors (COPD / bronchiectasis, recent hospitalizations, recent antibiotic therapy and presumed aspiration) means a 50 percent risk of infection with gram-negative enterobacteria or P. Aeruginosa. Infection with P. Aeruginosa should be borne in mind in patients permanently receiving glucocorticoid therapy (> 10 mg prednisolone per day), as well as in any smoking patient with rapidly progressing pneumonia.

Empirical antimicrobial therapy in patients with community-acquired pneumonia with a high risk of P. Aeruginosa should include third generation cephalosporins with anti-synergic activity (ceftazidime, cefepime) or carbopenems (imipenem, meropenem) in combination with ciprofloxacin or aminoglycosides.

Recommended treatment regimens for patients with severe community-acquired pneumonia

There are no risk factors for P aeruginosa infection	Cefotaxime IV or ceftriaxone iv or amoxicillin with clavulanic acid iv and macrolide iv (azithromycin or clarithromycin) Cefotaxime IV or ceftriaxone IV or amoxicillin with clavulanic acid IV and respiratory fluoroquinolone IV (moxifloxacin or levofloxacin)
Risk factors for infection with P Aeruginosa	Antisignagic beta-lactam iv (ceftazidime or cefepime or piperacillin / tazobactam or imipenem or meropenem) and fluoroquinolone iv (ciprofloxacin or levofloxacin) Antisignagic beta-lactam iv (see above) and aminoglycoside with / a with azithromycin Antisinogenous beta lactam IV (see above) and aminoglycoside IV with respiratory fluoroquinolone IV (moxifloxacin or levofloxacin)

When suspected of aspiration, severe community-acquired pneumonia is prescribed amoxicillin with clavulanic acid, cefoperazone with sulbactum, ticarcillin with clavulanic acid, piperacillin / tazobactam, carbapenems (meropenem, imipenem). Combinations of various pathogens can be found in 5-38% of patients, but their effect on the outcome of the disease has not yet been established.

At the same time, patients with severe community-acquired pneumonia should strive to refine the etiologic diagnosis, since such an approach may influence the outcome of the disease. Advantages of "directional" therapy decrease the number of prescribed drugs, reduce the cost of treatment, reduce the number of side effects of therapy and reduce the selection potential of resistant strains of microorganisms. When specific pathogens are isolated, appropriate treatment is performed.

Recommended treatment for identified specific pathogens

Causative agent	Recommended treatment
Moderately resistant Streptococcus pneumoniae <2 mg / dL	High doses of amoxicillin, third-generation cephalosporins, respiratory fluoroquinolones
Highly resistant Streptococcus pneumoniae> 2 mg / dL	Respiratory fluoroquinolones, vancomycin, linezolid
Methicillin-sensitive Staphylococcus aureus	Second-generation cephalosporins, clindamycin, respiratory fluoroquinolones
Methicillin-resistant Staphylococcus aureus	Vancomycin, possibly rifampicin, linezolid
Ampicillin-resistant Haemophilus influenzae	Amoxicillin / clavulanate and amoxicillin / sulbactam, respiratory fluoroquinolones
Mycoplasma pneumoniae	Macrolides, respiratory fluoroquinolones, doxycycline
Chlamydia pneumoniae	Macrolides, respiratory fluoroquinolones, doxycycline
Legionella spp	Respiratory fluoroquinolones, macrolides, possibly rifampicin, azithromycin
Coxiella burnetii	Macrolides, respiratory fluoroquinolones
Enterobactenaceae	Third-generation cephalosporins, carbopenems (choice drugs in the case of beta-lactamase producers of the extended spectrum), inhibitor-protected beta-lactams, fluoroquinolones
Pseudomonas aeruginosa	Antisignagic beta-lactam and ciprofloxacin or lefofloxacin
Acmetobacter baumannu	Third generation cephalosporins and aminoglycosides
Burkholderia pseudomallei	Carbopenems, ceftazidime, fluoroquinolones, co-trimoxosol
Anaerobes (with aspiration)	Inhibitor-protected beta-lactams, clindamycin, carbopenems

The answer to antimicrobial therapy depends on the immune reactivity of the organism, the severity of the disease, the causative pathogen, the length of pneumonia according to the radiographic picture. Subjective response to antibiotic therapy is usually observed within 1-3 days from the start of therapy. The objective response includes assessment of fever, clinical symptoms, laboratory indicators and radiographic changes.

[14], [15], [16], [17], [18], [19],

Criteria for the stabilization of a patient with community-acquired pneumonia

• body temperature <37.8 ° C,
• pulse <100 per minute,
• CHDD <24 per minute,
• systolic blood pressure> 90 mm Hg,
• SaO ₂ > 90% or Pa02> 90 mm Hg,
• ability to receive liquid and food per os,
• normal mental status

With the stabilization of the clinical state, it is possible to switch from intravenous to oral antimicrobial drugs. This approach is defined as "stepwise" therapy if the same antibiotic is used, or as "sequential" therapy if one intravenous antibiotic is replaced with another oral drug. The use of stepwise or sequential therapy can significantly reduce the cost of treatment and shorten the length of stay of patients in the hospital. Oral antibiotic with sequential therapy should have high bioavailability.

The duration of antibiotic therapy for severe community-acquired pneumonia is usually not less than 10 days. For pneumonia caused by intracellular pathogens, for example Legionella spp, treatment should be continued for at least 14 days. In addition, a longer duration of antimicrobial therapy (14-21 days) is recommended in patients with AE caused by S aureus and Gram-negative bacteria.

[20], [21], [22], [23], [24], [25], [26], [27]

Treatment of systemic disorders

Antibacterial drugs are the basis of therapy for patients with pneumonia, however, in the situation of management of patients with severe pneumonia, treatment aimed at preventing complications of pneumonia (respiratory failure, septic shock, etc.) is of great importance.

With moderate hypoxemia (S O ₂ 80-89%), provided that the patient's sufficient respiratory effort, preserved consciousness and fast reverse dynamics of the infectious process, correction of hypoxemia by inhalation of oxygen is possible with a simple nasal mask (FiO ₂ 45-50%) or a mask with a saccule (FI02 75-90%).

Indications and approaches to mechanical ventilation in severe community-acquired pneumonia without significant asymmetry between the lungs do not significantly differ from the tactics of management of patients with ARDS.

Alternative to traditional respiratory support - NVL with facial masks. According to one of the studies, NVL can improve gas exchange in 75% of patients and avoid intubation of the trachea in 60% of patients with community-acquired pneumonia. A good positive effect of NVL is achieved in patients with COPD who are suffering from severe community-acquired pneumonia. The need for using NVP in patients with other concomitant pathologies is controversial. The principles of non-invasive ventilation are the same as in all other situations.

Indications for non-invasive pulmonary ventilation in severe community-acquired pneumonia:

• pronounced dyspnea at rest, CRP> 30 per minute,
• PaO ₂ / FiO ₂ <250 mm Hg,
• PaCO ₂ > 50 mm Hg or pH <7,3.

The use of NVP in severe community-acquired pneumonia is justified in patients with background COPD disease, provided that the airway is well drained and at early stages of development of ODN.

Particular difficulty is represented by the problem of conducting a ventilation aid to patients with ODN against a background of unilateral (asymmetric) lung injury. Several approaches have been proposed to improve oxygenation in a patient with unilateral pneumonia:

• use of pharmacological drugs (almitrin, inhaled nitric oxide),
• periodic giving the patient a position on a healthy side,
• separate ventilation of the lungs, taking into account the different compliance and the different needs of PEEP in a healthy and "sick" lung.

Indications for independent (separate) ventilation:

• hypoxemia, refractory to high FiO ₂ and PEEP,
• PEP-induced deterioration of oxygenation and an increase in the fraction of shunt blood flow,
• hyperinflation of the unaffected lung and development of collapse of the affected lung,
• significant deterioration of hemodynamics in response to the use of PEEP.

This type of ventilation allow selective use of PEEP only in the affected lung, thus reducing the risk of developing barotrauma and hemodynamic disorders. When performing independent ventilation, intubation tubes with two channels and two inflatable cuffs are used.

In patients with severe sepsis and septic shock, solutions for filling the volume of circulating fluid (more often colloids) are prescribed in the first stage of therapy. In some cases, the administration of solutions may be sufficient to correct circulatory disorders. When they are ineffective, prescribe vasopressors. The effectiveness of glucocorticoids in severe community-acquired pneumonia has not yet been proven. With "refractory" septic shock, when suspected of adrenal insufficiency (patients with a previous intake of glucocorticoids), it is possible to use low doses of glucocorticoids (hydrocortisone 100 mg 3 times a day for 5-10 days).

To the new recommendations for the treatment of severe patients with community-acquired pneumonia with septic shock include the use of activated protein C-drotrekogin alfa. The drug is recommended for patients with septic shock with a total score on the APACHE II scale greater than 25. The greatest decrease in mortality with the use of drtrekogin alpha is noted in patients with severe VP caused by S. Pneumoniae. In addition to the severity of the patient according to APACHE II, an adequate indication for the administration of drtrekogin alpha in patients with severe community-acquired pneumonia and septic shock is the presence of a deficiency of at least two organ systems.

Prophylactic therapy with low-molecular heparins (enoxaparin sodium 40 mg / day or calcium supraparin 0.4-0.6 ml / day) in patients with ODN reduces the incidence of thromboembolism from 15 to 5.5% and prevents thromboembolic complications

With community-acquired pneumonia, the use of such drugs as nystatin, NSAIDs, antihistamines is not indicated.

What is the prognosis for severe community-acquired pneumonia?

Mortality of patients with severe community-acquired pneumonia hospitalized in the ICU is high (22-54%). In prospective studies on the prognosis of patients with severe community-acquired pneumonia, the main parameters associated with an unfavorable prognosis were:

• age over 70 years,
• carrying out mechanical ventilation,
• bilateral pneumonia localization,
• bacteremia,
• sepsis,
• the need for inotropic support,
• ineffectiveness of starting antibiotic therapy,
• infection of P. Aeruginosa.

The validated indices of PSI, CURB-65 and CRB-65 became a good tool for predicting the course of community-acquired pneumonia. In addition, some simple algorithms also make it possible to identify patients with severe community-acquired pneumonia, with an increased risk of death, for example, the presence of two of the three parameters (heart rate> 90 per minute, BP _syst <80 mm Hg, and LDH> 260 IU / L) increases the risk of death of patients six times compared with patients without these symptoms.

The causative factor also influences the prognosis of the mortality of patients is significantly increased when detecting such microorganisms as S. Pneumoniae, Legionella spp., Klebsiella pneumoniae, P. Aeruginosa.