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CMV - what is it? CMV: symptoms, treatment, photos. CMV infection - what it is, symptoms and treatment methods

Viruses do not detect themselves when they enter the body, which is caused by the stability of the immune system. As soon as a person gets sick or feels the approach of seasonal vitamin deficiency, hidden threats immediately undermine their once impeccable health and cause complications. Cytomegalovirus, a relative of herpes, is especially dangerous.

Cytomegalovirus virus

This is a viable infection that equally penetrates into children and adults, long time matures asymptomatically. Without harmful influence pathogenic factors can prevail for many years in the stage of rest, remission. Cytomegalovirus infection joins the herpesvirus family; it can be diagnosed in a patient’s biofluid laboratory.

Even in the absence of symptoms, the virus carrier is dangerous to others, as it can infect an incurable disease. If you are interested in what cytomegalovirus is, you can always get more detailed information from your local physician. When in medical card a code with ICD-10 symbols is indicated, its interpretation is as follows: cytomegalovirus infection in a patient.

How is cytomegalovirus transmitted?

A person became the carrier of a pathogenic infection. Since the pest is contained in high concentrations in biological fluids, such samples become the main carrier of pathogenic flora. The answer to the question of how people become infected with cytomegalovirus is obvious - through a kiss, during sexual contact, when sneezing and talking with an interlocutor. Also, one should not exclude the risk of infection during blood transfusion, the transfer of infection to the fetus from the biological mother.

Symptoms

There are known diagnoses that cannot be overcome modern medicine. Along with the herpes virus and HIV, it is impossible to eradicate cytomegalovirus forever - what it is is already clear. A microscopic infection enters the blood and causes the body’s immune response in the form of protein antibodies – lgg and lgm. As a result, the immune response is suppressed and harmful flora develops. If a cytomegalovirus infection rapidly develops in the systemic bloodstream, the symptoms in the body are as follows:

fever;
muscle weakness;
a sharp decline in performance;
inflammation and pain of the lymph nodes;
problems with hearing, vision, coordination of movement (in the severe stage).

It is important to note that with the latent form of the disease, alarming symptoms do not bother you, and the patient is not even aware of the spread of a deadly infection in the body. Once you get sick, we are talking about chronic or inflammatory ailments not related to the immune system; how it becomes obvious what CMV is, how the disease behaves in the body, what it threatens.

Among women

It is already known what infection causes the disease, but it is important to add that during pregnancy, representatives of the fairer sex, against the background of non-productive immunity, are at risk. Otherwise, the symptoms of cytomegalovirus in women are similar to the symptoms of the disease in the male body. You can note the presence of common symptoms of influenza. This:

body temperature 37 degrees;
body aches;
joint pain;
muscle weakness.

These are typical for acute stage symptoms of the disease that subsequently disappear. Cytomegalovirus becomes chronic, prone to relapses, mainly when the immune system is weakened. For an infected young lady, this is a particularly dangerous disease, since the planned pregnancy will not occur or will end in miscarriage.

During pregnancy

During intrauterine development, the body of the expectant mother is weakened, which is favorable conditions for infection and the subsequent spread of pathogenic infection. Cytomegalovirus in pregnant women poses a serious threat to mother and child, and the clinical outcome can be the most unpredictable. Complications for the health of a woman in an “interesting position” may be as follows:

The consequences for the child, starting in the prenatal period, are as follows:

congenital deafness;
heart disease;
hydrocephalus;
eye and dental diseases;
mental development disorder.

Cytomegalovirus in newborns

If the mother becomes infected with an incurable infection while pregnant, the baby is born with cytomegalovirus. When a pregnant woman was already a carrier of the virus at the time of conception, the baby can be born healthy. If congenital cytomegalovirus is detected, the microbe turns a new person into a disabled person from the first days of life. Doctors strongly recommend approaching pregnancy planning with special responsibility.

In men

The disease can also appear in the male body, while for a long time it is disguised as the classic symptoms of ARVI, affecting physical activity, causes loss of strength. Genital cytomegalovirus is an asymptomatic disease, but when the immune system is weakened, the signs of the disease have the following classification in the body:

Main symptoms. This is a general intoxication of the body with acute malaise and a violation of low-grade body temperature.
Minor symptoms. Pathologies of the genitourinary area, when the pathological process spreads to the urethra.
Clinical symptoms. Skin rash, swollen lymph nodes, nasal congestion, systematic migraine attacks, general weakness of the body.

Cytomegalovirus - diagnosis

The patient may have heard a lot about what a cytomegalovirus infection is, but it is difficult for him to imagine how to accurately diagnose this disease. Medical workers will take over the work and recommend a comprehensive examination based on studying the concentration and composition of biological fluids of the body. Required following procedures:

serological examination to determine the avidity of the pathogenic infection;
cytological analysis tissues to determine the degree of damage to cellular structures;
ELISA for simple and quick determination of antibodies in the blood;
light microscopy to determine the extent of tissue and cell damage;
DNA diagnostics for cellular modifications;
PCR to find out where the pathogenic infection came from;
general analysis urine to determine additional pathological processes body.

Blood test

Laboratory studies help to study not only the concentration of infection in biological fluid, but also the stage of its development. For example, in a serological study, cytomegalovirus indicators determine the activity of a characteristic disease. Alternatively, a jump in immunoglobulin M characterizes the relapse stage, and an excess of the norm in immunoglobulin G is more suitable for a period of remission of this disease.

How to treat cytomegalovirus

No matter what the doctors did, what therapeutic measures they did not carry out, they were unable to achieve a complete recovery of the clinical patient. Treatment of cytomegalovirus infection is aimed at strengthening the immune system, preventive actions and reducing the number of relapses of the underlying disease. Doctors know what CMV is, but they don’t even know how to cure it. The approach to the problem is comprehensive and involves taking the following medications:

Antiviral drugs: Panavir, Ganciclovir, Forscanet.
Interferons: Viferon, Cycloferon, Leukinferon.
Immunoglobulins: Megalotect, Cytotect.
Symptomatic treatment: according to medical indications.

In children

If a child is sick, the choice of intensive care depends on his age category. Children under 6 years of age can only eliminate cold symptoms using conservative methods, and older children can take antiviral drugs to reduce the activity of a dangerous infection. In the latter case, it is important to recall that such medications have a toxic effect and have side effects. Before treating cytomegalovirus with medication, you need to consult with your local pediatrician.

Is cytomegalovirus dangerous?

A carrier of a dangerous infection can infect people with whom he comes into contact to varying degrees. He does not need treatment if his immunity is strong. However, over time, the immune response noticeably weakens, and cytomegalovirus gradually destroys internal organs. The nervous system suffers. When asked by a patient whether cytomegalovirus is dangerous, doctors always answer in the affirmative, and it does not matter whether the victim is an adult or a child.

Prevention

Compliance with the rules of personal hygiene has great importance to prevent the activity of a pathogenic infection in the body.
Timely treatment of viral and colds, preventive measures.
When cytomegalovirus manifests itself, it is necessary to immediately be examined, find out and eliminate the cause of the pathology, and determine a treatment regimen.
If the smear is positive, the patient will have to undergo long-term treatment.
The best prevention cytomegalovirus – timely strengthening of the immune system using medicinal and natural methods.

Video

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Mode

(Control Mecanical Ventilation) - controlled artificial ventilation.

The essence of this mode is that while inhaling

breathing gas pressure is created in the internal circuit of the apparatus,

exceeding ambient pressure, and under the influence

The pressure difference causes the gas to be injected into the patient's lungs. Upon reaching

Below the set value of the tidal volume of gas in the device circuit, a switch occurs from the inhalation to exhalation phase, at which the pressure in the device circuit, and therefore in the patient’s lungs, freely drops to atmospheric level.

In this mode, the specified values are:

tidal volume;

breathing rate;

ratio of inhalation and exhalation time.

The specified values are set on the device by the doctor, depending

depending on the patient's condition.

The mode is used when the patient is unable

maintain your own breathing.

Mode CMV+S (Control Mecanical Ventilation +Sign) - controlled artificial ventilation lungs with periodic inflation of the lungs.

CMV+S is a sub-mode of the classic mode

CMV and differs from it in that the device periodically produces double the inhalation volume to inflate the lungs.

SIMV (Synchronizet Intermittent Mandatory Ventilation) mode - synchronized intermittent forced ventilation.

The essence of this mode is that when restoring

the patient can breathe spontaneously on his own

breathe through the breathing circuit of the device, however, to maintain

periodically reducing the guaranteed ventilation volume of the device

is turned on to carry out one "forced" cycle after

several cycles of spontaneous breathing. Specified synchro cycles

aligned in time with the patient’s breaths using the trigger block of the device.

The frequency of such inclusions is determined by the operator by setting the tidal volume, inhalation and exhalation times.

This mode allows you to train your breathing muscles

patient.

A+CMV mode

(Assistant Control Mecanical Ventilation) - (trigger mode) auxiliary controlled artificial ventilation.

This mode is carried out using a trigger device

a device designed to switch the distribution device of the device to inhalation due to the respiratory effort of the patient

enta. When carrying out the trigger method of artificial ventilation, you should remember to regulate one more parameter - the waiting time for a breathing attempt.

Adjustment of this value is included in the trigger device for

in order to ensure the transition to a controlled "forced"

ventilation mode after a certain period of time after

after the patient stopped breathing spontaneously. This measure, which is extremely important for patients in a severe unconscious state, is of no importance for patients with a more or less satisfactory condition and preserved consciousness. In such patients during sessions.

artificial ventilation, the waiting time for the attempt should

be set to a sufficiently large value.

PEEP (Positive and Expiratory Pressure) mode - ventilation with positive pressure at the end of expiration.

This is a method of ventilation with active inhalation and passive exhalation, in which the patient’s lungs during exhalation are not emptied to a functional residual capacity, but are under a certain residual positive pressure, which is set by the operator.

A number of studies have shown that artificial ventilation has reduced

In this method, by increasing the functional residual capacity of the lungs, it reduces the effect of premature closure of the airways, maintains the patency of the airways, and prevents the confluence of the alveoli. However, PEEP is undesirable in chronic airway obstruction, in which weakened

What is cytomegalovirus infection?

A characteristic feature of CMV is its complex structure and morphological properties. The main feature is the large DNA gene. The pathogen is characterized by slow reproduction, high resistance, and the ability to suppress cellular immunity. CMV infection affects all people, regardless of gender, age, or social status. Infection is transmitted from a carrier to a healthy person in several stages:

Entry of the causative agent of herpetic CMV infection into the body.
Spread of viral particles on the surface of the salivary glands.
Inside the cells, the virus begins active replication and enters the blood.
Reproduced in blood lymphocytes and macrophages of the immune system.
The spread of CMV causes secondary immunodeficiency states.

Once infected, CMV viral particles cannot be eliminated from the body. A person develops IgG antibodies against the virus. If you consult a doctor in a timely manner, it is possible to maintain the latent (dormant) state of the virus. Strong immunity protects a person, but with a decrease in immune activity, the virus provokes the development of concomitant diseases - hepatitis, pancreatitis, pneumonia. Cytomegalovirus and Epstein-Barr infection (mononucleosis) occur together, and health complications can occur in infected children. The insidiousness of the pathogen is that the cytomegalovirus itself is not dangerous to humans, but its destruction of immune cells causes immunodeficiency states, serious illnesses, and complications.

Forms of cytomegaly

Viral infection, similar to herpes, in which pathogenic cells with a DNA chain infect healthy cells of the body, disrupting their internal structure through gene replication, is called cytomegaly. The disease is accompanied by the formation of giant cytomegal cells, significantly increased in size. Several forms of the disease are classified: congenital and acquired cytomegaly of acute and chronic type according to symptoms, pathogenesis, and manifestations.

Congenital cytomegaly

For pediatrics actual problem is a congenital form of CMV that occurs when a child is infected in utero. The disease is characterized by multiple defects, damage to internal organs, and in some cases is asymptomatic. With pronounced clinical picture The child may be diagnosed with damage to the brain, liver, pathologies of the organs of vision and hearing.

Primary CMV during pregnancy causes congenital cytomegaly in 30-50% of children, when the virus is transmitted from mother to child through the placental barrier. When a pregnant woman is diagnosed with secondary infection, the virus is rarely transmitted to the newborn. The danger of the disease is enhanced by delayed manifestations of cytomegaly. Signs and consequences of the congenital form of the disease:

In the early stages, fetal death or severe congenital deformities are likely.
In the later stages, there are no developmental defects, but diseases arise.
The main symptom of the congenital form of CMV is brain damage.
Many women have babies born prematurely and with low birth weight.
Additional sign of CMV – hemorrhagic syndrome with a rash on the body.
Infection occurs with hemorrhages under the skin and mucous membranes.
Malformations: abnormal structure of the kidneys, damage to the lungs, esophagus, hepatitis, cirrhosis of the liver, jaundice, anemia, pneumonia, colitis, enteritis.

The course of congenital cytomegaly in children is characterized by delayed psychomotor development (speech, movement, perception), frequent colds, chronic diseases. If intrauterine infection occurs acutely with the addition co-infections, not excluded death after birth. Infection of the mother can greatly affect the health of the pregnant child, therefore prenatal (prenatal) diagnosis and mandatory blood sampling in newborns if CMV is suspected are important.

Acquired cytomegaly in newborns

This form of the disease is less dangerous than intrauterine infection. In most cases it is asymptomatic. The disease develops after birth and in the first weeks of life. The main symptoms appear after one to two months in the form of developmental delay, decreased or increased motor activity, seizures, visual impairment, hearing impairment, subcutaneous hemorrhages, rash.

Cytomegalovirus in children can be complicated chronic hepatitis, pneumonia, diabetes, pancreatitis. The asymptomatic course often turns into a latent form. Acquired infection does not give severe complications, if the development of CMV is controlled, increasing the child’s immunity.

Mononucleosis-like syndrome

A common form of cytomegalovirus infection is mononucleosis-like syndrome after a child emerges from the neonatal period. Clinical signs are similar to Epstein-Barr virus infection. Characteristics:

The duration of the incubation period is 20-60 days.
The symptoms are indistinguishable from the flu.
Prolonged fever with chills, temperature 38-39°C.
Fatigue, pain in muscles and joints, malaise.
Skin rash, swollen lymph nodes.
Sore throat, headache, less often – pneumonia.

The duration of the disease is from two weeks to two months. If there is no suspicion of pneumonia, hospitalization and special treatment are not required. It is enough to use drugs that relieve symptoms, antipyretics.

Cytomegalovirus infection in immunocompromised individuals

A decrease in the effectiveness of the protective function is observed in adult patients with chronic diseases. Manifestations of CMV infection begin with malaise, loss of appetite, general weakness, and fever. An unsatisfactory state of immunity creates favorable conditions for the spread of the virus. Risk group:

patients after internal organ transplantation;
AIDS patients, HIV-infected patients;
newborns with intrauterine infection.

For the growth and reproduction of CMV, ideal conditions are provided when it enters the body of a person with a weakened immune system. As cytomegalovirus infection progresses, chronic diseases worsen.

Why is cytomegalovirus dangerous?

Acquired infection occurs in the form of mononucleosis-like syndrome. Clinical manifestations are difficult to distinguish from infectious mononucleosis caused by other viruses. Primary infection may be asymptomatic; with secondary activation of the pathogen in healthy people and patients with weakened immune systems, complications may occur:

Lung diseases – segmental pneumonia, pleurisy (edema).
Liver diseases – hepatitis, elevated enzyme levels.
Intestinal infections - diarrhea, bloody stools, abdominal pain.
Inflammation of the brain, which can be complicated by severe neurological symptoms or lead to death.

CMV poses a serious threat to pregnant women. Intrauterine infection in the early stages can lead to fetal death, in the last months - to disorders nervous system, severe deformities.

Routes of transmission of cytomegalovirus

In the human body, CMV can be found in two forms - active and inactive. In a dormant (latent) state with strong immunity, the virus is harmless; when the protective functions are reduced, the mechanisms of the infected cell are activated and provoke concomitant diseases. A CMV carrier may be unaware of the infection and infect other people. Main routes of transmission:

Airborne - transmitted from person to person through saliva.
Sexual – infection is possible through prolonged sexual intercourse.
Transplacental – the possibility of infection of the fetus in the womb.
Hemotransfusion - during blood transfusion, during organ transplantation.

In addition, you can become infected with cytomegalovirus by using personal hygiene products that belong to the carrier. The pathogen is activated by frequent stress, hypothermia, and immunodeficiency states. An infectious disease in the absence of proper treatment develops into a dangerous generalized form.

Mechanism of development of cytomegaly

Cytomegaloviruses infect only humans, choosing their body as a host. The mechanism of development of CMV infection depends on the method of infection, genetic predisposition, primary or secondary infection, and the state of the immune system. Features of the lesion:

after entering the body, the virus invades cells;
an immune response is noted - the onset of inflammatory processes;
damage to internal organs and tissues occurs;
giant cytomegal cells with infiltrate are formed;
There is a general toxic effect and dysfunction of organs.

The infection can occur as a localized or generalized type. Local concentration of cytomegal is found in the parotid, maxillary, submandibular salivary glands with inflammation of surrounding tissues caused by immune reaction body. With a generalized type of infection, changes affect all organs.

Symptoms of infection

Signs of infection of the body with cytomegalovirus infection are similar to the symptoms of acute respiratory viral infection, so diagnosing the disease is difficult. When carrying CMV, patients with strong immunity do not show symptoms. Activation of pathogen cells causes general weakness, malaise, loss of appetite, weight loss, swollen lymph nodes, sore throat. Patients may be mistakenly diagnosed with ARVI. Immunity restoration leads to self-healing; the body produces IgG antibodies against CMV.

Among women

The female body reacts to cytomegalovirus with symptoms of ordinary flu with a slight increase in body temperature. Cytomegalovirus is considered dangerous during pregnancy. What matters is the period of gestation, primary or secondary infection. In the absence of IgG antibodies, the development of cytomegalovirus in a pregnant woman increases the risk of infection of the fetus through the placenta. Symptoms of CMV infection in women during pregnancy:

enlargement and inflammation of the lymph nodes;
muscle pain (myalgia) and general malaise;
slight increase in temperature, sore throat.

Cytomegalovirus during pregnancy has serious consequences for the fetus. The most dangerous effect of infection is when a woman is infected already in the process of bearing a child and there are no IgG antibodies against the pathogen. The virus easily penetrates the fetus, causing a threat of miscarriage; intrauterine death or the birth of a child with serious developmental abnormalities cannot be ruled out. When the temperature rises in women, the enlargement of the lymph nodes complements clinical manifestations CMVI.

In men

In the male body, CMV remains in a latent state for the time being. The activation of viral cells may be caused by stressful situation, cold, nervous tension. Symptoms of CMV infection in men are as follows:

Headache, chills, fever.
Swelling of the mucous membranes of the ENT organs.
Enlarged lymph nodes, runny nose.
Skin rash, inflammatory joint diseases.

Once infected, a man becomes a carrier of cytomegalovirus. Cases of damage to the genital organs have been reported during primary infection of men with CMV infection. Inflammatory processes in the testicles and genitourinary system are accompanied by painful urination. In the presence of cytomegalovirus in adults, symptoms appear brighter and more acute in patients with physiological immunodeficiency states and weakened body defenses.

In children

CMV infection of children can be congenital or acquired. Intrauterine infection of the fetus is possible if the pathogen is present in the male semen, through the placenta, membranes, and birth canals. A newborn can become infected while breastfeeding. CMV is more dangerous in children when the pathogen enters the fetus during pregnancy. If cytomegalovirus appears immediately in an infant, the symptoms are as follows:

Underdevelopment, dropsy of the brain.
Enlarged liver, jaundice, hepatitis.
Muscle weakness, cerebral palsy, epilepsy, heart disease.
Developmental delay, congenital deformities.
Deafness or gradual deterioration of hearing.

When the fetus is affected during development, CMV symptoms do not always appear immediately. Late signs of cytomegalovirus in a newborn are complemented by the following consequences and complications:

blindness and hearing loss;
mental retardation;
speech retardation;
psychomotor disorders.

In severe cases, infection of an infant with cytomegalovirus can be complicated by disturbances in the central nervous system, enlargement of the liver and spleen, jaundice, and a decrease in hemoglobin levels. Subject to change biochemical composition blood. Infants are characterized by a skin rash; in children under one year of age, cytomegalovirus causes disruption of the endocrine and digestive systems.

In preschool and school age, the pathogen is transmitted through saliva. Symptoms are the same as in adults. The latent course of the disease is widespread, which causes virtually no harm to the health of children. The body copes with the infection on its own, and the child becomes a passive carrier of CMV.

Testing for cytomegalovirus

Since CMV infection is difficult to distinguish from common colds by symptoms and signs, the doctor may prescribe additional diagnostics - tests to detect CMV DNA and IgG antibodies. It is necessary to study infection under the following conditions:

long course of the disease;
planned pregnancy;
clinical manifestations of mononucleosis without identifying the pathogen;
atypical course of pneumonia in children;
HIV infection.

The diagnosis is based on a PCR analysis for cytomegalovirus or an ELISA test for the detection of IgG and IgM class antibodies. The methods are recognized as the most effective and have low error. To obtain accurate results, you need to correctly collect material samples from the patient (any body secretion) and draw blood to detect IgG. In order to reliably confirm or exclude CMV infection, it is necessary to carry out several laboratory research.

Types of analyzes

Detection of CMV on early stages helps to timely choose treatment and means to enhance immunity. Some people suffer from cytomegalovirus asymptomatically; the body produces IgG antibodies against the pathogen. With reduced immunity, exacerbation of concomitant diseases and the development of cytomegaly are possible. For any type of analysis, blood, urine, feces, saliva, other secretions and body fluids are collected from patients, including scrapings and smears. genitourinary system. Main types of CMV diagnostics:

Polymerase chain reaction method - PCR for cytomegalovirus. The purpose of the analysis is to isolate DNA. If the answer is positive, CMV is diagnosed; if the answer is negative, there is no infection. Does not allow you to determine the degree of activity of viral particles.
Enzyme-linked immunosorbent assay (ELISA). When conducting the study, special titers of IgM and IgG are used. Their ratio in blood and serum makes it possible to determine the exact chemical composition. The IgG antibody class protects the body from viruses for a long time, the concentration of IgM increases immediately after the disease.
Immuno-chemiluminescence analysis of ICL. Diagnostics uses a reaction with phosphors that glow in UV light. Anti method CMV IgG IHLA is based on the study venous blood or patient urine. Anti CMV IgG reflects the presence of specific immunoglobulins that protect against CMV.
RIF analysis for cytomegalovirus is a method of indirect immunofluorescence. The presence of the PP65 indicator in the blood is determined, which characterizes the protein membrane in leukocytes. The avidity index, which characterizes the relationship between IgG antibodies and antigens, is taken into account.

Viruses can be detected by sowing - biological material is placed on a nutrient medium, and a pure Cytomegalovirus culture containing deoxyribonucleic acid (DNA) macromolecules is grown. The method is time-consuming, so detection of IgG and IgM immunoglobulins by ELISA is more often used.

Preparing to submit material

The most informative material for molecular laboratory studies for CMV infection is blood, but the affected cells are constantly present in it only in the stage of viremia (viruses enter the bloodstream). Therefore, to stage accurate diagnosis It is recommended to conduct several tests with different biological material from patients. Preparation for collecting samples for a blood test for cytomegalovirus:

Blood donation for IgG testing is performed only on an empty stomach.
You cannot drink alcohol, smoke, or eat 12 hours before the test.
If venous blood samples are taken, the patient needs to rest for 15 minutes.
Do not take medications or the laboratory should be notified.
Before drawing blood for analysis for antibodies to cytomegalovirus, it is necessary to limit physical activity.
Children under five years of age should be given plenty of boiled water to drink before donating blood for IgG detection.

When preparing for a PRC analysis to detect viral DNA, patients should not have sex three days before the tests. Before donating material (feces, urine, semen, vaginal secretions, saliva), it is prohibited to use antibacterial hygiene products. Samples are not taken from women a couple of days before menstruation or within two days after the end of bleeding. Immediately before sampling, the patient should not visit the toilet 3 hours before donating the material. These measures are necessary to ensure that samples for IgG analysis, cytomegalovirus DNA, culture, and ICLAI IgG are taken correctly, which eliminates false research data.

How to understand the results

After conducting the research, the next stage of diagnosis is deciphering the analysis for cytomegalovirus. The detected antibodies, their quantity and characteristics are recorded on the medical form. What the information received shows:

Anti IgG CMV (-) and IgM (-) values – there was no contact with a CMV carrier.
IgM is positive in the presence of negative IgG – activation of the virus.
IgG positive, IgM negative – the risk of infection is minimal.
IgG (+), IgM (+) – presence pathogenic microorganisms CMV with exacerbation.
The anti IgM CMV indicator (-) with IgG (+) and a high avidity index (AI more than 42%) – the patient suffered an infection more than six months ago.
If IgM (-), IgG (+), and AI is less than 41%, it is necessary to repeat the analysis; an error in the results is possible.
When IgM (+), IgG (-), and AI is less than 31%, the disease is actively developing, with IA up to 41% - the recovery stage, AI more than 42% - residual phenomenon after illness.

The number of antibodies is subject to diagnosis at a titer of one to one hundred. The use of reagents with different degrees of sensitivity in laboratory conditions leads to differences in the interpretation of results. The accuracy and reliability of data is especially important when testing pregnant women, since CMV infection poses a threat to the fetus. If IgG positive during pregnancy, and the IgM antibody level is negative, the fetus is not in danger, IgG antibodies reliably protect it in the womb from CMV. If cytomegalovirus DNA is detected in the first trimester, the woman may be advised to terminate the pregnancy in the event of primary infection. The presence of IgG immunoglobulins indicates that the expectant mother has already had CMV and the body has developed antibodies against the disease, which is safe for the fetus and mother.

When the results of patient blood tests are deciphered, the number of detected antibodies, individual for all people, is additionally taken into account. Each laboratory that conducts ELISA blood tests has its own standards for the content of immunoglobulins in diluted serum (the standard ratio is 1:100). The normal values must be indicated on the form of the diagnostic laboratory - these are reference values. A result is considered negative if the number of IgG antibodies is less than the minimum limit value, and a positive result will be if the number of antibodies is greater than the maximum limit value. Additional information on test interpretation:

An increased titer of IgG and IgM four times per week is the development of the disease.
If Anti CMV IgG is elevated and IgM is not detected, the body has encountered the virus.
When Anti CMV IgM is higher than normal, IgG is detected or not - an active process.
If IgG antibodies to cytomegalovirus showed positive result and the amount of IgM increased - secondary infection.

Laboratory forms must indicate the reference values with which the results are compared. The values are given in arbitrary units, optical density indicators, in the form of titers, optical units, and the number of units per milliliter. The Anti CMV IgG result, which goes beyond the reference values, is an indirect sign of the activity of viral cells. In this case, attention is paid to the presence of antibodies IgM class and avidity index. How to read a blood test for IgG antibodies:

What does IgG antibodies to cytomegalovirus greater than 250 mean? Such results may indicate that the patient was infected about 3 months ago.
IgG to cytomegalovirus is more than 250 in the presence of IgM class antibodies - primary infection when IA is less than 50%, chronic - when IA is more than 60%.
If IgG antibodies are detected above 140, but IgM are not detected, the patient suffered from the disease about six months ago.
When Cytomegalovirus IgG is positive in the data obtained, quantitatively this means that the number of antibodies is higher than the accepted norm.

Experts must decipher the test results based on reference values. Antibody levels are individual for each person and depend on the body’s ability to synthesize immunoglobulins.

An effective way to detect cytomegalovirus DNA is to perform a PCR test, which uses semen, a vaginal swab, saliva, or other fluids or secretions. Cytomegalovirus analysis quality. DNA is considered a reliable, fast and reliable way to detect infection. If cytomegalovirus is detected in a smear in a pregnant woman, the gynecologist may prescribe a blood test to determine the presence or absence of IgG and IgM antibodies.

What is avidity

In the test results of patients, an indicator such as the avidity index is taken into account. The value characterizes the strength of the bonds between antigens and IgG, IgM antibodies and the ability of immune defense cells to bind to viral particles, as well as suppress their activity during infectious infection. The use of the avidity index for the diagnosis of CMV is differential in nature; the results are interpreted taking into account the number of IgG, IgM:

When antibody avidity is below 50%, primary infection is diagnosed.
If the IgG avidity index for cytomegalovirus is above 60%, you are a carrier or chronic form of CMV.
AI at the level of 50-60% - a repeat study is required.

The body is not infected with cytomegalovirus if avidity is zero, that is, no antibodies are detected. With carriage, latent infection, primary or secondary infection, the number of IgG antibodies and their ability to bind antigens increases. When interpreting the tests, all results are taken into account - the number of standard units of IgG and IgM in the blood serum, the increase in titer during repeated analysis, the avidity index, the indicator of excess of reference values.

How to treat cytomegalovirus

In modern medicine there is no universal way to completely cure cytomegalovirus. After infection, the viral cells remain in the body forever, and the person becomes a carrier of the disease. With a strong immune response, treatment is not required - the antibodies produced protect the patient from developing infection. If the immune system is weak, the disease occurs with accompanying symptoms and changes the normal state of the body. Conservative therapy includes:

In case of mononucleosis-like form (signs of a cold), symptomatic drugs are prescribed.
Adult patients with low immunity if the infection is actively developing, Ganciclovir, Panavir, Cidofovir, Foscarnet are prescribed.
To suppress the activity of viral cells and restore affected tissues and organs, immunoglobulins Cytotect, Megalotect, Neocytotect are prescribed.
To restore and strengthen the immune function of the body, patients are prescribed immunomodulators Viferon, Genferon, Leukinferon.
To treat cytomegalovirus in children, the same drugs are used as for adults, but in a reduced dosage, and drugs that relieve the symptoms of the disease.
Pregnant women are prescribed Cytotect for acute form diseases and Viferon, if viral cells are found in the cervix.

To prevent cytomegalovirus, patients are prescribed B vitamins and mineral complexes. Depending on which organs the infection is localized in, patients should know which doctor treats cytomegalovirus. A neonatologist and pediatrician will help with illnesses in children. In case of damage to the organs of vision and hearing - an ophthalmologist, ENT doctor. Pregnant women are prescribed therapy by a gynecologist; patients with reduced immunity are observed by a pulmonologist or immunologist.

Treatment of cytomegalovirus with folk remedies includes taking compounds that strengthen the immune system:

Teas made from raspberry and currant leaves with honey give strength to the body.
Decoctions from mixtures of wild rosemary, string, birch buds, thyme, yarrow.
Medicinal decoctions of alder, licorice, chamomile, leuzea, string.
An infusion of the roots of calamus, bergenia, peony, elecampane, licorice, and rowan fruits.
Including fresh onions and garlic in your diet reduces the risk of CMV infection.

Infusions of medicinal herbs and mixtures for children are prepared from half the portion of raw materials recommended for adult patients.

For preventive purposes, tea tree oil can be sprayed in a sick patient's room. To reduce the likelihood of viral cells transitioning from a latent (sleeping) state to the active phase, it is recommended to strengthen the immune system by everyone accessible ways. Cytomegalovirus affects people of any gender and age, remaining forever in the body. If the immune system is strong, the viral cells sleep and do not harm human health. Therefore, it is important to strengthen the immune system, eat right, exercise, and women should get tested for IgG before planning pregnancy.

Recently, it has become fashionable to be examined for herpes infections, which include cytomegalovirus (CMV) - type 5 herpes viruses. Doctors of almost all specialties prescribe tests for CMV, and then treat something for a long time and persistently. What and why? If you feel weak, depressive state, you notice a long and persistent increase in body temperature to subfebrile levels (37.0-37.4 ° C), you have cystitis, erosion, vaginitis, colpitis, dysplasia were discovered, you cannot get pregnant, the pregnancy was terminated, a baby was born with a pathology, and then he endlessly suffers from ARVI, bronchitis, be prepared that the doctor will prescribe an examination for herpetic infections, including CMV. So what kind of virus is this, is it so dangerous, is it really to blame for the development of all the above pathologies, how to identify it and how to treat it? Let's figure it out together and find answers to these and other questions.

What is cytomegalovirus?

As mentioned above, cytomegalovirus (CMV) is a member of the herpesvirus family, which includes herpes simplex viruses types 1 and 2, chickenpox and the Epstein-Bar virus (the causative agent of infectious mononucleosis). The virus received its name based on specific changes in the cells of the body (a significant increase in size - cytomegaly) after infection by this virus. After infection, the virus is found in various biological fluids of the human body: urine, saliva, breast milk, blood, tears, semen, vaginal discharge, etc. It is worth noting that once the virus enters the body, in most cases it remains there forever.

How does cytomegalovirus work?

Regardless of the method of infection, the virus enters the blood, spreads throughout the body and is initially fixed in the cells lining salivary glands, in which it finds favorable conditions for reproduction. Once in the blood of a healthy person, the virus causes a pronounced immune response - the body begins to produce specific antibodies. During primary infection with CMV, as with any other pathogen, intensive production of IgM is characteristic. Immunoglobulins M against cytomegalovirus are formed approximately 4-7 weeks after infection and remain in the blood for 16-20 weeks. Detection of them in the blood during these periods may be evidence of a primary cytomegalovirus infection. As the immune response develops, the IgM titer decreases, but there is a significant increase in the IgG titer. Subsequently, IgG, having reached a maximum, decreases, but, unlike IgM, IgG class antibodies to the structural proteins of CMV continue to remain in the blood in positive titers throughout life. Reactivation of the infection leads to an increase in IgG titer. In this case, there is also an increase in IgM titer, but it is not as significant as during primary infection.

Who and how can become infected with cytomegalovirus?

In childhood (up to 5–6 years), transmission of CMV from mother to child is possible (in utero, during childbirth, when caring for a newborn and breastfeeding), or as a result of contact with other infected children who secrete the virus (usually through saliva) . Even asymptomatic carriers are capable of transmitting the virus to uninfected individuals. Only transmission of the virus from mother to fetus occurs mainly only during an active infectious process. From the age of 16 to 30 years, transmission of the virus occurs through the saliva of a sick interlocutor, semen, discharge from the vagina and cervix, urine, blood, and tear fluid. However, the main route of transmission at this age is sexual intercourse. We should not forget about the possibility of infection during blood transfusion or organ transplantation of a patient with cytomegalovirus infection.

How widespread is cytomegalovirus infection?

CMV infection is widespread in the human population, so depending on the region and socio-cultural level, CMV infection affects from 50 to 100% of the adult population. At the same time, the infection rate of children who attend preschool institutions is 25-80%. TO reproductive age From 15 to 45% remain sensitive to CMV infection. According to statistics, every year from 2 to 6% of women are infected with CMV during pregnancy. Since infection often coincides with pregnancy, cytomegalovirus infection is considered the most common intrauterine infection (IUI) and one of the most common causes of miscarriage. As a result, 1 in 150 children is born with congenital cytomegalovirus infection. Approximately 1 in 750 children are born with diseases caused by cytomegalovirus.

How does cytomegalovirus infection manifest in children and adults?

Most healthy children and adults infected with CMV do not have any symptoms of infection and are not even aware that they are infected. And this is not surprising, since the clinical picture of CMV is not specific; the same symptoms can be observed in many diseases of an infectious nature. Agree that symptoms such as increased body temperature, fatigue, inflammatory processes in the nasopharynx and oropharynx, and enlarged palatine tonsils (tonsils) first of all make you think about a common cold or acute respiratory viral infection, but not about CMV. This is why you often cannot remember when the cytomegalovirus infection occurred. The most common form of CMV infection in children and adults with normal immunity is mononucleosis-like syndrome, which by clinical manifestations cannot be distinguished from infectious mononucleosis, which is caused by another herpes virus - the Ebstein-Barr virus. The period of primary infection lasts for 2-3 weeks, then the following occurs:

self-healing with a sufficient immune response (the body has produced antiviral antibodies);
transition to an inactive form - virus carriage (CMV positivity);
with insufficient immune response, transition to a localized form;
in the absence of an immune response, transition to a generalized form.

CMV positivity– this is the persistent detection of G antibodies to cytomegalovirus (90-95% of the adult population). In this case, the virus remains in the body of an infected person for years in a latent (dormant) state, while the virus carrier (in most cases) does not pose a danger to others. However, with a sharp decrease in immunity, carriage can develop into an active form of the disease. IN in rare cases observed

localized form with damage to the genitourinary system (in women it occurs acutely in the form of endocervicitis, endometritis, salpingo-oophoritis, in men CMV is asymptomatic or with symptoms of sluggish urethritis). And finally

generalized form of CMV occurs in persons with severe immunodeficiency (HIV infection, immunodeficiency due to chemotherapy, radiation sickness). With this form of CMV infection, inflammation of the liver tissue, adrenal glands, spleen, pancreas, kidneys, esophagus, lungs, damage to the blood vessels of the eye, intestinal walls, brain and peripheral nerves. There is an increase in the parotid and submandibular salivary glands, inflammation of the joints, and skin rash.

How does cytomegalovirus infection manifest in the fetus and newborn?

As mentioned above, the intrauterine form of CMV is typical for children whose mothers encountered CMV for the first time during pregnancy and suffered an infection caused by this virus. If the mother becomes infected and falls ill with CMV, during pregnancy the fetus receives CMV through the placenta. Congenital cytomegalovirus infection often leads to miscarriages, stillbirths and various birth defects. The mortality rate for congenital cytomegalovirus infection is 20-30%. Such consequences of CMV infection are especially characteristic in the first 20 weeks of pregnancy. Infection in more late dates pregnancy or reactivation of chronic CMV infection causes intrauterine lesions various organs and systems in the fetus (they are delayed in development, including mental development, have hearing loss, blindness). However, intrauterine infection of the fetus is not always the cause of congenital CMV; in most cases it is asymptomatic, and only in 5% of newborns leads to the development of the disease. During childbirth, the source of CMV can be an infected cervix. After childbirth, breastfeeding plays an important role in the transmission of infection. When infected with cytomegalovirus during childbirth (through the birth canal) or after birth (through breastfeeding or normal contact), in most cases the infection remains asymptomatic.

How to avoid infection with cytomegalovirus?

Prevention of cytomegalovirus infection should be carried out for women at risk. In preparation for pregnancy or directly during pregnancy, this group includes women with negative results for IgG and IgM for CMV (seronegative). After all, if a woman does not have antibodies to the virus, then her body is not yet familiar with this pathogen. Of course, given that the virus is widespread, the possibility of infection cannot be completely excluded. However, compliance is sufficient simple rules personal hygiene can somewhat reduce this probability. What are the rules?

Do not forget to wash your hands thoroughly, especially after visiting the street and public transport;
Avoid kissing on the lips, especially with children under 5 years of age;
Be sure to use separate dishes and cutlery;
Cosmetics should also be individual; don’t even think about using samples in stores;
If you work in a nursery, kindergarten, or school, take a vacation during pregnancy or sharply limit contact with children.

It may seem to you that it is impossible to accomplish all this... But the health of the unborn baby is much more important than all social conventions!

In addition to following hygiene rules, screening diagnostics of CMV infection and activity is necessary every 1.5-2 months of pregnancy.

How to diagnose cytomegalovirus infection?

Cytomegalovirus infection belongs to the list of those few infections, the diagnosis of which cannot be established only by the clinical picture. The diagnosis of CMV cannot be made without appropriate laboratory confirmation. Laboratory diagnostics cytomegalovirus infection includes:

cytological examination of saliva and urine sediments (detection of giant cells);
polymerase chain reaction (PCR), which is based on determining the DNA of the virus in the blood or in mucosal cells (scrapings, saliva, sputum, urine). It is recommended to perform a quantitative PCR reaction, which allows one to judge the degree of reproduction of the virus, and therefore the activity of the infectious process;
serological tests of blood serum (determination of cytomegalovirus-specific antibodies in the blood). Currently, the most accurate and sensitive method for determining antibodies is linked immunosorbent assay(ELISA), which provides the determination of both IgG, IgM, and IgG avidity to CMV.

Dynamics of laboratory parameters depending on the stage of CMV infection

Parameter	IgM	IgG	IgG avidity	DNA blood
Stage of infection (risk of transmission to fetus)	IgM	IgG	IgG avidity	DNA blood
Seronegativity, risk group (0)	(-)	(-)	do not define	(-)
Primary infection (5)	(+) Antibody titer rises, then falls or remains low	(-/+) IgG is absent, then appears and begins to increase	low	(+)
Late stage primary infection (4)	(+/-) Antibody titres are low or absent	(+) The titer increases, then reaches a constant level	average	(+)
Latent stage (1)	(-) IgM absent	(+) Antibody titer is high and does not change	high	(-)
Reactivation or superinfection stage (2-3)	(+/-)	(+)	low	(+)

In addition to specific laboratory data, it is necessary to take into account clinical manifestations, medical history and the results of other research methods (ultrasound, blood biochemistry, condition T cell immunity and etc.).

Who should be examined for CMV infection and how?

As mentioned above, women planning a pregnancy, as well as pregnant women, should be examined for CMV infection in order to identify a risk group (seronegative). To identify a risk group, the level of specific IgG in the blood serum is determined. At negative result the woman is at risk. If in the last 2 months a woman has had a fever, tenderness in the liver area, or a high IgG titer has been detected, then it is advisable to also determine the IgM level. If the IgM titer is positive, it is recommended to delay the date of conception by 2-3 months. All subjects who do not have a positive IgM titer may be recommended to conceive. During pregnancy, women at risk are recommended to determine the level of specific IgM to CMV once every 1.5-2 months.

If a pregnant woman has clinical signs of CMV infection and had specific IgG before pregnancy, it is sufficient to perform an ultrasound scan of the fetus, since the risk of developing acute cytomegalovirus infection in the fetus is minimal. If the pregnant woman was at risk or had not previously been examined for the presence of specific antibodies, it is necessary to determine the level of IgG and IgM, the avidity of IgG using the ELISA method, and also conduct blood, urine and saliva tests for CMV DNA using the PCR method.

Prenatal diagnosis of intrauterine CMV infection is possible using ultrasound, amniocentesis, and cordocentesis. Ultrasound can most often detect micro- and hydrocephalus, cystic changes or foci of calcification in the periventricular zone of the brain, liver tissue, placenta, fetal growth restriction, oligohydramnios, fetal ascites, pericardial or pleural effusion, hypoechoic bowel, hydrops fetalis. In the fetal blood, you can determine cytomegalovirus DNA (PCR), an increased level of specific IgM (ELISA), detect anemia and thrombocytopenia (complete blood count), hyperbilirubinemia and increased liver transaminases (biochemical blood test). If the test result is negative, but there is a high risk of infection to the mother, the test is repeated after 4-8 weeks.

If a newborn is suspected of having CMV, it is first necessary to conduct a PCR test of the newborn's biological fluids (saliva, urine) for CMV DNA. At the same time, it is necessary to determine the level of specific IgM to CMV in the blood serum using the ELISA method. The diagnosis of congenital CMV infection can be considered established if during the first two weeks of a child’s life it is possible to isolate the virus from urine, saliva or other biological material. After two weeks of life, positive PCR test results may reflect both congenital and perinatal infection.

How to treat patients with cytomegalovirus infection?

It is impossible to completely remove (eliminate) cytomegalovirus from the body. However, if you consult a doctor in a timely manner, necessary research and begin the necessary therapy, it will help increase the period of remission, keep the virus in a “dormant” state for many years and prevent it from reactivating. This will ensure normal pregnancy and birth. healthy child. What to do if you suspect primary CMV infection during pregnancy? Of course, first of all, get a full examination. Then, on the doctor’s recommendation, carry out the necessary therapy. However, at present there are no drugs or vaccines that can prevent intrauterine infection of the fetus with cytomegalovirus. There is evidence that the use of modern antiviral drugs may prevent hearing loss in children with congenital CMV. But they all have many side effects and a teratogenic effect on the fetus, and therefore should be prescribed only when life-threatening states. Perinatal diagnostic methods will come to the rescue, which will help find out whether the baby has become infected and whether the virus has had an impact on its development. There is no need to despair prematurely, because with primary infection with CMV during pregnancy, the probability of infecting the baby, although high, is not 100%.

Instead of an afterword

Let us briefly repeat the features of CMVI. CMV is a type 5 herpes virus, which can be infected through contact with biological fluids (saliva, urine, tear fluid, blood, semen, cervical and vaginal mucus) of a sick person, as well as in utero from a primary infected mother and during childbirth during through the birth canal of a woman with active CMV infection. After infection, a CMV infection develops, which most often goes unnoticed by humans, as it is often disguised as an acute respiratory infection. After past illness In most cases, the virus remains in the human body for life; it cannot be removed using currently existing drugs. Class G immunoglobulins also remain in the blood of an infected person for life, indicating familiarity with the virus, but not immunity to it. Fluctuations in the level of this immunoglobulin, especially taken separately, do not have independent significance and require additional studies (determination of IgM to CMV and avidity of IgG to CMV by ELISA, determination of CMV DNA in blood, urine and saliva by PCR). Only primary infection with cytomegalovirus during pregnancy is dangerous. So, according to statistics, during pregnancy, about 2-6% of women become infected with CMV. In 1 out of 150 births, a baby is born with congenital CMV, and in 1 out of 750 cases, the child develops a disease caused by cytomegalovirus. But with timely diagnosis, prevention and treatment, primary infection of a pregnant woman and intrauterine infection of a baby can be avoided. Thus, if you are planning a pregnancy, get diagnosed with CMV! This CMV test will help you assess how much caution is needed during pregnancy regarding CMV. If you have positive test for IgG, then you will know that there is a negligible chance of intrauterine cytomegalovirus infection. If the IgG test is negative, then you need to carefully follow the recommendations outlined in this article. Forewarned is forearmed! Feel free to get pregnant, carry it calmly, give birth easily and raise a healthy baby! Good luck to you!

"CMV", "Continuous mandatory ventilation"

The secret of the name:

The abbreviation “CMV” currently has four decoding options:

continuous mechanical ventilation.

continuous mandatory ventilation.

controlled mechanical ventilation.

controlled mandatory ventilation.

In all cases, the meaning is the same: “All breaths are forced.” In this case, the manufacturing companies used the name of the breath coordination method as the name of the ventilation mode.

Definition:

“CMV” is a ventilation mode in which all breaths are mandatory (mandatory) and performed at a given frequency. Control method by volume (volume controlled) or pressure (pressure controlled)

Description of CMV modes*:

*This is not a typo, several modes are hidden under the name “CMV”.

Other "CMV" mode names

"Control mode"
"Assist control" ("AC")
“Assist/control” (“A/C”)
"Assisted mechanical ventilation" ("AMV")
"Volume control" ("VC")
"Volume cycled assist control"
"Pressure control" ("PC")
"Time cycled assist control"
If you try, you can find more options.

What does the name say?

If the word "assist" or "assisted" is used, time-trigger + patient trigger is used.
If the word "volume" is used, the ventilator controls inspiration by volume.
If the word “pressure” is used, the ventilator controls inspiration based on pressure.

It is impossible to say more from the name of the regime.

What do these modes have in common? All inhalations are the same from the point of view of assessing the controlled parameters (inspiratory duration and inspiratory volume or pressure).
What is the difference between these modes? Firstly, in the method of inhalation control (Pressure controlled or Volume controlled), secondly, is there a patient trigger and if so, which one, thirdly, for Volume controlled there are two possible ways to switch to exhalation - by time (Time Cycling) or by volume (Volume Cycling). It turns out that four modes are hidden behind a large number of names.
Thus, saying: “Ventilation is carried out in CMV mode” is not enough; clarification is needed.
What to do? Pick up the manual (user manual) for your ventilator and set for sure what mode this mode has: Trigger, Control, Limit and Cycle.

Below we will show two ventilation modes, each of which has more than ten names. Please note that modes with different ways Inhalation controls can have the same names.

Example #1:

Variant of the ventilation mode with the PC-CMV (Pressure controlled continuous mandatory ventilation) pattern.

The first and second breaths are turned on “according to the schedule” - time-trigger. The third breath is included in response to the patient's breathing attempt (patient trigger). The first and second breaths are mandatory, the third breath is assisted. Please note: “mandatory” differs from “assisted” only in the trigger. The flow, pressure, volume and time of these breaths are the same. Switching from inhalation to exhalation by time (Time Cycling).

“Controlled mandatory ventilation” (“CMV”)
“Continuous mechanical ventilation” (“CMV”)
“Controlled mechanical ventilation” (“CMV”)
"Control mode"
"Continuous mandatory ventilation + assist"
"Assist control" ("AC")
“Assist/control” (“A/C”)
“Assist-control ventilation” (“ACV”) (“A-C”)
"Ventilation + patient trigger"
"Assist/control +pressure control"
"Pressure controlled ventilation" ("PCV")
"Pressure controlled ventilation + assist"
"Pressure control" ("PC")
"Pressure control assist control"
"Time cycled assist control"

There are probably other options.

Example #2:

Variant of the ventilation mode with the VC-CMV (Volume controlled continuous mandatory ventilation) pattern. In this example, switching to exhalation occurs by volume (Volume Cycling).

The first and second breaths are turned on “according to the schedule” - time-trigger. The third breath is included in response to the patient's breathing attempt (patient trigger). As in the first example, the first and second breaths are mandatory, the third breath is assisted. Please note: “mandatory” differs from “assisted” only in the trigger. The flow, pressure, volume and time of these breaths are the same.

Manufacturers give this mode the following names:

“Controlled mandatory ventilation” (“CMV”)
“Continuous mechanical ventilation” (“CMV”)
“Controlled mechanical ventilation” (“CMV”)
"Control mode"
"Continuous mandatory ventilation + assist"
"Assist control" ("AC")
“Assist/control” (“A/C”)
“Assist-control ventilation” (“ACV”) (“A-C”)
"Volume controlled ventilation" ("VCV")
"Volume control" ("VC")
"Volume control assist control"
"Volume cycled assist control" ("VC-CMV")
"Ventilation + patient trigger"
“Intermittent positive pressure ventilation” (“IPPV”)

Don't get your hopes up, there are probably more names for this mode.

The second example shows graphs of pressure and volume for VCV with constant flow. Those. the flow does not change during the entire inhalation time. For clarity, let's imagine how a piston moves in a cylinder at a constant speed. The flow graph in this case has the shape of a rectangle (square).

Example #3:

How does airway pressure depend on the shape of the flow curve?

Modern ventilators with a flow system more complex than a piston in a cylinder can provide volume-controlled ventilation with a decreasing flow curve shape. This flow curve shape is similar to the "PCV" flow curve. In English, this flow curve shape is called a “descending ramp flow waveform”. See how the pressure and volume curves change.

You can see that as a result of the change in the flow curve, the pressure and volume curves have changed. This version of VCV is actually flow control, but in the second part of the book we warned that since volume is the product of flow and inhalation time, methods of inhalation control by volume and flow are combined under the concept of VCV (volume control ventilation ). As a result of applying descending flow at the same tidal volume as Example #2, the peak airway pressure (PIP) is lower and the mean airway pressure (MAP) is higher. Please note that all curves have become similar to PCV (example no. 1). The fact that with this modification of VCV the initial flow value is greater than with a constant flow is not dangerous, since the maximum flow value occurs at the beginning of inspiration (“empty lungs”), and as the lungs fill, the flow decreases. This flow-volume ratio is completely physiological and does not lead to a dangerous increase in pressure in the respiratory tract.

Example #4:

“Intermittent positive pressure ventilation” (“IPPV”) and “Pressure limited ventilation”

The name “IPPV” is used by Dräger for the ventilation mode with the VC-CMV (Volume controlled - continuous mandatory ventilation) pattern and switching to exhalation by time (Time Cycling). The diagram presented to you corresponds to the diagrams from the instructions for the Evita series devices. The second breath in our diagram is no different from the first, only the explanations are translated into Russian.

The diagram shows that the pressure in the airways increases until the ventilator delivers tidal volume. Once the tidal volume has been delivered, the flow stops. Exhalation will begin only after the inhalation time (Tinsp) has ended. At this moment the exhalation valve opens. Thus, the inhalation time is divided into two segments - this is the flow time of inhalation and the inspiratory pause. This understanding of the two components of inspiratory time is important to understand how the Pmax or Pressure limit option works.

"Pressure limited ventilation" based on the “Intermittent positive pressure ventilation” (“IPPV”) mode

(This CMV option belongs to the group of Dual Control Within a Breath modes. The control principle is autosetpoint)

Let us remind you that the Volume control method of inhalation control ensures the delivery of the prescribed tidal volume. For a ventilator, tidal volume is the target. Airway pressure depends on resistance and compliance, and volume is the product of flow and time. The ventilator is tasked with delivering the tidal volume without exceeding the Pressure limit. The only solution is to reduce the flow and increase the flow inspiratory time. As a result, the inspiratory pause is shortened, but the inspiratory time does not change. The tidal volume does not change; in the diagram it is the area under the flow curve, S1=S2.