All numerous methods of X-ray examination are divided into general and special.
General methods include methods designed to study any anatomical regions and performed on general-purpose x-ray machines (fluoroscopy and radiography). Also, a number of methods should be attributed to the general ones, in which it is also possible to study any anatomical areas, but either special equipment is required (fluorography, radiography with direct image magnification), or additional devices for conventional x-ray machines (tomography, electroroentgenography). Sometimes these methods are also called private.
1. Fluoroscopy (X-ray transillumination) - a method of X-ray examination, in which an image of an object is obtained on a luminous (fluorescent) screen. On the side facing the doctor, the screen is covered with lead glass, which protects the doctor from direct exposure to x-rays. The fluorescent screen glows weakly, so fluoroscopy is performed in a darkened room.
Fluoroscopy is the simplest and most accessible diagnostic method. When roentgenoscopy of the chest, the structural features of the chest, its various deformations, which can affect the location of organs in the mediastinum, are carefully evaluated. When examining the lungs, attention is paid to the condition of the roots of the lungs, their pulsation, the structure of the shadow of the root is assessed, with an increase in it, the pulmonary pattern is studied, in particular, the correct branching of the vessels, their caliber, etc. (Appendix 1).
Radioscopy has many advantages. It is easy to implement, publicly available, economical. It can be performed in the X-ray room, in the dressing room, in the ward (using a mobile X-ray machine).
However, conventional fluoroscopy has its weaknesses. It is associated with a higher radiation exposure than radiography. It requires darkening of the office and careful dark adaptation of the doctor. After it, there is no document (snapshot) left that could be stored and would be suitable for re-consideration. But the most important thing is different: on the screen for transmission, small details of the image cannot be distinguished. Due to the high radiation exposure and low resolution, fluoroscopy is not allowed to be used for screening studies of healthy people.
2. Radiography - a method of X-ray examination, in which a static image of an object is obtained, fixed on any information carrier. Such carriers can be X-ray film, photographic film, digital detector, etc. An image of any anatomical region can be obtained on radiographs. Pictures of the entire anatomical region (head, chest, abdomen) are called overview (Appendix 2). Pictures with the image of a small part of the anatomical region, which is of most interest to the doctor, are called sighting (Appendix 3).
The method of radiography is used everywhere. It is available to all medical institutions, simple and easy for the patient. Pictures can be taken in a stationary X-ray room, in the ward, in the operating room, in the intensive care unit. A radiograph is a document that can be stored for a long time, used for comparison with repeated radiographs and presented for discussion to an unlimited number of specialists.
Indications for radiography are very wide, but in each individual case they must be justified, since X-ray examination is associated with radiation exposure. Relative contraindications are an extremely severe or highly agitated condition of the patient, as well as acute conditions requiring emergency surgical care (for example, bleeding from a large vessel, open pneumothorax).
Chest X-ray helps to identify pathological changes in soft tissues, chest bones and anatomical structures located in the chest cavity (lungs, pleura, mediastinum). Pneumonia is most commonly diagnosed on x-rays.
Advantages of radiography over fluoroscopy:
Great resolution;
Possibility of evaluation by many researchers and retrospective study of the image;
The possibility of long-term storage and comparison of images with repeated images in the process of dynamic monitoring of the patient;
Reducing radiation exposure to the patient.
The disadvantages of radiography include an increase in material costs when using it (radiographic film, photoreagents, etc.) and obtaining the desired image not immediately, but after a certain time.
3. Electroroentgenography - a method of obtaining an x-ray image on semiconductor wafers with its subsequent transfer to paper.
The electroradiographic image differs from the film image in two main features. The first is its large photographic latitude - both dense formations, in particular bones, and soft tissues are well displayed on the electroroentgenogram. The second feature is the phenomenon of contour underlining. On the border of fabrics of different density, they seem to be painted on.
The positive aspects of electroroentgenography are: 1) cost-effectiveness (cheap paper, for 1000 or more shots); 2) the speed of obtaining an image - only 2.5-3 minutes; 3) the study is carried out in a darkened room; 4) "dry" nature of image acquisition; 5) storage of electroroentgenograms is much easier than that of x-ray films.
On the electroroentgenograms of the respiratory organs, the pulmonary pattern is more clearly visible; it is possible to see the pulmonary arteries and veins. The contours of all pathological formations are more clearly defined - the presence of inclusions, destruction, changes in the surrounding lung tissue and the root of the lung, a “path” to the root, features of pathological changes in the wall and lumen of the bronchi. When comparing conventional radiographs with electroroentgenograms in patients with central and peripheral benign lung tumors, significant advantages of electroroentgenography were revealed. In cases of central tumors, the endobronchial part, its contours, the nature of the base, the degree of infiltration of the bronchus wall, the expansion or narrowing of the lumen of the bronchus, and changes in the root of the lung are much better visible (Appendix 4). With peripheral tumors, a very clear image of the contours of the tumor and inclusions in it is achieved. Electroradiography has stood the test of time and is now routinely used for all pathological formations in the lungs (Appendix 5).
4. Fluorography - a method of X-ray examination, which consists in photographing an image from an X-ray fluorescent screen onto a small format photographic film. Healthy lungs in the picture will look like a pattern of homogeneous, uniform tissue. On the fluorogram of diseased lungs in the affected areas, either darkened (indicating tissue inflammation) or, conversely, too bright spots will be visible. A dark spot indicates that the density of the lung tissues is increased, and a whitened pattern indicates an increased "airiness" of the lung tissues.
The main purpose of fluorography in our country is to conduct mass screening x-ray studies, mainly to detect latent lung lesions. Such fluorography is called verification or prophylactic. It is a method of selection from a population of persons with suspected disease, as well as a method of dispensary observation of people with inactive and residual tuberculous changes in the lungs, pneumosclerosis, cancer, etc. The frequency of screening examinations is determined taking into account the age of people, the nature of their work, local epidemiological conditions.
Important advantages of fluorography are the ability to examine a large number of people in a short time (high throughput), cost-effectiveness, and ease of storage of fluorograms. Comparison of fluorograms made during the next check-up examination with fluorograms of previous years allows early detection of minimal pathological changes in organs. This technique is called retrospective analysis of fluorograms.
5. Digital (digital) radiography. The x-ray imaging systems described above are referred to as conventional radiology. But in the family of these systems, a new child is rapidly growing and developing. These are digital (digital) methods of obtaining images (from the English digit - figure). In all digital devices, the image is constructed in principle the same way. Each "digital" picture consists of many individual dots. Digital information then enters the computer, where it is processed according to pre-compiled programs. The program is chosen by the doctor, based on the objectives of the study. With the help of a computer, you can improve the quality of the image: increase its contrast, clear it of interference, highlight details or contours that are of interest to the doctor.
Special methods include those that allow you to get an image on special installations designed to study certain organs and areas (mammography, orthopantomography).
Orthopantomography is a variant of sonography, which allows obtaining a detailed planar image of the jaws. The technique allows you to explore other parts of the facial skeleton (paranasal sinuses, eye sockets).
Mammography is an x-ray examination of the breast. It is performed to study the structure of the mammary gland when seals are found in it, as well as for a preventive purpose.
Special techniques also include a large group of X-ray contrast studies, in which images are obtained using artificial contrast (bronchography, angiography, excretory urography, etc.). The technique consists in introducing into the body substances that absorb (or, conversely, transmit) radiation much stronger (or weaker) than the organ under study.
Methods of X-ray examinations of the lungs. X-ray examination of the lungs plays an important role in modern clinical practice. Mostly X-ray examinations are performed.
The primary method of lung imaging is chest x-ray. Chest X-ray is certainly indicated for clinical suspicion of lung disease, chest trauma and polytrauma, in patients with an unclear cause of fever, and oncological diseases.
Radiography is survey and sighting. Overview images, as a rule, should be performed in two projections - frontal and lateral (with the side being examined to the cassette). Plain chest radiographs will always show both the anterior and posterior ribs, collarbone, scapula, spine, and sternum, regardless of the projection of the image (Figures 3.1 and 3.2). This is the difference between a plain radiograph and a tomogram.
Tomography. This technique is the next step in the X-ray examination (Fig. 3.3). Longitudinal direct tomography is more commonly used. The median cut is made at the level of half the thickness of the chest; the middle of the anterior-posterior diameter (from the back to the sternum) in an adult is 9-12 cm.
The anterior cut is 2 cm closer to the median anteriorly, and the posterior slice is 2 cm posterior to the median. On the median tomogram, shadows of either the anterior or posterior sections of the ribs will not be detected, on the anterior tomogram, the anterior sections of the ribs are well visualized, and on the posterior tomogram, on the contrary, the posterior sections of the ribs. Usually, topographic sections of the lungs can be most easily identified by these main features. Longitudinal tomography is used for:
- detailing the topography, shape, size, structure of pathological formations of the larynx, trachea and bronchi, roots of the lungs, pulmonary vessels, lymph nodes, pleura and mediastinum;
- study of the structure of pathological formation in the lung parenchyma (presence and features of destruction, calcification);
- clarification of the connection of the pathological formation with the root of the lung, with the vessels of the mediastinum, chest wall;
- detection of a pathological process with insufficiently informative radiographs;
- evaluation of the effectiveness of treatment.
CT. Computed tomography provides diagnostic information that is unattainable by other methods (Fig. 3.4).
CT is used for:
- detection of pathological changes hidden by pleural exudate;
- assessment of small-focal dissemination and diffuse interstitial lung lesions;
- differentiation of solid and liquid formations in the lungs;
- detection of focal lesions up to 15 mm in size;
- detection of larger foci of lesions with an unfavorable location for diagnosis or a slight increase in density;
- visualization of pathological formations of the mediastinum;
- assessment of intrathoracic lymph nodes. With CT, the lymph nodes of the roots of the lungs are visualized in size, starting from 10 mm (with conventional tomography - at least 20 mm). If the size is less than 1 cm, they are regarded as normal; from 1 to 1.5 cm - as suspicious; larger ones - as definitely pathological;
- solving the same issues as with conventional tomography and its lack of information;
- in case of possible surgical or radiation treatment.
X-ray. Transillumination of the chest organs as a primary study is not performed. Its advantage is real-time image acquisition, assessment of the movement of chest structures, multi-axis examination, which provides adequate spatial orientation and the choice of the optimal projection for targeted images. In addition, under the control of fluoroscopy, punctures and other manipulations on the chest organs are performed. Fluoroscopy is performed using an EOS.
Fluorography. As a screening method for lung imaging, fluorography is supplemented by full-format radiography in unclear cases, in the absence of positive dynamics within 10-14 days, or in all cases of detected pathological changes and with negative data that disagree with the clinical picture. In children, fluorography is not used because of the higher radiation exposure than with radiography.
Bronchography. The method of contrast study of the bronchial tree is called bronchography. The contrast agent for bronchography is most often yodolipol, an organic compound of iodine and vegetable oil with an iodine content of up to 40% (yodolipol). The introduction of a contrast agent into the tracheobronchial tree is performed in different ways. The most widely used methods using catheters are transnasal catheterization of the bronchi under local anesthesia and subanesthetic bronchography. After the introduction of a contrast agent into the tracheobronchial tree, serial images are taken, taking into account the sequence of contrasting the bronchial system.
As a result of the development of bronchoscopy based on fiber optics, the diagnostic value of bronchography has decreased. For most patients, the need for bronchography arises only in cases where bronchoscopy does not give satisfactory results.
Angiopulmonography is a technique of contrast examination of the vessels of the pulmonary circulation. More often, selective angiopulmonography is used, which consists in the introduction of a radiopaque catheter into the cubital vein, followed by passing it through the right cavities of the heart selectively to the left or right trunk of the pulmonary artery. The next stage of the study is the introduction of 15-20 ml of a 70% aqueous solution of a contrast agent under pressure and serial imaging. Indications for this method are diseases of the pulmonary vessels: embolism, arteriovenous aneurysms, pulmonary varicose veins, etc.
Radionuclide studies of the respiratory organs. Methods of radionuclide diagnostics are aimed at studying the three main physiological processes that form the basis of external respiration: alveolar ventilation, alveolar-capillary diffusion and capillary blood flow (perfusion) of the pulmonary artery system. Currently, practical medicine does not have more informative methods for registering regional blood flow and ventilation in the lungs.
To carry out this kind of research, two main types of radiopharmaceuticals are used: radioactive gases and radioactive particles.
regional ventilation. Radioactive gas 133 Xe is used (T½ biological - 1 min, T½ physical - 5.27 days, -, β-radiation). The study of alveolar ventilation and capillary blood flow using 133 Xe is carried out on multi-detector scintillation devices or a gamma camera.
Radiospirography (radiopneumography)
With intratracheal administration, 133 Xe spreads through various zones of the lungs, according to the level of ventilation of these zones. Pathological processes in the lungs, which lead to a local or diffuse violation of ventilation, reduce the amount of gas entering the affected areas. This is recorded using radiodiagnostic equipment. External recording of xenon -radiation makes it possible to obtain a graphical record of the level of ventilation and blood flow in any given area of the lung.
The patient inhales 133 Xe, when a plateau occurs, takes a deep breath and exhale (maximum). Immediately after washing out, the 2nd stage is carried out: an isotonic solution of NaCl with 133 Xe dissolved in it is injected intravenously, which diffuses into the alveoli and exhales.
To assess regional ventilation, the following indicators are determined:
− vital capacity of lungs (VC), in %;
− total lung capacity (TLC); V %,
− residual lung volume (VR);
is the half-life of the indicator.
To assess arterial blood flow, determine:
− amplitude height;
is the half-life of the indicator.
Intrapulmonary dynamics of 133 Xe depends on the degree of participation of the alveoli in external respiration and on the permeability of the alveolar-capillary membrane.
The height of the amplitude is directly proportional to the amount of radionuclide and, consequently, to the mass of blood.
Currently, Technegas is more often used to study the ventilation function of the lungs, which is nanoparticles (5-30 nm in diameter and 3 nm thick), consisting of 99m Tc, surrounded by a carbon shell, which are placed in an inert argon gas. "Technegaz" is inhaled into the lungs (Fig. 3.5.).
Perfusion lung scintigraphy. It is used to study pulmonary blood flow, usually to diagnose pulmonary embolism. The radiopharmaceutical is used - 99m Tc - macroaggregate of human serum. The principle of the method lies in the temporary blockade of a small part of the pulmonary capillaries. A few hours after the injection, the protein particles are destroyed by blood enzymes and macrophages. Violations of capillary blood flow are accompanied by a change in the normal accumulation of radiopharmaceuticals in the lungs.
PET is the best way to detect the prevalence of lung cancer. The study is carried out with radiopharmaceuticals - 18-fluorodeoxyglucose. The application of the method is constrained by its high cost.
Magnetic resonance imaging in the diagnosis of respiratory diseases
The use of MRI is mainly limited to the visualization of pathological formations of the mediastinum and roots of the lungs, lesions of the chest wall, the identification and characterization of diseases of the large vessels of the chest cavity, especially the aorta. The clinical significance of MRI of the lung parenchyma is low.
Ultrasound in the diagnosis of respiratory diseases. This method is of limited value in the diagnosis of most diseases of the chest (with the exception of diseases of the cardiovascular system). With its help, you can get information about the formations in contact with the chest or enclosed in it, about the pleural cavity (fluid and dense formations) and the diaphragm (about movement and shape), as well as about formations located in certain parts of the mediastinum (for example, about thymus).
The branch of radiology devoted to the study of the respiratory system is called roentgenopulmonology. Since the discovery of X-rays and their application in medical practice, the respiratory organs have been the subject of the most frequent and massive study. There are other methods for studying the respiratory system, but the importance of x-rays cannot be overestimated, due to the ability to obtain and store a direct visual image of the objects under study.
X-rays of light performed using a fluorograph, a special apparatus designed for mass research. An automatic removable device allows examining a large number of patients in a short time, but the reduced image does not provide an opportunity to identify all possible pathologies, therefore, in doubtful cases, additional diagnostic methods are used. A fluorogram differs from a conventional x-ray only in size.
It is an erroneous opinion that any doctor who knows the anatomy and clinic of diseases of the respiratory system is able to correctly analyze the X-ray of the lungs. Without special training, this can lead to a large number of diagnostic errors. Lung tissue is a very complex structure, it consists of many alveoli penetrated by blood, lymphatic vessels, a network of bronchi and nerves. Each anatomical structure has a different density and gives an image of different intensity.
Also, any organ undergoes age-related changes that differ from the norm, but do not need treatment. In addition, any pathological formation has a number of characteristic features for it. The conditions for performing an x-ray of the lungs also leave their mark. Therefore, only a specialist radiologist, who undergoes special training, studying all the special conditions, can reliably analyze the results obtained.
X-ray examinations are preventive and diagnostic:
Preventive studies are carried out in order to detect tuberculosis and oncological processes in the early stages. These diseases develop rather slowly and are asymptomatic for a long time. Statistics say that 40 - 60% of lung pathology is detected during preventive examinations. This oddity is due to the special physiology of the lungs, they greatly change their volume when breathing, therefore they do not have pain nerve endings, otherwise a person would experience unbearable pain. A pain reaction in pulmonary diseases occurs when nearby organs and tissues are involved in the disease process.
According to the law, all citizens over the age of 15 are required to undergo an inspection, once every two years. An exception is made by persons with occupational hazards, working at food enterprises or in children's institutions, who had contact with a patient with tuberculosis. They have special examination schedules.
Taking into account the unfavorable situation in the CIS countries regarding tuberculosis, I would like to note that from the moment of infection to the appearance of the first x-ray signs of the disease, it takes from two months to six months. Given this circumstance, it is more expedient to undergo fluorography annually. Indications for x-ray of the lungs are:
1. Persistent cough, more than 3 months, which may be a symptom of tuberculosis or cancer.
2. Prolonged temperature increase of 37 - 38 degrees C, to exclude pathological processes in the lower respiratory tract.
3. The presence of diagnosed oncological processes in other organs, in order to identify metastases, which often appear in the lungs due to increased blood circulation.
4. Identified changes on the X-ray, to clarify the diagnosis.
5. Acute respiratory diseases, give complications in the form of inflammation of the lung tissue.
6. Clarification of localization, depth and area of lung lesions, in such cases, special X-ray equipment is used: conventional and computed tomography.
How are the lungs examined with an x-ray?
Chest X-ray- obtaining a flat image of the organ on film, the image is examined and evaluated.
Fluoroscopy - the doctor sees the patient on the screen, can examine the lungs in different projections, while moving while breathing. It is prescribed to clarify the diagnosis after the detection of pathological changes on the radiograph.
Tomography - a layer-by-layer series of radiographs, performed using special technologies, allows you to clarify the localization of the process, to obtain additional information about the focus of the disease. Now X-ray tomographs are gradually being replaced by computer technologies, which provide much more information necessary for the doctor.
Bronchography is a study of the bronchial tree using contrast agents. On a conventional radiograph, it is impossible to reliably assess this system as a whole. The contrast agent allows you to diagnose a foreign body, the initial stages of central cancer and other bronchial diseases with the exact location of the process.
Proper positioning of the patient is essential in any type of x-ray examination. Long-term observations have shown that images obtained under different conditions carry different information. For example, a traditional examination of the chest is performed in a standing position, holding the breath in the deep inspiration phase. This allows you to maximize the visibility of the lung fields, some of which are hidden by the diaphragm. If the state of severity of the patient does not allow the use of classical styling, the picture is taken in the supine position, and the laboratory assistant must mark the x-ray.
If the patient does not exactly follow the instructions of the staff, the image may not be clear, the necessary objects will not be visible enough, the radiograph will be unsuitable for analysis. We will have to conduct a second study, and this is an additional dose of radiation. The patient must remember that the quality of the study performed largely depends on him, and not only on the qualifications of the personnel of the radiological rooms.
Many medical institutions give out the results of the examinations to the hands of the patient. X-rays are a reliable medical document, so they must be kept. If any disease is detected, X-ray control is carried out. Archival images will help the radiologist in evaluating subsequent images. Comparative characteristics of a series of radiographs will additionally inform about the rate of progression of the disease, about the effectiveness of treatment. This is especially important if the examination is carried out by different specialists in several medical institutions. The presence of the necessary documentation on the hands of the patient will ensure his right to choose a doctor, without the need to perform repeated images. A well-made, marked, according to generally accepted rules, snapshot is just such a document.
X-ray images must not be folded, rolled up, they must be stored in a dark, dry place, in special folders. If you already have images of the organ that you are examining, take them with you again.
Is a lung x-ray dangerous for health?
You can judge for yourself how dangerous X-ray examinations are for health. According to the law, the permissible total dose of radiation per year:
- for an absolutely healthy person - 2 mSv,
- for outpatients - 20 mSv,
- for oncological and tuberculosis patients - up to 100 mSv.
When performing one x-ray of the lungs, the patient receives a dose of 0.25 mSv. The human body completely neutralizes the effects of radiation over time. The dose received during X-ray of the lungs and other similar studies should be recorded in the patient's outpatient record, where he can independently calculate the total annual dose.
Now consider that a person does not know about his disease, does not receive timely treatment, and meanwhile the disease destroys the affected organ. A patient with tuberculosis also poses a danger to others, and to those closest to him. Of course, such diagnostic procedures as X-rays of the lungs should not be carried out out of curiosity, each appointment must be justified. However, there are situations in medicine when, in order to save the patient's life, one can neglect the insignificant harm caused by x-rays.
Instrumental methods for examining the respiratory organs include: fluoroscopy (transmission of the chest in front of the screen), radiography (producing an x-ray), bronchography, tracheobronchoscopy, thoracoscopy, spirometry, spirography, pneumotachometry, pneumotachography, oxygemometry, oxyhemography and some other research methods.
X-ray examination is so important that in many cases it is impossible to do without it for the correct recognition of respiratory diseases.
In view of the comprehensive significance of X-ray examination for the diagnosis of various diseases, X-ray studies are generally taught in special departments or courses. Therefore, we will confine ourselves here to a brief summary of the basic principles of this most important method.
X-rays, like the visible rays of the sun, have the property of decomposing silver bromide on a light-sensitive plate or film, so an X-ray image can be photographed. The method of taking photographs using X-rays is called radiography, and the resulting images are called radiographs.
Usually, in a clinic or hospital, a chest x-ray is performed. If necessary, to clarify the diagnosis and for the purpose of documentation, a chest x-ray is performed.
In a healthy person, chest X-ray shows the lungs on the screen as two light fields with a grid consisting of the shadow of blood vessels, large and medium bronchi, more pronounced at the roots of the lungs. The light fields of the lungs and the network of vessels and bronchi are an x-ray pulmonary root pattern. When you inhale, the lungs become more transparent. This is especially clear in the sinuses. When breathing deeply, the movement of the diaphragm is clearly visible. This makes it possible to judge the excursion of the lower edge of the lungs and identify possible pleural adhesions, the presence of pleural effusion, etc.
X-ray and chest x-ray make it possible to recognize the appearance of compacted, airless areas in the lungs (for example, with pulmonary tuberculosis, lung cancer, pneumonia), to determine the increased airiness of the lungs with emphysema, the presence of air-containing cavities in the lungs (abscess, cavern), growth in lung connective tissue strands (with pneumosclerosis), thickening and thickening of the walls of the pulmonary vessels (with their sclerosis), accumulation of liquid or gas in the pleural cavity, presence of a foreign body in the lung (bullet, projectile fragments, etc.).
The X-ray method of examining the chest organs with pathological changes in the lungs, bronchi or pleura allows you to monitor the dynamics over the course of the disease and compare research data to judge certain changes in the respiratory organs that occur over a certain time, and also makes it possible to monitor the effectiveness of the treatment.
With the introduction into the bronchi of contrast agents that delay x-rays, such as iodolipol, an image of the bronchial tree is obtained on the radiograph. This method of examination of the bronchi, called bronchography, makes it possible to diagnose bronchiectasis, curvature of the bronchi, narrowing of their lumen, etc.
The method of fluorography has become widespread. It consists of producing a series of small photographs from x-ray images on a screen. This method makes it possible to study a large number of people in a short time and is indispensable for examining the collectives of schools, factories, factories, and collective farms. Fluorography is carried out by a fluorograph - a special attachment to the x-ray machine. Fluorograms after development are viewed through a special photographic enlarger.
The method of tomography makes it possible to obtain layer-by-layer (at different depths) radiographs. With this method of X-ray examination, the clearest images are obtained only in a certain plane at a predetermined depth. Lung structures located in other planes do not give a sharp image due to a specially moving x-ray tube. This method provides valuable data for the differential diagnosis of tumors, infiltrates, abscesses, caverns located at different depths. Tomofluorography makes it possible to obtain layered fluorograms.
Tracheobronchoscopy. This is the name of the method of direct examination of the trachea (tracheoscopy) and bronchi (bronchoscopy), which consists in introducing a special tube equipped with a lighting device (bronchoscope) into the trachea or into the bronchi. The tube is inserted either through the mouth into the larynx (upper tracheobronchoscopy) or, if necessary, through the tracheotomy opening (lower tracheobronchoscopy). This method makes it possible, by examining the mucosa of the trachea, the main bronchi and their nearest branches, to detect various pathological processes in them (inflammation, polyps, tumors, etc.). Contraindications to the use of tracheobronchoscopy are severe cardiac dysfunction, a high degree of arterial hypertension, laryngeal tuberculosis, pneumonia, and acute pleurisy. With the help of a bronchoscope, a biopsy of the mucosa of the trachea or bronchi is performed (taking a piece of tissue for histological examination), washing the bronchi and injecting drugs directly into the lungs.
Thoracoscopy. With the help of a special device - a thoracoscope - they examine the pleural cavity and separate the adhesions between the visceral. Spirometer. parietal pleura formed after pleurisy or pneumothorax. A thoracoscope is a tube with an optical device for visual observation of the pleural cavity. The thoracoscope is inserted through a special trocar after puncturing the chest and applying an artificial pneumothorax.
Spirometry. Spirometry is a method of measuring the vital capacity of the lungs.
To measure the vital capacity of the lungs, a device called a spirometer is used, it consists of two metal cylinders, and the smaller one with an open bottom is inserted into the larger one, open at the top. The large cylinder is filled with water. Through a wide rubber tube, put on a tap in the upper wall of a smaller cylinder, the subject, after a maximum breath, exhales air to failure. Entering the smaller cylinder, the air causes it to rise above the water. The height of its rise is marked on a scale, indicating the volume of air entering the smaller cylinder.
As you know, during quiet breathing during one respiratory movement, a healthy adult inhales and exhales an average of 500 ohm3 of air. This amount of air is called the tidal volume. If, after a normal breath, you take the deepest possible breath, then you can enter about 1500 cm3 of air into the lungs. This amount is called additional volume. If, after a normal exhalation, exhale as deeply as possible, then you can exhale about 1500 cm3 of air. This quantity is called reserve (reserve) volume. The sum of respiratory, additional and residual volumes is the so-called vital capacity of the lungs.
Normally, the vital capacity of the lungs in men is equal to cm3, in women it is 00 cm3. These values may fluctuate somewhat depending on the physique, age, height, weight, training, etc. In view of this, the diagnostic value is not so much the absolute value of the vital capacity of the lungs, but its fluctuation in the same patient as the condition worsens or improves. . The value of the vital capacity of the lungs decreases in a number of diseases leading to a decrease in the respiratory excursion of the lungs and their respiratory surface, for example, in emphysema, pneumonia, tuberculosis, neoplasms, congestive lung, pleurisy, pneumothorax, etc. Systematic measurement of the value of the vital capacity of the lungs gives the ability to get an idea of the progression or attenuation of the pathological process.
Spirography. Measurement and graphic registration of respiratory volumes is carried out using spirography. For spirography, devices called spirographs are used. A spirograph is a spirometer connected to a kymograph. The spirogram is recorded on a moving tape. Knowing the scale of the spirograph scale and the speed of the paper, it is possible to determine the main indicators of external respiration. In addition to determining lung volumes and lung capacity with the help of spirography, it is also possible to determine indicators of pulmonary ventilation: minute respiratory volume (the sum of respiratory volumes in 1 minute), maximum ventilation of the lungs (the maximum amount of air that can be ventilated for 1 minute), the volume of forced expiration, as well as indicators of pulmonary gas exchange: oxygen uptake in 1 min, carbon dioxide release and some other indicators.
Pneumotachometry and pneumotachography. Significant importance in the study of respiration is acquired by methods for studying the mechanics of respiration: the volumetric rate of inhalation and exhalation (calm or forced), the duration of various phases of the respiratory cycle, the minute volume of ventilation, intraalveolar pressure, etc. These indicators are recorded using devices - pneumotachometer and pneumotachograph. The principle of operation of these devices is to register changes in the pressure of the air flow that occurs during breathing using a membrane manometer with a pointer or optical indicator. In optical recording, the curve is recorded on moving photographic paper.
Oxygemometry and oxygemography. These methods are used to study the saturation (oxygenation) of blood with oxygen. The principle of oxyhemometry and oxyhemography is based on the features of the absorption spectra of oxyhemoglobin and reduced hemoglobin. In contrast to the bloody method of studying blood oxygen saturation, when blood is taken by puncturing an artery and the study is carried out using the Van Slyk apparatus, oxyhemometry and oxyhemography are carried out in a bloodless way. To do this, use the devices oximeter or oxyhemograph. With the help of these devices, it is possible to study changes in arterial oxygen saturation over a long period of time during functional loads, oxygen therapy, anesthesia, operations, etc. These devices consist of an ear sensor with semiconductor photocells, which is the photometric part of the device, and a measuring unit with a scale graduated in percent oxygen saturation. Changes in the color of blood at different degrees of saturation with oxygen are captured by photoelectric converters. With the help of semiconductor photocells, changes in the color of the blood are converted into changes in the photocurrent, which is recorded by the device. The ear probe is put on the upper part of the auricle of the examined person. With the help of an oxyhemograph, a graphic registration of blood oxygen saturation is performed. The saturation curve is called an oxyhemogram.
This brief review of instrumental research methods does not exhaust all existing methods for studying the function of external respiration. Along with physical methods, instrumental methods provide valuable data necessary for assessing the functional state of the respiratory system.
Puncture of the chest wall (thoracocentesis). Physical methods of examination of the chest, including fluoroscopy, as a rule, make it possible to establish the presence of fluid in the pleural cavity, but do not make it possible to determine whether the fluid is exudate or transudate, and in the first case, the nature of the exudate. Known help in this regard is provided by a general examination of the patient and observation of the course of the disease: in the presence of fluid in the pleural cavity, fever, pain in the side, dry cough, pleural friction noise at the border of dullness indicate the presence of exudate. The absence of fever and pain, swelling in other areas of the body in the presence of heart or kidney disease indicate the presence of transudate, especially if the fluid is determined in both pleural cavities. With undoubted exudative pleurisy, a more serious condition of the patient, a very high temperature with large fluctuations, rapidly developing shortness of breath and palpitations, chills and sweats, a sharp pallor of the skin, high leukocytosis and a shift of the leukocyte formula to the left (see "Blood test") indicate a purulent character exudate.
However, the question of the presence of fluid in the pleural cavity and the nature of the fluid can be finally resolved only by obtaining it and subsequent research. To obtain fluid from the pleural cavity, a puncture of the chest wall is used (trial puncture of the pleura, pleural puncture).
Pleural puncture is used for both diagnostic and therapeutic purposes, namely: if it is necessary to remove fluid from the pleural cavity, to introduce various drugs or gas into the pleural cavity to compress the lung (artificial pneumothorax in the treatment of pulmonary tuberculosis).
The puncture of the pleural cavity is performed with a special needle (8-10 cm long) of medium caliber (more than 1 mm) attached to a 20-gram syringe. Before use, the disassembled syringe and needle are sterilized by boiling. To avoid clogging, the needle must be equipped with a mandrin, with which it is sterilized.
Usually the puncture is made below the angle of the scapula or between the scapular and posterior axillary lines in the VIII or IX intercostal space, where there is the greatest dullness. With encysted pleurisy, a puncture is made at the site of the most intense dullness. The puncture site should be chosen not too low and not too close to the upper level of dullness. If the puncture is too low, you can get into the pleural sinus, in which there may be no fluid due to gluing of the parietal and diaphragmatic pleura. If, however, the puncture is made too close to the upper level of dullness, then one can get into the lung lying above the liquid, which, due to atelectasis, can also give dullness during percussion and thereby simulate a higher standing of the liquid.
The injection is made in the intercostal space closer to the upper edge of the underlying rib in order to avoid injury to the intercostal artery passing in the groove along the lower edge of the overlying rib. Invagination of the skin during the passage of the needle causes unnecessary pain. To prevent this, as well as to give the needle greater stability, before the injection, stretch the skin of the intercostal space between the thumb and forefinger of the left hand, placed one on the overlying and the other on the underlying rib. The needle is set strictly perpendicular to the surface of the intercostal space, sticks not too slowly, so as not to cause pain, but not too fast, so that the needle does not slip through the pleural cavity into the lung or break, accidentally hitting the rib.
When piercing the chest wall, resistance is first felt when the needle passes through the tissues of the intercostal space, and then a sensation is created of the needle entering the hollow space. If the needle rests against the rib, then it should be slightly stretched out to slightly change the direction of the puncture. When liquid appears, it should not be sucked into the syringe too quickly to avoid suction of ambient air. If, when trying to pull out the piston, resistance is felt in the form of a reverse suction, then this indicates that the tip of the needle is in dense tissue. The piston is easily pulled out, but the liquid is not shown if the needle is in an air-containing cavity (pneumothorax, bronchus), or when the needle is loosely attached to the cannula. The appearance of clear blood in the syringe may depend on the needle entering a blood vessel or lung tissue. In this case, the needle should be removed immediately (unless there is evidence that the appearance of blood depends on the presence of hemothorax).
To extract a large amount of fluid from the pleural cavity, the Poten apparatus is used.
Examination of the fluid obtained by puncture. First of all, the study must decide whether the fluid is exudate or transudate. For this, physical, chemical and microscopic examination of the liquid is used. In some cases, bacteriological examination is also performed to determine the etiology of inflammation of the pleura or other serous membrane.
In a physical examination, the color, transparency and specific gravity of the liquid are determined.
Transudate is a completely transparent, slightly yellowish, and sometimes colorless liquid. Serous and serofibrinous exudate is usually more intense lemon yellow and less transparent. In the exudate, when it stands, more or less abundant flakes of fibrin fall out, which makes it cloudy, while the transudate remains transparent, and no sediment forms in it at all, or the latter is very gentle and looks like a cloud.
Purulent exudate - thick, greenish, opaque. Hemorrhagic exudate is opaque, red in color, sometimes as a result of the breakdown of erythrocytes that has already occurred in the pleural cavity - reddish-brown. Putrid exudate is dirty-brown in color and has an unpleasant gangrenous odor.
Purulent, putrefactive and hemorrhagic exudates are easily identified by their appearance. Difficulty may present when differentiating transudate and serous exudate, which may be similar in color and transparency. They can be distinguished by determining the specific gravity. Due to the higher content of protein and formed elements in the exudate, its specific gravity is higher than 1016, and the transudate is lower than 1014.
Chemical examination of the liquid obtained by puncture usually comes down to determining the percentage of protein. The presence of more than 4% protein in the extracted fluid speaks in favor of exudate, and below 2% - in favor of transudate. However, it should be remembered that in transudates that have been in body cavities for a long time, the percentage of protein increases over time, on the one hand, due to the absorption of the liquid parts of the transudate, and on the other hand, due to the inflammatory reaction of the serous membrane to prolonged irritation by its stagnant fluid.
To distinguish exudate from transudate, a Rivalta test is also performed. This test serves to detect a special protein body that is contained in exudates, but is absent or present only in the form of traces in transudates. This protein body is seromucin.
The Rivalta test is made as follows: water in a glass cylinder is acidified with 2-3 drops of strong (80% solution) acetic acid. Then a few drops of the test liquid are dropped into the resulting solution from a pipette one after the other. If the latter is an exudate, then after each falling drop in the water a white cloud stretches, resembling cigarette smoke. If the liquid under study is a transudate, then its drops fall to the bottom of the cylinder, leaving no such trace behind.
Microscopic examination provides a further opportunity to distinguish exudate from transudate. The investigated liquid is usually centrifuged and a smear is prepared from the resulting sediment on a glass slide; it is examined under a microscope in a fresh state or is preliminarily fixed and stained in the same way as blood.
The main significance of the microscopic examination of the smear is to determine the number of leukocytes in the test fluid, however, during centrifugation, the density of the resulting sediment depends on the duration of centrifugation and on the number of revolutions per minute. Therefore, it is preferable to use a sediment of a non-centrifuged liquid (F. G. Yanovsky). In repeated studies, the liquid after receiving it is poured into identical test tubes to the same level and left for the same time (for example, for 1 hour). This eliminates possible randomness in the distribution of leukocytes in the sediment. After the specified time has elapsed, carefully (in order to avoid stirring the loose sediment) with a pipette, a few drops are collected from the bottom of the test tube and applied to a glass slide to prepare a smear.
When examined under a microscope, erythrocytes are often found in a smear. The abundance of red blood cells in the smear is observed with hemorrhagic exudates, which are characteristic of malignant neoplasms of the serous membranes. They occur with tuberculous and traumatic pleurisy, with uremia, with pleurisy in patients suffering from bleeding, sometimes with pleurisy, complicating pulmonary infarction. A significant amount of fresh erythrocytes is sometimes observed in a smear from serous exudates and even from transudates. The reason for this is the admixture of blood due to injury to the vessel during the puncture. So an impurity can sometimes be detected macroscopically (pinkish color of the liquid), but only in the first portions of the liquid. In addition, true hemorrhagic exudates are not bright red, like a liquid in the presence of fresh blood, but rather brownish red due to hemolysis of erythrocytes and accumulation of hemoglobin conversion products.
To decide whether the resulting liquid represents pure blood from a wounded vessel or a mixture of blood with exudate, one can compare the number of red blood cells in 1 ml of the obtained liquid with the number of red blood cells in 1 ml of blood from the finger pulp of the same patient. For the same purpose, it is possible to determine the ratio of the number of erythrocytes to the number of leukocytes in 1 ml in the received bloody liquid (it is much less in bloody exudate than in pure blood).
An important diagnostic value is the number of leukocytes in a smear from the test fluid. The abundant content of leukocytes (10-15 or more) in the field of view in a smear from a non-centrifuged fluid at high magnification indicates an inflammatory origin of the fluid. The more intense the inflammatory process, the more leukocytes in the exudate. In purulent exudates, leukocytes can cover the entire field of view, and in purulent exudates of tuberculous origin, leukocytes are usually in a state of granular and fatty decay, while in purulent exudates caused by ordinary pyogenic bacteria (strepto-, staphylo-, pneumococci), leukocytes are often well preserved. Another distinguishing feature of tuberculous purulent exudate is that tubercle bacilli are not detected in it under a microscope or are detected with difficulty, and then with the help of special methods, while in a purulent exudate of non-tuberculous origin, the causative agent of suppuration is easily detected.
Microscopic examination of stained smears of exudate can also determine the percentage of different types of leukocytes.
The predominance of lymphocytes (up to 70% and above) is considered characteristic of the exudate of tuberculous etiology, while the predominance of neutrophilic leukocytes is considered characteristic of the exudate of another etiology. The predominance of lymphocytes is also observed in exudates of syphilitic etiology, as well as in exudates arising from malignant neoplasms of the pleura and other serous membranes. On the other hand, the predominance of one or another type of leukocyte also depends on the intensity and duration of the inflammatory process. So, for example, at the height of tuberculous pleurisy, neutrophils may predominate in the exudate, and during the period of recovery from non-tuberculous pleurisy, large numbers of lymphocytes may occur in the smear.
Microscopic examination of the transudate in the sediment often reveals cells of the exfoliated endothelium of the serous membrane. These are large polyhedral cells, either single or arranged in groups of 8-10, partially possessing the characteristic structure of the endothelium, partially degenerated and, as a result, have lost their normal shape and size. Their appearance depends on the desquamation of the endothelium due to mechanical irritation of the serous membrane with transudate.
With neoplasms of the pleura or other serous membranes in the exudate, tumor cells can sometimes be detected under a microscope.
With leukemia in abdominal exudates, immature forms of leukocytes characteristic of this form of leukemia can be detected. In some diseases (tuberculosis, gangrene, lung cancer), in rare cases, numerous eosinophils can be found in the pleural exudate, sometimes over 50%. The reason for their appearance is not exactly clear. Sometimes this is due to the migration of roundworm larvae.
In some cases, a puncture of the pleura or peritoneum produces a liquid that looks like milk. There are three types of such fluid: chylous, chiloform and pseudochylous exudates.
Chylous exudate is the result of chyle leakage due to traumatic rupture of the thoracic lymphatic duct or other large lymphatic vessels. Sometimes, even with a simple stagnation of lymph in the thoracic duct, tiny droplets of fat can penetrate into the abdominal fluid. When defending chylous exudate, fat accumulates on top in the form of a creamy layer. Droplets of fat in chylous exudate are easily detected under a microscope with the appropriate color of the smear (they are stained black with osmic acid or red with Sudan III). Such an exudate is clarified by the addition of ether.
Chiloform exudate contains a large number of decayed fat cells. It is sometimes seen in tuberculosis, syphilis, and malignant neoplasm of the pleura.
Pseudo-chylous exudate is turbid, looks like milk diluted with water, but does not contain fat. From the addition of ether, unlike chylous exudate, it does not become clear, and when standing does not form an upper creamy layer. In contrast to the chiloform exudate, microscopic examination does not find decayed fat cells in it. The milky color depends on the special state of aggregation of protein bodies. Such exudate occurs most often with syphilis of the serous membranes.
Respiratory examination:
Instrumental and laboratory methods for the study of respiratory organs
Of the radiological methods for examining the respiratory organs, chest roentgenoscopy, radiography, tomography, bronchography and fluorography are used.
The most common research method is fluoroscopy lungs, which allows to determine the transparency of the lung fields, detect foci of compaction (infiltrates, pneumosclerosis, neoplasms) and cavities in the lung tissue, foreign bodies of the trachea and bronchi, detect the presence of fluid or air in the pleural cavity, as well as coarse pleural adhesions and mooring.
Radiography it is used for the purpose of diagnosing and recording pathological changes in the respiratory organs detected during fluoroscopy on x-ray film; some changes (unsharp focal seals, bronchovascular pattern, etc.) are better defined on the radiograph than on fluoroscopy. Tomography allows for layer-by-layer X-ray examination of the lungs. It is used for more accurate diagnosis of tumors, as well as small infiltrates, cavities and caverns. Bronchography used to study the bronchi. The patient, after preliminary anesthesia of the respiratory tract, is injected into the lumen of the bronchi with a contrast agent (iodolipol), which delays x-rays. Then radiographs of the lungs are taken, on which a clear image of the bronchial tree is obtained. This method allows you to detect bronchiectasis, abscesses and cavities of the lungs, narrowing of the bronchial lumen by a tumor. Fluorography is a type of x-ray examination of the lungs, in which a photograph is taken on a small-format reel film. It is used for mass preventive examination of the population.
Currently, research methods based on advanced modern technologies are widely used - computed tomography and magnetic resonance imaging.
Endoscopy
Endoscopic examination methods include bronchoscopy and thoracoscopy. Bronchoscopy used to examine the mucous membrane of the trachea and bronchi. It is produced by a special device - a bronchofiberscope. Special forceps are attached to the bronchoscope for biopsy, extraction of foreign bodies, removal of polyps, photo attachment, etc.
Bronchoscopy is used to diagnose erosions and ulcers of the bronchial mucosa and tumors of the bronchial wall, extract foreign bodies, remove bronchial polyps, treat bronchiectasis and centrally located lung abscesses. In these cases, purulent sputum is first aspirated through a bronchofibroscope, and then antibiotics are injected into the lumen of the bronchi or cavity.
Thoracoscopy It is produced by a special device - a thoracoscope, which consists of a hollow metal tube and a special optical device with an electric light bulb. It is used to examine the visceral and parietal pleura and disconnect pleural adhesions that prevent the imposition of artificial pneumothorax (with cavernous pulmonary tuberculosis).
Methods of functional diagnostics
Methods of functional study of the external respiration system are of great importance in a comprehensive examination of patients suffering from diseases of the lungs and bronchi. All these methods do not allow diagnosing the disease that led to respiratory failure, however, they make it possible to identify its presence, often long before the onset of the first clinical symptoms, to establish the type, nature and severity of this failure, to trace the dynamics of changes in the functions of the respiratory apparatus in the process of disease development. and influenced by treatment.
Spirography is the registration of ventilation values (respiratory fluctuations) on a moving millimetric tape of a spirograph. Knowing the scale of the spirograph scale and the speed of the paper, the main lung volumes and capacities are calculated. The most important for assessing the function of external respiration are the vital capacity (VC), maximum pulmonary ventilation (MLV), their relationship.
Spirometry is a method of recording changes in lung volumes during breathing maneuvers over time.
Pneumotachometry is a method that allows you to build flow-volume curves that provide additional information about violations of the function of external respiration by analyzing the "loop" that reflects changes in the speed of movement of exhaled and inhaled air depending on the volume of the lung. Using the method, it is possible to study violations of bronchial patency at the level of large, medium or small bronchi, which is important in determining the therapy of bronchial obstruction.
Peak flowmetry is a method of measuring peak expiratory flow (PEV) - the maximum air velocity during a forced exhalation after a full breath. The introduction of the peak flow meter (a portable device for personal use) is the most important advance in asthma diagnosis and treatment monitoring.
There are several types of peak flow meters. All of them are standardized. The patient chooses any type of device for himself and begins to use it in a certain sequence:
Puts the mouthpiece head on the peak flowmeter;
Stand up and hold the peak flow meter horizontally. The slider on the device must be stationary and be at the beginning of the scale;
Takes a deep breath, puts his lips around the mouthpiece and exhales as quickly as possible;
Marks the result. Then repeat the procedure twice. Selects the highest score and marks it. Compares received data with due ones.
Methods for examining the lungs
Methods for studying the respiratory organs can be divided into two groups: general and laboratory-instrumental. Below we will consider each group separately.
Methods for examining the lungs
General lung examination methods
Common methods for examining the respiratory organs include:
Examination of the chest is necessary to determine its shape and symmetry, the type of breathing, its frequency and rhythm. At the examination stage, asymmetries are revealed, and the uniformity of the participation of the chest in the breathing process is also examined.
Palpation (palpation) helps to identify painful areas and their extent. With its help, the elasticity of the chest and "voice trembling" are also determined.
Percussion (tapping) is used both to determine the boundaries of the lungs and to identify various deviations in their functioning. The conclusion about the state of the respiratory organs is made on the basis of the sound received during percussion.
Laboratory and instrumental methods for examining the lungs
Laboratory and instrumental studies can be divided into two groups: main and auxiliary.
The main group is research conducted using X-ray techniques. This includes fluorography, radiography and fluoroscopy.
Fluorography is a picture of the respiratory organs. This method is widely used for mass surveys. Fluorographic images help to identify diseases of the respiratory system. If pathologies are found in the picture or there are suspicions of them, then the patient is sent for further examination.
X-ray is also a picture of the lungs, but it allows you to see the respiratory organs in more detail, as well as examine in detail any part of the lung. Radiography allows you to take pictures of the lungs in different projections, which greatly simplifies the diagnosis.
X-ray is a transillumination of the respiratory organs. A picture is not taken during such a study, the results of the study are available only in real time on the monitor, so the professionalism of the radiologist is of great importance here.
Auxiliary laboratory and instrumental research methods include:
Computed and linear tomography
Linear and computed tomography is a layered study of the lungs. The images obtained during such studies help to identify enlarged lymph nodes in the roots of the lungs, to determine the structure of pathological changes in the respiratory system.
If chronic diseases and tumors are suspected, the patient is given bronchography (a catheter is inserted into the bronchi through which an iodine-containing substance is supplied). Bronchography is performed under local or general anesthesia, depending on which area of the bronchi is to be examined.
Sputum studies
Sputum is examined in two ways: microscopic and bacterioscopic.
Bronchoscopy is a type of visual examination in which a special tube (bronchoscope) is inserted into the trachea. This method is suitable for examining the lower respiratory tract. Bronchoscopy is necessary to determine the causes of a prolonged cough, as well as if breathing is difficult due to foreign bodies that have entered the lungs. Bronchoscopy is used not only for diagnosis, but also for the treatment of respiratory diseases. With the help of a bronchoscope, drugs are introduced into the airways, and a biopsy can also be performed. The procedure is performed under general or local anesthesia.
Laryngoscopy is the main method for examining the larynx, performed using a laryngeal mirror (indirect laryngoscopy) or directoscopes (direct laryngoscopy). Due to the fact that during indirect laryngoscopy a gag reflex often occurs, it can be performed under local anesthesia (application anesthesia of the pharynx and root of the tongue). Direct laryngoscopy is performed under general anesthesia or local anesthesia.
Thoracoscopy - examination of the lungs and pleura through a special instrument (thoracoscope). The procedure is performed under general anesthesia and requires hospitalization. A thoracoscope can be used to inject drugs into the lungs, remove fluid from the pleural cavity, and take tissue samples for research.