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Practical task that should be performed during practical training

1. Performing comparative percussion of the chest

2. Recognizing percussion sounds.

3. Performing topographic percussion of the lung

4. Recognizing and assessing changes of percussion sound and position of the lung

Topic content

Percussion is a method of objective study consisting in tapping the patient's body to evaluate the physical properties of the underlying organs according to the character of the artificially produced sounds.

There are two types of percussion: immediate and mediate. Immediate (direct) percussion consists in tapping the patient's body with one or several fingers. In indirect (mediate) percussion the tapping is performed on some object applied to the studied area. A so-called plessimeter, a plate of a dense material, is used. A finger of the doctor applied to the surface of the body may play a role of this instrument. Striking the plessimeter is done using a percussion hammer or a.finger. At direct percussion, the sound is low and indistinct, as a large portion of the energy is used by compression of the soft tissues. In indirect percussion, the plessimeter, compressing the soft tissue, limits the propagation of the energy directing it to the depth. The sound is loud. This type of percussion is painless. The most frequent method of indirect percussion is tapping with a finger on the finger.

Physical grounds of percussion

Percussion is based on obtaining a sound wave from the tissues as a result of their shacking on striking. Vibrations of the sounding bodies are due to their elasticity (air, metallic plate) or are produced under the influence of elasticity obtained with the body strain (string, membrane). The hearing threshold in people correspond to the range of 1620 vibrations per second.

Sound is produced by striking a hard or liquid body. The source of the sound wave is vibrations of the particles of the body produced by the striking. On striking a homogeneous body all particles produce vibrations of the same wave length (periodic vibrations). Periodic vibrations produce the tone termed sound. If an inhomogeneous body is stricken, this produces non-periodic vibrations because various in structure portions of the body produce vibrations of various lengths. These complicated sounds with non-periodic vibrations are termed murmur.

From the physical perspective, the sounds can be classified as to the loudness, duration, pitch; a special property (timber), i.e. tympanic character is also distinguished. The former three properties depend largely on the mass, density and strain of the object as well as the force of the strike. As the physician uses the taps of the same force and tissue mass is constant, the properties of the sound depend mainly on the density and strain of the studied tissue.

Loudness of the percussion sound depends inversely on the density (strain) of the tissue. The higher is the density, the weaker is the loudness. The air in the cavities and tissues produces a loud sound. The more air is present in the tissue, the lower is the tissue density, the louder is the sound on percussion. The bones andstrained membranes (the walls of the alveoli) are especially dense; the percussion produces a low sound. The liver, muscles, spleen, fluid accumulated in the pleural cavity do not produce any sound on percussion, what we hear is only a strike of the hammer on the plessimeter.



The pitch of the sound directly depends on the tissue density. The greater is the density, the higher is the frequency of vibrations, and the higher is the pitch.

Duration of the sound is in reverse dependence with the density of the tissue. The greater is the density, the higher is vibration frequency, the lower is the amplitude. Duration of the sound also decreases.

The percussion sound produced on investigation of a high-density tissue (inflammatory infiltration in the lung tissue, lung tumor) becomes shorter.

In spite of the fact that tissue of different structure participate in percussion and the produced sound is regarded a murmur, the pitch of the main sound can be distinguished. Speaking about the tone of the sound we mean the presence of the main sound. This sound is produced when the investigated tissue contains air. It is the mass of the vibrating air that is the source of the sound though the percussion also moves the adjacent tissues which are of different structure.

Three sounds clear (pulmonary), dull (deadened) and tympanic can be heard on percussion.

The character of percussion sounds. Clear lung sound is heard on percussion of the chest areas over an unchanged lung tissue. A clear sound is heard when the amount of air in the lungs, the tension of the lung tissue, and the thickness of the covering structures are normal. A clear lung sound is loud, long, low-pitched and not tympanic. It changes its properties depending on a number of conditions: the properties of the chest, development of the muscles, the amount of subcutaneous fat.

Dull sound is heard in the areas neighboring with dense parenchymatous organs (heart, liver, spleen). This sound is silent, short, high-pitched, resembles the sound produced by tapping on the wood.

Tympanic resonance is produced in the areas neighboring with the air-filled cavities. Tympanic resonance has a musical shade which occurs at beating a drum. In a healthy person, tympanic resonance is heard only in one area of the chest, on the left lower anterior portion, so-called Traube's semilunar space. The upper border of this space is limited by the lower edge of the liver, to the left - spleen, below - costal arch. In this area, the thoracic wall adjoins the fundus of the stomach with an air sac, which is the cause of the tympanic resonance in this area.

The rules of the percussion. To obtain clear percussion sound it is necessary to observe the following rules:

1. The middle or the point finger of the left hand plays the role of the plessimeter.

2. The percussion taps are made with a soft portion of the end phalanx of the right-hand middle finger on the middle phalanges of the plessimeter finger.

3. The hands of the physician should be warm not to produce unpleasant sensations.

4. The plessimeter finger is applied to the patient's body tightly but without excessive pressure. When the pressure is strong, even a weak percussion tap gets the properties of a strong one, which is not desired because its effect propagates to the depth and around the studied point. The point and the ring fingers should be kept apart, sliding apart the skin of the patient.

5. The axis of the end phalanx of the tapping finger as well as the direction of the percussion strike should be strictly perpendicular to the surface of the plessimeter finger. Onlyin this case the force of the percussion strike will be used to penetrate deep inside, not around the studied place.

6. Percussion strike should be light and always of the same force. It is necessary to learn to bend the hand only in the radioulnar joint, without moving the arm on tapping.

7. Percussion strike should be short and elastic.

8. Percussion of the lungs should be performed in an upright position, when the patient stands or sits.

9. The examination room should be warm.

Comparative and topographic percussion are distinguished. Topographic percussion is used to determine the lower border of the lungs, their mobility, the height of the lung apices and the width of Kronig's fields.

Comparative percussion allows to evaluate the morphological state of the underlying tissue considering the changes in the character of the sound.

Chest points and lines

To designate the location of the revealed normal or pathological findings it is convenient to use vertical (ordinates) and horizontal (abscissas) lines. The ribs can play the role of abscissas, the vertical lines drown through the definite points on the chest can serve as ordinates.

These lines are as follows:

1. Anterior median line (I. mediana) going vertically through the middle of the chest.

2. Right and left sternal lines (/. sternalis dextra at sinistra) going along the both edges of the breastbone.

3. Right and left parasternal lines (I. parasternalis dextra et sinistra) going vertically between the two above mentioned.

4. Right and left medioclavicular lines (I. medioclavuculare dextra at sinistra) going through the middle of the both collarbones.

5. Right and left anterior axillary lines (I. axillare dextra et sinistra) going through the anterior edges of the armpits.

6. Right and left middle axillary lines (I. axillare dextra et sinistra) going vertically through the middle of the both armpits.

7. Right and left posterior axillary lines (I. axillare posterior dextra et sinistra) going vertically through the posterior edges of the armpits.

8. Right and left scapular lines (7. scapulare dextra et sinistra) going vertically through the angles of the shoulder blades.

9. Right and left paravertebral lines (7. paravertebral dextra et sinistra) going vertically between the scapular lines and the line going through the processes of the vertebrae.

As these lines go through easily recognizable points they can be determined mentally. If a change is noticed not in the place of crossing the rib and one of the lines, the distance to the nearest line in centimeters is determined. The ribs are easily counted beginning from the second rib on the front, its cartilage is attached to the breastbone at the level of the so-called angulus Ludovici (the angle between the manubrium of sternum and its body). The rib of this angle is easily detected when drawing a line with a finger downward along the breastbone. It is frequently seen like a roller in the upper portion of the sternum. It is also easy to find the 7 rib as this is the last rib attached to the sternum with its cartilage. Vertebral processes are used to orient on the back, the process of the 7th cervical vertebra is felt as it is prominent when the head is bend forward. If three vertebrae are prominent together, the middle one is the 7th cervical vertebra. Besides, the orienting points can be clavicles, the axis of the shoulder blade, is lower angle, xiphoid process as well as fossae on the chest (supra-and subclavicular).

Percussion allows answering two important questions:

1. What changes has occurred in the studied organ?

2. What are the borders, size, and shape of the organ. The answer to the first question is obtained at the so-called comparative percussion, topographic percussion answers the second question.

Comparative percussion of the lungs

Comparative percussion of the lungs allows determining the presence of pathological changes judging by the changes in the character of the percussion sound. The obtained percussion sound is compared with normal sounds.

Comparative percussion should be done thoroughly satisfying the following conditions:

1. The percussion should be done in symmetrical areas of the chest.

2. The percussion should be started from the healthy side if the physician can suggest the location of the pathological process.

3. The position of the plessimeter finger and the force with which it is applied should be equal on the symmetrical sides of the chest.

4. The loudness of the sound depends of the force of percussion strike. The taps should be made with equal energy. It is necessary to remember that a moderate tap reaches the depth of 5 cm. It is recommended to use alternatively both weak and strong percussion to avoid mistakes: weak percussion may fail to reveal a deep affection, while strong percussion superficial.

5. Percussion should be done when the patient is maximally relaxed.

A number of factors (age, sex, structure of the chest), which can influence the findings, should be considered.

Even with the same energy of the strike the percussion sounds in a healthy person may be different over various areas of the chest. In the areas where the muscles or fat layer are more developed, the sound seems more silent; dull (the area of the shoulder blade, breast in women). In contrast, in children and adults with a thin chest the sound can be loud.

The loudness of percussion sound changes at breathing in and out. On deep respiration, two factors influence the loudness of percussion sound: increase of the amount of air in the studied area makes the sound louder, greater tension of the alveolar walls decreases the loudness of the sound. A reverse process takes place at deep breathing out. Therefore, the patient should breathe calmly when comparative percussion is done.

The ability of the bone tissue to conduct vibrations is greater, proper vibrations of the ribs join to the percussion sound when the ribs are stricken. Therefore, percussion should be done along the intercostal spaces.

It is necessary to bare in mind the effect of percussion sphere. On percussion the vibrations propagate not only in depth but also aside the studied area. The harder is the strike, the deeper are structures it reaches, and the greater is the degree of it lateral propagation (so-called percussion sphere), which should be avoided on percussion.

Technique of comparative percussion Comparative percussion is performed in the following order: 1) apices; 2) anterior surface of the lungs: along the intercostal spaces; 3) lateral surfaces: along the axillary lines; 4) posterior surface: along the scapular lines over the shoulder and above the angle of the scapula in the interscapular space. The following should be remembered:

1) percussion sound over the right apex is a little shorter due to its lower position when compared with the left one and more pronounced development of the muscles of the right shoulder girdle;

2) in the 2nd and 3rd intercostal spaces the percussion sound is shorter due to proximity of the heart;

3) percussion sound in the right axillary area is shorter due to the liver; on the left it is loud with tympanic shade due to proximity of a gas sac, i.e.the stomach (Traube's space).

A clear lung sound can become dull or tympanic.

Dullness of percussion sound is caused by reduction in the amount of air in the lung tissue, filling the pleural cavity with fluid, thickening of the pleura.

Reduction in the amount of air in the lung tissue and dullness of percussion sound are observed in pneumosclerosis, fibrous focal pulmonary tuberculosis, hepatization stage of lobular pneumonia, formation of a large cavity filled with inflammatory fluid (lung abscess, echinococcus cyst), foreign air-free tissue (tumor), in lung infarction (filling the alveoli with blood), complete atelectasis (collapse of the lung resulting from obstruction of the lumen or its compression).

At presence of small infiltrated air-free foci located between large areas of an unchanged lung tissue lying far from the surface, percussion sound can be clear. The larger are the air-free infiltrates, the closer they are located to the surface, the larger is their number, the less is the number of the areas of normal tissue between them, the more intensive is dullness. Percussion sound may become completely dull if a large air-free infiltrated area adjoins the studied area.

Changes in the pleura is another cause of dullness, which impedes percussion conduction to the air-containing tissue. Dullness can be observed in pleura thickening, tumors, presence of fluid in the pleural cavity (hydrothorax, pyothorax, hemothorax, exudation pleuritis). If the layer of the fluid is thick enough (>6 cm), the sound becomes dull. When effusion develops in the left pleural cavity and fills the left pleural sinus, tympanic resonance over Traube's space disappears. First signs of dullness occur when about 400 ml of fluid have accumulated in the lungs. But slight percussion sometimes allows determining the presence of even smaller amounts.

The upper level of dullness at moderate accumulation of the inflammatory exudate in the pleural cavity resembles a parabola, so-called Ellis-Damuaso line. The lowest point of this line is situated behind the vertebral column; from this point the line goes in an arch-like manner to the level of the scapula angle, further it goes down but at the level of the middle of the axillary area it goes up again and then down to the lowest point near the sternum. The cause of this arch-like pattern of the dullness level is different pliability of various areas of the lung to the accumulating fluid. The upper level of dullness will be higher in the areas where pliability is greater. In exudative pleurisy both layers of the pleura adhere at the upper level of the fluid due to sticky character of the exudate. That is why dullness outlines and Ellis-Damuaso line do not change when the patient's position changes.

As the posterior portions of the lungs are easier compresses than the anterior ones, the accumulating fluid first occupies the posterior departments of the pleural cavity and dullness is first noted posteriorly. When the upper level of the fluid reaches the middle of the scapula, the posterior portions of the lung become compressed that and their pliability does not exceed that of the anterior portions. From this moment the accumulating fluid starts occupying the anterior portions, dullness is noted in the anterior portions. The difference in compression of separate areas of the posterior portions is balanced at accumulation of large amounts of fluid, because pliability of the most heavily compressed areas decreased with the compression progression. Therefore, the upper level of dulness in the form of Ellis-Damuaso line is usually observed only when the amount of the exudate is moderate. When large amounts of exudate accumulate in the pleural cavity, the dullness occupies the whole half of the chest, the characteristic direction of its upper level (Ellis-Damuaso line) disappears.

In some cases dullness can be observed both anteriorly and posteriorly or only anteriorly even when the amount of fluid is moderate. This can be explained by the presence of adhesions between the visceral and pleural layers of the pleura, which do not allow the fluid to occupy the posterior portions. On the same reason, the upper level can have other then Ellis-Damuaso outlines in moderate exudation. The location of such exudation, called sacculated, may depend on the adhesion location in any area of the pleural cavity, hence the location of dullness may be different.

In exudation pleurisy a triangle space with dullness of the sound can be determined on the healthy side of the chest behind and lower the spinal column. This right-angle triangle is called Rauchfuss' triangle. Its hypotenuse is continuation of Ellis-Damuaso line on the healthy side of the chest, one side is the vertebral column, the other lower border of the lung. The cause of dullness in this triangle is displacement of the mediastinum organs to the healthy side.

When fluid (hydrothorax) or blood (hemothorax) accumulate in the pleural cavity, the upper level of dullness with moderate amount of fluid follows Ellis-Damuaso line. But, in contrast to exudation, this level changes with the changes in the patient's position (it changes slowly, within 1/41/2 hour) because with the absence of inflammation adhesions do not develop.

Tympanic character of the sound is observed at increased amount of air or decreased elasticity of the lung tissue. This may be observed at fluid accumulation in the pleural cavity (pneumothorax), at presence of an air-filled cavity (lung abscess, tuberculosis), when the cavity is large enough (>34 cm) and located close to the chest wall. If he cavity is large (> 6 cm), located superficially, and has smooth walls, low tympanic resonance resembling knocking at a metallic vessel is produced(bell tympanic sound). Bell sound is also heard over pneumothorax.

If a large cavity in the lungs is close to the chest and joints with the bronchus by a narrow opening, or in pneumothorax joined with the bronchus, a variety of tympanic resonance, high jingling sound, is heard. It develops with exit of the air in several portions through one opening.

In pulmonary emphysema percussion sound is low tympanic due to increased filling with air and decreased elastic tension of the lung tissue. This sound is termed vesiculotympanic (bandbox) resonance.

Combination of decreased clearness of the sound (dullness) and indistinct tympanic timber, dull tympanic sound, can sometimes be heard. It appears if at partially decreased filling with air the normal elastic tension of the lung tissue decreases. This develops in:

1) onset and resolution of lobular pneumonia, when the pulmonary tissue relaxes with incomplete infiltration;

2) in bronchopneumonia, if the foci of lung consolidation alternate with air-containing areas;

3) in effusive pleurisy, in the area located over the exudate where the lung tissue is poorly filled with air and looses its tension due to compression with fluid (obturation atelectasis);

4) in incomplete obturation atelectasis, in incomplete obstruction of bronchioles with sputum, pus, blood, tumor, when the pulmonary tissue tension decreases due to reduction of air amount in the alveoli;

5) in partial compression of the lung (compression atelectasis) with a tumor, highly located diaphragm, pneumothorax, fluid in the pleural cavity;

6) when the alveoli are filled with air and fluid in lung edema, lung infarction.

Besides, deadened tympanic sound can appear over large air-free areas of the lungs in acute infiltration if a strong percussion tap reaches deeply located large bronchi or cavities (caverns, abscesses) and causes vibration of the air in them.

 

Pathological changes of percussion sound

 

Incomplete or complete (in some cases) dullness a) decreased air content in the alveoli b) fluid or solid formation in the pleural cavity Lung infiltration (pneumonia, tuberculosis), atelectasis, tumor; Effusive pleurisy, adhesions of the pleural tumor
Tympani resonance a) a large cavity in the lung b) air in the pleural cavity Cavern, abscess; pneumothorax
Vesicular tympanic resonance (bandbox sound) Reduction of tissue elastic tension at increased air content Pulmonary emphysema
Deadened tympanic sound a) reduction of elastic tissue strain at decreased air content b) air-free areas with deep cavities Initial or final stage of pneumonia, partial atelectasis, pulmonary edema; cavern, lung abscess

 


Date: 2015-12-18; view: 955


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