ANATOMO-PHYSIOLOGICAL PECULIARITIES OF THE RESPIRATORY SYSTEM. PERCUSSION OF THE LUNGS

ANATOMO-PHYSIOLOGICAL PECULIARITIES OF THE RESPIRATORY SYSTEM. PERCUSSION OF THE LUNGS

 

Respiratory system in the newborn

 

The respiratory tract consists of a complex of structures that function under neural and hormonal control. At birth the respiratory system is relatively small, but after the first breath the lungs grow rapidly. The shape of the chest changes gradually from a relatively round configuration at birth to one that is more or less flattened in the anteroposterior diameter in adulthood. In severe obstructive lung disease the anteroposterior measurement approaches the transverse measurement. Periodic measurements provide clues to the course of lung disease or the efficacy of therapy.

Changes take place in the air passages that increase respiratory surface area. For example, during the first year the alveoli in the terminal units rapidly increase iumber. In addition, the early globular alveoli develop septa that causes them to become more lobular. They continue to increase steadily until, at the age of 12 years, there are approximately nine times as many as were present at birth. In later stages of growth the structures lengthen and enlarge.

After the early weeks of life the respiratory tract follows the general growth curve. However, the respiratory apparatus grows faster than the vertebral column, resulting in alterations in the relationships between these structures. The bifurcation of the trachea lies opposite the third thoracic vertebra in the infant and gradually descends to a position opposite the fourth vertebra in the adult; the cricoid cartilage descends from the level of the fourth cervical vertebra in the infant to that of the sixth in the adult. These anatomic changes produce differences in the angle of access to the trachea at various ages and must be considered when the infant or child is to be positioned for purposes of resuscitation and airway clearance. The larynx grows slowly until puberty, when its accelerated growth produces changes in the voice that are particularly marked in boys.

Respiratory movements are first evident at approximately 20 weeks gestation, and throughout fetal life there is an exchange of amniotic fluid in the alveoli. In the neonate the respiratory rate is rapid to meet the needs of a high metabolism. During growth, the rate steadily decreases in both boys and girls until it levels off at maturity. The volume of air inhaled increases with the growth of the lungs and is closely related to the body size. In addition, there is a qualitative difference in expired air at different ages. The amount of oxygen in the expired air gradually decreases and the amount of carbon dioxide increases during growth. Other important aspects of the respiratory function are discussed as they relate to prenatal life and perinatal adjustments, the newborn infant, and acute and chronic respiratory problems of infants and children.

 

Physiologicoanatomical peculiarities of the respiratory system

The peculiarities of the nose at the neonate

a) The nose consists particular by of cartilage,

b) The nasal meatuses are narrow,

c) There are not inferior nasal meatuses (until 4 years),

d) Undeveloped submucosal membrane (until 8-9 years).

  

The peculiarities of sinuses in children

a) The maxillary sinus is usually present at birth,

b) The frontal sinuses begin to develop in early infancy,

c) The ethmoid and sphenoid sinuses develop later in childhood.

 

The peculiarities of the pharynx at the neonate

a) The pharynx is relatively small and narrow,

b) The auditory tubes are small, wide, straight and horizontal.

 

 The peculiarities of the larynx at the neonate

a) The larynx is funnel-shaped (in the adult it is relatively round),

b) It is relatively long,

c) The cricoid’s cartilage descendents from the level of the fourth cervical vertebra in the infant to that of the sixth in the adult,

d) The fissure of glottis is narrow and its muscles fatigue soon,

e) Vocal ligaments and mucous membrane are very tender, are well blood-supplied,

f)  Vocal ligament are relatively short.

 

The peculiarities of the trachea at the neonate

a) The length of the trachea is relatively larger (about 4 cm (in the adult -7)) and wide,

b) It is composed of 15-17 cartilage rings (the amount does not increase),

c) The bifurcation of the trachea lies opposite the third thoracic vertebra in infant and descends to a position opposite the fourth vertebra in the adult,

d) Mucus membrane is soft, well-blood supplied, but sometime dry,

f) It can collapse easily.

 

The peculiarities of the bronchi at the neonate

a) In young children the bronchi are relatively wide,

b) The right bronchus is a straight continuation of the trachea,

c) The muscle and elastic fibers are undeveloped,

d) The bronchi are well blood supplied,

e) The lobules and segmental bronchus are narrow.

 

The functions of the bronchus

a) The ciliated of mucus membrane “sweeps” out dust particles,

b) Transfer the gases into the lungs,

c) Immunologic function.

 

The functions of the lung are:

a) The main function of the lungs is the exchange of oxygen and carbon dioxide,

b) To produce surfactant

 

The peculiarities of the lungs at the neonate:

a) Size of alveoli is smaller than in the adult;

b) Quantity of alveoli is relatively less than in the adult.

 

Examination of the chest in children

Body symmetry is always an important notation during the inspection of the chest. Asymmetry in the chest may indicate serious underlying problems, such as cardiac enlargement (bulging on the left side of the rib cage) or pulmonary dysfunction. However, asymmetry is most often a sign of scoliosis, lateral curvature of the spine. Asymmetry requires further medical investigation.

Movement of the chest wall is noted. It should be symmetric bilaterally and coordinated with breathing. During inspiration the chest rises and expands, the diaphragm descends, and the costal angle increases. During expiration the chest falls and decreases in size, the diaphragm rises, and the costal angle narrows. In children under 6 or 7 years of age, respiratory movement is principally abdominal or diaphragmatic. In older children, particularly females, respirations are chiefly thoracic. In either type the chest and abdomen should rise and fall together.

Any asymmetry of movement is an important pathologyc sign and is reported. Decreased movement on one side of the chest may indicate pneumonia, pneumothorax, atelectasis, or an obstructive foreign body. Marked retraction of muscles either between the ribs (intercostal), above the sternum (suprasternal), or above the clavicles (supraclavicular) is always noted, because it is a sign of respiratory difficulty.

 

Examination of the lungs in children

 

The lungs are situated inside the thoracic cavity, with one lung on each side of the sternum. Each lung is divided into an apex, which is slightly pointed and rises above the first rib, a base, which is wide and concave and lies on the domeshaped diaphragm, and a body, which is divided into lobes.

The right lung has three lobes: upper, middle, and lower. The left lobe has only two lobes, upper and lower, because of the space occupied by the heart. The two surfaces of the lungs are the costal surface, which faces the chest wall and backs up to the vertebral column, and the mediastinal surface, which faces the space lying between the lungs, the mediastinum. The center of the mediastinal surface is called the hilust where the bronchus and blood vessels enter the lung.

Examination of the lungs requires knowledge of their location and their relationship to the rib cage. The trachea bifurcates slightly below the level of the sternal angle. The lower costal margin crosses the sixth rib at the midclavicular line and the eighth rib at the midaxillary line. The posterior base of the lungs crosses the eleventh rib at the vertebral line. The upper border of the right middle lobe parallels the inferior surface of the fourth rib. Respiration causes displacement of the lobes upward (expiration) or downward (inspiration).

Inspection. Inspection of the lungs involves primarily observation of respiratory movements, which are discussed. Respirations are evaluated for (1) rate (number per minute), (2) rhythm (regular, irregular, or periodic), (3) depth (deep or shallow), and (4) quality (effortless, automatic, difficult, or labored). The doctor also notes the character of breath sounds based on inspection without the aid of auscultation, such as noisy, grunting, snoring, or heavy.

 

An average respiratory rate at rest of the child of different age is:

 

 

The respiratory rate is always evaluated in relation to general physical status. For example, tachypnea is expected with fever, because for every degree Fahrenheit elevation in temperature, the respiratory rate increases 4 breaths per minute. The usual ratio of breaths to heartbeats is 1:4.

 

Disorders of the respiratory rate

          Tachypnea is the increase of the respiratory rate.

          Bradypnea is the decrease of the respiratory rate.

          Dyspnea is the distress during breathing.

          Apnea is the cessation of breathing.

 

Disorders of the respiratory depth

          Hyperpnea is an increased depth.

          Hypoventilation is a decreased depth and irregular rhythm.

          Hyperventilation is an increased rate and depth.

 

Pathological respiration

Seesaw (paradoxic) respirations:  the chest falls on inspiration and rises on expiration. It is usually observed in respiratory failure of third degree;

 

Kussmaul breathing is a deep and labored breathing pattern often associated with severe metabolic acidosis, particularly diabetic ketoacidosis (DKA) but also renal failure. It is a form of hyperventilation, which is any breathing pattern that reduces carbon dioxide in the blood due to increased rate or depth of respiration.

In metabolic acidosis, breathing is first rapid and shallow but as acidosis worsens, breathing gradually becomes deep, labored and gasping. It is this latter type of breathing pattern that is referred to as Kussmaul breathing.

Kussmaul breathing is respiratory compensation for a metabolic acidosis, most commonly occurring in diabetics in diabetic ketoacidosis. Blood gases on a patient with Kussmaul breathing will show a low partial pressure of CO₂ in conjunction with low bicarbonate because of a forced increased respiration (blowing off the carbon dioxide). Base excess is severely negative. The patient feels an urge to breathe deeply, an “air hunger”, and it appears almost involuntary.

A metabolic acidosis soon produces hyperventilation, but at first it will tend to be rapid and relatively shallow. Kussmaul breathing develops as the acidosis grows more severe. Indeed, Kussmaul originally identified this type of breathing as a sign of coma and imminent death in diabetic patients.

Duration of fasting, presence or absence of hepatomegaly and Kussmaul breathing provide clues to the differential diagnosis of hyperglycemia in the inborn errors of metabolism

 

Cheyne–Stokes respiration is an abnormal pattern of breathing characterized by progressively deeper and sometimes faster breathing, followed by a gradual decrease that results in a temporary stop in breathing called an apnea. The pattern repeats, with each cycle usually taking 30 seconds to 2 minutes. It is an oscillation of ventilation between apnea and hyperpnea with a crescendo-diminuendo pattern, and is associated with changing serum partial pressures of oxygen and carbon dioxide.

Cheyne–Stokes respiration and periodic breathing are the two regions on a spectrum of severity of oscillatory tidal volume. The distinction lies in what is observed at the trough of ventilation: Cheyne–Stokes respiration involves apnea (since apnea is a prominent feature in their original description) while periodic breathing involves hypopnea (abnormally small but not absent breaths).

These phenomena can occur during wakefulness or during sleep, where they are called the central sleep apnea syndrome (CSAS).

It may be caused by damage to respiratory centers, or by physiological abnormalities in chronic heart failure, and is also seen iewborns with immature respiratory systems and in visitors new to high altitudes.

 

Biot’s respiration, sometimes also called ataxic respiration, is an abnormal pattern of breathing characterized by groups of quick, shallow inspirations followed by regular or irregular periods of apnea.

It generally indicates a poor prognosis. Biot’s respiration is caused by damage to the medulla oblongata due to strokes or trauma or by pressure on the medulla due to uncal or tentorial herniation.

It can be caused by opioid use. Related patterns It is distinguished from ataxic respiration by having more regularity and similar-sized inspirations, whereas ataxic respirations are characterized by completely irregular breaths and pauses. As the breathing pattern deteriorates, it merges with ataxic respirations.

In common medical practice, Biot’s respiration is often clinically equivalent to Cheyne-Stokes respiration, although the two definitions are separated in some academic settings.

 

Palpation

Respiratory movements are felt by placing each hand flat against the back or chest with the thumbs in midline along the lower costal margin of the lungs. The child should be sitting during this procedure and, if cooperative, should take several deep breaths. During respiration the hands will move with the chest wall. The doctor evaluates the amount and speed of respiratory excursion, noting any asymmetry of movement. Normally in older children the posterior base of the lungs descends 5 to 6 cm (about 2 inches) during a deep inspiration.

          The doctor also palpates for vocal fremitus, the conduction of voice sounds through the respiratory tract. With the palmar surfaces of each hand on the chest, the doctor asks the child to repeat words, such as “ninety-nine”, “one, two, three,” “eee-eee” or “тридцять три”. The child should speak the words with a voice of uniform intensity. Vibrations are felt as the hands move symmetrically on either side of the sternum and vertebral column. In general vocal fremitus is the most intense in the regions of the thorax where the trachea and bronchi are the closest to the surface, particularly along the sternum between the first and second ribs and posteriorly between the scapulae. Progressing downward, the sound decreases and is least prominent at the base of the lungs.

 

Decreased vocal fremitus in the upper airway may indicate

a) the obstruction of a major bronchus,

b) pneumo-, hydro-, haemothorax,

c) emphysema of lungs,

d) adiposity can also be the cause of decreased vocal fremitus.

 

The voice of fremitus is increased

a) in pneumonia,

b) in abscess,

b) in atelectasis,

c) in cavern.

 

Absence of fremitus usually indicates obstruction of a major bronchus, which may occur as the result of aspiration of a foreign body.

Decreased or absent fremitus is always recorded and reported for further investigation. During palpation other vibrations that indicate pathologic conditions are noted. One is a pleural friction rub, which has a grating sensation. It is synchronous with respiratory movements and is the result of opposing surfaces of the inflamed pleural lining rubbing against one another,

Crepitation is felt as a coarse, cracking sensation as the hand presses over the affected area. It is the result of the escape of air from the lungs into the subcutaneous tissues from an injury or surgical intervention. Both pleural friction rubs and crepitation can usually be heard as well as felt.

 

Percussion. The lungs are percussed in order to evaluate the densities of the underlying organs. Resonance is heard over all the lobes of the lungs that are not adjacent to other organs. Dullness is heard beginning at the fifth interspace in the right midclavicular line. Percussing downward to the end of the liver, a flat sound is heard because the liver no longer overlies the air-filled lung. Cardiac dullness is felt over the left sternal border from the second to the fifth interspace medially to the midclavicular line. Below the fifth interspace on the left side, tympany results from the air-filled stomach. Deviations from these expected sounds are always recorded and reported.

In comparative percussing the chest, the anterior lung is percussed from apex to base, usually with the child in the supine or sitting position. Each side of the chest is percussed in sequence in order to compare the sounds, such as the dullness of the liver on the right side with the tympany of the stomach on the left side. When percussing the posterior lung, the procedure and sequence are the same, although the child should be sitting. Normally only resonance is heard when percussing the posterior thorax from the shoulder to the eighth or tenth rib. At the base of the lungs dullness is heard as the diaphragm is percussed.

 

The pathological dullness is heard in cause of

a)                 pneumonia,

b)                hydro-, haemothorax,

c)                 pulmonary edema,

d)                lung or mediastinal tumor.

 

The banbox is heard in cause of

a)                 emphysema of lungs,

b)                cavern of lung,

c)                 abscess of lung,

d)                pneumothorax,

e)                 bronchial asthma,

f)                  asthmatic bronchitis.

In topographic percussing the chest, the doctor looks for the lungs’ borders in the main lines, the location of the apex of the lung and width of Crenig’s areas. The topographic percussion is used only in children older 7 years old.

In topographic percussion the margin of the lung is assessed from the side of resonance sound.

         The location of the lower costal margin of the lungs is shown in Table

 

The lower costal margin of the lungs according the age of the child

 

         

The upper margin of the lung (the location of the apex of the lung) is determined by percussions from the clavicle to the neck. The apex of each lung rises about 2 to 4 cm above the inner third of the clavicles in front of the body At the back we examine the location of the apex of the lung by percussions from the scapula axis to the seventh cervical vertebra. Normally, the upper border of the lung is in the seventh cervical vertebra at the back.

          The width of Crenig’s areas is determined by percussions from the middle of muscle trapezium to each direction (to neck and shoulder) to disappearance of the resonance. Normally, the width of Crenig’s areas is 3-5 cm.

The excursion of the lung is the distance between the lower costal margin of the lungs in the maximum inspiration and maximum expirations. Normally, the excursion of the lung is 2-6 cm.

 

Auscultation. Auscultation involves using the stethoscope to evaluate breath and voice sounds. Breath sounds are best heard if the child inspires deeply. The child can be encouraged to “take a big breath” by following a demonstration of “breathing in through the nose and out through the mouth.” Younger children respond well to games such as blowing out the light from a cigarette lighter or the light of the otoscope.

In the lungs breath sounds are classified as vesicular or bronchovesicular. Vesicular breath sounds are normally heard over the entire surface of the lungs, with the exception of the upper intrascapular area and the area beneath the manubrium. Inspiration is louder, longer, and higher-pitched than expiration. Sometimes the expiratory phase seems nearly absent in comparison to the long inspiratory phase. The sound is a soft, swishing noise.

 

Bronchovesicular breath sounds are normally heard over the manubrium and in the upper intrascapular regions where there are bifurcations of large airways, such as the trachea and bronchi. Inspiration is louder and higher in pitch than that heard in vesicular breathing.

 

Puerile breath sounds are one of normal types of breathing in children by three years old. Puerile breath sounds have shot inspiration and louder, a hollow expiratory phase, blowing character.

Another type of breathing that is normal only over the trachea near the suprasternal notch is bronchial breath sounds. They are almost the reverse of vesicular sounds; the inspiratory phase is short and the expiratory phase is longer, louder, and of higher pitch. They are usually louder than any of the normal breath sounds and have a hollow, blowing character

Bronchial breathing anywhere in the lungs except over the trachea denotes some abnormality, such as consolidation or compression of the lung tissue (pneumonia, tbc).

 

Rough breath sounds have shot inspiration and louder expiratory phase. Rough breath has hollow and blowing character. The diagram of rough breath sounds is:

 

Absent or diminished breath sounds are always an abnormal finding warranting investigation. Fluid, air, or solid masses in the pleural space all interfere with the conduction of breath sounds (pneumonia, pneumo-, hydro-, haemothorax, tumor of lung or mediastinal, emphysema of lungs, atelectasis, airways obstruction, a foreing body in the bronchus). Diminished breath sounds in certain segments of the lung can alert the doctor to pulmonary areas that may benefit from postural drainage and percussion. Increased breath sounds following pulmonary therapy indicate improved passage of air through the respiratory tract.

Voice sounds are also part of auscultation of the lungs. Normally voice sounds or vocal resonance is heard, but the syllables are indistinct. They are elicited in the same manner as vocal fremitus, except that the doctor listens with the stethoscope. Consolidation of the lung tissue produces three types of abnormal voice sounds.

1. Whispered pectoriloquy, in which the child whispers words and the nurse, hears the syllables.

2.  Bronchophony, in which the child speaks words that are not distinguishable but the vocal resonance is increased in intensity and clarity.

3.  Egophony, in which the child says “ee,” which is heard as the nasal sound “ay” through the stethoscope.

Decreased or absent vocal resonance is caused by the same conditions that affect vocal fremitus.

 

 

Auscultation is perhaps the most important and effective clinical technique you will ever learn for evaluating a patient’s respiratory function. Before you begin, there are certain things that you should keep in mind:

          a) It is important that you try to create a quiet environment as much as possible. This may be difficult in a busy emergency room or in a room with other patients and their visitors.

 

Eliminate noise by closing the door and turning off any radios or televisions in the room.

          b) The patient should be in the proper position for auscultation, i.e. sitting up in bed or on the examining table, ensuring that his or her chest is not leaning against anything. If this is not possible, ask for assistance or perform only a partial assessment of the patient’s breathing.

          c) Your stethoscope should be touching the patient’s bare skin whenever possible or you may hear rubbing of the patient’s clothes against the stethoscope and misinterpret them as abnormal sounds. You may wish to wet the patient’s chest hair with a little warm water to decrease the sounds caused by friction of hair against the stethoscope.

          d) Always ensure patient comfort. Be considerate and warm the diaphragm of your stethoscope with your hand before auscultation.

 

As you are auscultating your patient, please keep in mind these 2 questions:

1) Are the breath sounds increased, normal, or decreased?

2) Are there any abnormal or adventitious breath sounds?

 

To assess the posterior chest, ask the patient to keep both arms crossed in front of his/her chest, if possible.

Auscultate using the diaphragm of your stethoscope. Ask the patient not to speak and to breathe deeply through the mouth. Be careful that the patient does not hyperventilate. You should listen to at least one full breath in each location. It is important that you always compare what you hear with the opposite side. e.g. If you are listening to the left apex, you should follow through by comparing what you heard with what you hear at the right apex.

There are between 12 and 14 locations for auscultation on the anterior and posterior chest respectively. Generally, you should listen to at least 6 locations on both the anterior and posterior chest. Begin by ausculating the apices of the lungs, moving from side to side and comparing as you approach the bases. Making the order of the numbers in the images below a ritual part of your pulmonary exam is a way of ensuring that you compare both sides every time and you’ll begin to know what each area should sound like under normal circumstances.

If you hear a suspicious breath sound, listen to a few other nearby locations and try to delineate its extent and character.

There are between 12 and 14 locations for auscultation on the anterior and posterior chest respectively. Generally, you should listen to at least 6 locations on both the anterior and posterior chest. Begin by ausculating the apices of the lungs, moving from side to side and comparing as you approach the bases. Making the order of the numbers in the images below a ritual part of your pulmonary exam is a way of ensuring that you compare both sides every time and you’ll begin to know what each area should sound like under normal circumstances.

          If you hear a suspicious breath sound, listen to a few other nearby locations and try to delineate its extent and character.

 

Breath Sounds

          Breath sounds can be divided and subdivided into the following categories:

          Normal

          Abnormal

          Adventitious

          tracheal

          absent/decreased

          crackles (rales)

          vesicular

          bronchial

          wheeze

          bronchial

          rhonchi

          bronchovesicular

          stridor

          pleural rub

          mediastinal crunch (Hamman’s sign)

 

Normal Breath Sounds

          These are traditionally organized into categories based on their intensity, pitch, location, and inspiratory to expiratory ratio. Breath sounds are created by turbulent air flow. In inspiration, air moves into progressively smaller airways with the alveoli as its final location. As air hits the walls of these airways, turbulence is created and produces sound. In expiration, air is moving in the opposite direction towards progressively larger airways. Less turbulence is created, thus normal expiratory breath sounds are quieter than inspiratory breath sounds.

          tracheal breath sound. Tracheal breath sounds are very loud and relatively high-pitched. The inspiratory and expiratory sounds are more or less equal in length. They can be heard over the trachea, which is not routinely auscultated.

          vesicular breath sound.  The vesicular breath sound is the major normal breath sound and is heard over most of the lungs. They sound soft and low-pitched. The inspiratory sounds are longer than the expiratory sounds. Vesicular breath sounds may be harsher and slightly longer if there is rapid deep ventilation (eg post-exercise) or in children who have thinner chest walls. As well, vesicular breath sounds may be softer if the patient is frail, elderly, obese, or very muscular.

          bronchial breath sound. Bronchial breath sounds are very loud, high-pitched and sound close to the stethoscope. There is a gap between the inspiratory and expiratory phases of respiration, and the expiratory sounds are longer than the inspiratory sounds. If these sounds are heard anywhere other than over the manubrium, it is usually an indication that an area of consolidation exists (ie space that usually contains air now contains fluid or solid lung tissue).

          bronchovesicular breath sound. These are breath sounds of intermediate intensity and pitch. The inspiratory and expiratory sounds are equal in length. They are best heard in the 1st and 2nd ICS (anterior chest) and between the scapulae (posterior chest) – ie over the mainstem bronchi. As with bronchial sounds, when these are heard anywhere other than over the mainstem bronchi, they usually indicate an area of consolidation.

 

Abnormal Breath Sounds

Absent or Decreased Breath Sounds. There are a number of common causes for abnormal breath sounds, including:

          • ARDS: decreased breath sounds in late stages

          • Asthma: decreased breath sounds

          • Atelectasis: If the bronchial obstruction persists, breath sounds are absent unless the atelectasis occurs in the RUL in which case adjacent tracheal sounds may be audible.

          • Emphysema: decreased breath sounds

          • Pleural Effusion: decreased or absent breath sounds. If the effusion is large, bronchial sounds may be heard.

          • Pneumothorax: decreased or absent breath sounds

Bronchial Breath Sounds in Abnormal Locations Bronchial breath sounds occur over consolidated areas.

 

Adventitious Breath Sounds

          Crackles (Rales) Crackles are discontinuous, non-musical, brief sounds heard more commonly on inspiration.

They can be classified as fine (high pitched, soft, very brief) or coarse (low pitched, louder, less brief). When listening to crackles, pay special attention to their loudness, pitch, duration, number, timing in the respiratory cycle, location, pattern from breath to breath, change after a cough or shift in position. Crackles may sometimes be normally heard at the anterior lung bases after a maximal expiration or after prolonged recumbency.

The mechanical basis of crackles: Small airways open during inspiration and collapse during expiration causing the crackling sounds. Another explanation for crackles is that air bubbles through secretions or incompletely closed airways during expiration.

Conditions:

          • ARDS

          • asthma

          • bronchiectasis

          • chronic bronchitis

          • consolidation

          • early CHF

          • interstitial lung disease

          • pulmonary oedema

 

 Adventitious Breath Sounds

Crackles (Rales) (tracks 13, 19 & 14) Crackles are discontinuous, non-musical, brief sounds heard more commonly on inspiration.

          They can be classified as fine (high pitched, soft, very brief) or coarse (low pitched, louder, less brief). When listening to crackles, pay special attention to their loudness, pitch, duration, number, timing in the respiratory cycle, location, pattern from breath to breath, change after a cough or shift in position. Crackles may sometimes be normally heard at the anterior lung bases after a maximal expiration or after prolonged recumbency.

          The mechanical basis of crackles: Small airways open during inspiration and collapse during expiration causing the crackling sounds. Another explanation for crackles is that air bubbles through secretions or incompletely closed airways during expiration.

          Conditions:

          • ARDS

          • asthma

          • bronchiectasis

          • chronic bronchitis

          • consolidation

          • early CHF

          • interstitial lung disease

          • pulmonary oedema

 

Wheeze

          Wheezes are continuous, high pitched, hissing sounds heard normally on expiration but also sometimes on inspiration. They are produced when air flows through airways narrowed by secretions, foreign bodies, or obstructive lesions.

          Note when the wheezes occur and if there is a change after a deep breath or cough. Also note if the wheezes are monophonic (suggesting obstruction of one airway) or polyphonic (suggesting generalized obstruction of airways).

          Conditions:

          • asthma

          • CHF

          • chronic bronchitis

          • COPD

          • pulmonary oedema

 

Rhonchi

          Rhonchi are low pitched, continuous, musical sounds that are similar to wheezes. They usually imply obstruction of a larger airway by secretions.

 

Stridor

          Stridor is an inspiratory musical wheeze heard loudest over the trachea during inspiration.

          Stridor suggests an obstructed trachea or larynx and therefore constitutes a medical emergency that requires immediate attention.

 

Pleural Rub

          Pleural rubs are creaking or brushing sounds produced when the pleural surfaces are inflamed or roughened and rub against each other. They may be discontinuous or continuous sounds.

          They can usually be localized a particular place on the chest wall and are heard during both the inspiratory and expiratory phases.

          Conditions:

          pleural effusion

          pneumothorax

 

Mediastinal Crunch (Hamman’s sign)

          Mediastinal crunches are crackles that are synchronized with the heart beat and not respiration. They are heard best with the patient in the left lateral decubitus postion. As with stridor, mediastinal crunches should be treated as medical emergencies.

          Conditions:

          pneumomediastinum

          Summary

 

Wheeze

          Wheezes are continuous, high pitched, hissing sounds heard normally on expiration but also sometimes on inspiration. They are produced when air flows through airways narrowed by secretions, foreign bodies, or obstructive lesions.

          Note when the wheezes occur and if there is a change after a deep breath or cough. Also note if the wheezes are monophonic (suggesting obstruction of one airway) or polyphonic (suggesting generalized obstruction of airways).

          Conditions:

          • asthma

          • CHF

          • chronic bronchitis

          • COPD

          • pulmonary oedema

 

 

Rhonchi

          Rhonchi are low pitched, continuous, musical sounds that are similar to wheezes. They usually imply obstruction of a larger airway by secretions.

 

Stridor

          Stridor is an inspiratory musical wheeze heard loudest over the trachea during inspiration.

          Stridor suggests an obstructed trachea or larynx and therefore constitutes a medical emergency that requires immediate attention.

 

Pleural Rub

          Pleural rubs are creaking or brushing sounds produced when the pleural surfaces are inflamed or roughened and rub against each other. They may be discontinuous or continuous sounds.

          They can usually be localized a particular place on the chest wall and are heard during both the inspiratory and expiratory phases.

          Conditions:

          pleural effusion

          pneumothorax

 

Mediastinal Crunch (Hamman’s sign)

          Mediastinal crunches are crackles that are synchronized with the heart beat and not respiration. They are heard best with the patient in the left lateral decubitus postion. As with stridor, mediastinal crunches should be treated as medical emergencies.

Conditions:

          pneumomediastinum

 

 

 

References

а) Basic

 

1. Manual of Propaedeutic Pediatrics / S.O. Nykytyuk, N.I. Balatska, N.B. Galyash, N.O. Lishchenko, O.Y. Nykytyuk – Ternopil: TSMU, 2005. – 468 pp.

2. Kapitan T. Propaedeutics of children’s diseases and nursing of the child : [Textbook for students of higher medical educational institutions] ; Fourth edition, updated and

    translated in English / T. Kapitan – Vinnitsa: The State Cartographical Factory, 2010. – 808 pp.

3. Nelson Textbook of Pediatrics /edited by Richard E. Behrman, Robert M. Kliegman; senior editor, Waldo E. Nelson – 19^th ed. – W.B.Saunders Company, 2011. – 2680 p.

 

b) Additional

1.  www.bookfinder.com/author/american-academy-of-pediatrics 

2. www.emedicine.medscape.com

3. http://www.nlm.nih.gov/medlineplus/medlineplus.html