RESPIRATORY SYSTEM
-
-
-
-
-
-
-
-
The chest wall in infants is more compliant than that of older children and adults.
For that reason, they are more prone for alveolar collapse and labored respiration [or increased work
of breathing (WOB)].
The complaint chest cage does not support the alveoli and tends to move inward instead of moving
outward during disease states which require more WOB.
This leads to the obvious retractions.
In adult, both the chest and the abdomen moves outward during inspiration, however, in infants and
even up to the age of 6 years, the chest tends to move inward, while the abdomen tends to move
outward.
This is called abdominal breathing.
Abdominal breathing is abnormal beyond the age of 6 years and indicates increased WOB or
significant respiratory distress[ RD].
Because of the higher compliance of the chest cage in infants, the infants who present with RD needs
the institution of the positive end expiratory pressure [PEEP] during conventional mechanical
ventilation [CMV] to prevent the alveoli from collapse during expiration.
The nose of the neonates and infants during the first few month of life is small and they are obligate
nasal breather. So, the obstruction of the nose, even during an episode of mild upper respiratory
tract infection [URTI], may cause a significant RD.
During infancy, almost 50 % of the airway resistance [Raw] to the airflow is caused by the nose alone.
The upper airway [UAW] of the infants and young children is smaller than that of older children and
adults, and minimal edema can cause severe upper airway obstruction [UAWO].
One millimeter [ mm] edema in an infant increases the Raw by, approximately, 16 fold, while it
causes, only, 4 folds increase in the Raw in adult.
The Raw is indirectly proportional to the 4th power of the radius [internal diameter (ID)] of the airway
 as the ID, the caliper or the radius of an airway increases, the Raw decreases and vice versa.
The UAW of the infants are more likely to be obstructed because of the relatively large tongue [the
tongue lies on the posterior pharynx when the infant is unconscious, when there is excessive
secretions and in Perre Rubbin Syndrome (because of small mandible)].
The UAW is difficult to access during direct laryngoscopy for endo-tracheal intubation [ETI] because
of the following factors; 1]- relatively large tongue; which may obscure the view during
laryngioscopy, 2]- floppy epiglottis [difficult to control], 3]- and amore cephald [high and anteriorly
located larynx]; which is more of a funnel shaped rather than cylindrical in comparison to adults
larynx. In addition it is form an acute angle with the view of vision during laryngioscopy.
Earlier studies suggested that infants lack airway smooth muscles similar to that in adults; which
implied that they are less prone to broncho-constriction and increased Raw. However, recent
evidences suggested that infants can exhibit reactivity to a certain stimuli and have B- receptors;
which also respond to B-agonist.
Pulmonary defense mechanisms, including cough, muco-cilliary clearance [MCC] and local and
circulating component of the immune system are present at birth, however, specific defects in
immunity may present over variable period after birth.
This time lapse, perhaps, reflects the passive immunity from the mother and the timing of infectious
challenges to the respiratory tract of infants.
-
-
-
-
-
-
The physical examination of the respiratory system in pediatrics is done to corroborate the findings
obtained from the history to assess the severity the illness, to assess the adequacy of the gas
exchange across the alveolar-capillary [AC] membrane and to localize the disease process.
The Traditional Approach of inspection, palpation, percussion and auscultation remains important,
though these techniques have their LIMITATION in newborns and small infants.
In small infants, a lot of valuable information can be gathered without touching the child.
At the beginning of physical examination, ALAWYS, remember that you should introduce yourself to
the caregiver or older child, make good rapport with them and explain what is going on.
By observing carefully the child, while he is on his mother lap, you can gather a lot of information;
which are contributory to the physical examination of the respiratory system [such as color (pink or
cyanotic), distressed or comfortable], you can count the respiratory rate [RR], notices the use of
accessory muscles of respiration, flaring of the ala nasi, grunting and the level of consciousness
[LOC].
You should observe weather, the patient is on mechanical ventilator or on oxygen [O2] therapy, If on,
ventilator, you need to mention the settings.
If he is on O2 therapy, you need to mention what is the oxygen delivery method [simple face mask,
nasal cannula or non re-breathing face mask with or without reservoir] and how much is the flow of
oxygen in liter per minute [L/m].
Observe the vital signs on the cardio-pulmonary monitor [tachycardia may be related to hypoxia,
congestive heart failure [CHF] as the cause of RD or the use of B- agonists].
Observe the saturation of hemoglobin by O2 as measured by the pulse oxymetry [SpO2].
The assessment of the RR and the depth of inspiration is critical.
Measure the respiratory rate [RR] over a full one minute.
Describe its depth and the characteristics of breathing [periodic, chyne stoke, any apnea or
hyperapnea during the course of one minute measurement].
Have a chance to look for the presence of peri-orbital edema [denoting CHF as the cause of RD] and
jugular venous engorgement [right heart failure and cor-pulmonale]. These 2 findings may not be
helpful in small infants.
Have a chance to look for finger and toes clubbing [chronic hypoxemia due to chronic suppurative
lung diseases] and look for evidence of pallor.
have a rough assessment of weather the infant is failing to thrive or not [indicating chronic illnesses]
and measure and plot the growth parameter at the end of the examination.
Before touching the baby, MAKE SURE that your hands are warm up to the elbow.
The best position for the patient examination depends on the age.
It is as the following; 1]- for neonates and small infants [the examination table], 2]- for toddler and
young children [when they are lying sitting on the mother lap], 3]- and for adolescents [without the
presence of their parents].
Wash your hands thoroughly before you touch any patient.
Be on the right side of the patient and try to be at his level [standing on your knees].
Expose as needed and minimize the time for exposure.
For smaller infants, the mother can help in undressing.
For adolescence, privacy is of paramount.
Start by exposing or asking the mother to expose the patient chest.
looks for cutery marks, scars, pulges and/or masses.
If you find any, describe its exact locations and dimensions].
-
-
-
-
-
-
If a scar is found, describe its exact location [such as lateral thoracotomy scar or mid-sternal scars]
and its length and age [fresh or healed].
If you find a cauterization marks, describe their exact location, number, length, healing status and
weather they are clean or infected.
Look for the respiratory movement pattern and the signs of increased WOB or RD [such as
intercostals retractions, sub-costal retractions, sterna retraction and supra-sternal retraction].
Look for the adequacy of the tidal volume generation [adequate chest expansion], evidences of
restricted movement of one side or evidence of shallow breathing].
Look for signs of hyper-inflation [such as pectus carinatum and pulging chest [increased anterioposterior diameter of the chest].
Look for signs of UAWO [sternal or supra-sternal recession] and at the same time listen if there is any
inspiratory abnormal noises [such as stridor or snoring].
The face shape [adenoid face; with opened mouth and prominent maxilla may be manifestations of
adenoid and significant tonisllar hypertrophy] causing UAWO.
Palpation may be omitted in small infant or those who are having normal inspection findings.
However, if there is definite restriction of movement of one hemi-thorax, palpation should be done.
Palpation should include location of the trachea in older children or when there is
asymmetry of chest or if there is restriction of movement of one hemi-thorax.
Proceed to auscultation.
Auscultate in 6 main area; above both clavicle, below both clavicle in the mid-clavicles line,
in the 4th inter-costal space in the mid-axillary line, over the apex and base of both axilla,
between the scapula and in the lower part of the chest posteriorly.
The back may be left after the end of the examination.
Describe the breathing sounds as normal or abnormal.
Although there is confusion in the literature, the American Thoracic Society [ATC]
recommends classifying abnormal breath sounds as either interrupted [such as fine or
coarse crackles] or continuous [such as wheezing or rhonchi].
If there is wheezing, mention weather it is mono-phasic or bi-phasic [expiratory or both
inspiratory and expiratory] and try to have a rough estimate of the magnitude of the
prolongation of the expiratory phase by mentioning the inspiratory to the expiratory phase
ratio [by saying, for instance, 1:4 or 1:6 ]. This is not easy and comes with experience.
If there is any suggestion of CHF, the heart sounds, any added sounds, murmur and the
presence of gallop rhythm should be looked for.
In addition, basal fine crepetation and liver enlargement, after the end, should be sought.
If there is bronchial breathing, describe it, its location and the other associated sounds.
Percussion must be done to look for hyper-resonance or dullness [especially, the
characteristic stony dullness of pleural effusion]. This may be omitted in neonates and small
infants unless there is asymmetrical movement of the chest of there are signs of hyperinflation.
Percussion need to be performed in the following situations; 1]- restricted movement of one
hemi-thorax, 2]- asymmetrical chest, 3]- bronchial breathing, 4]- and when pleural effusion
is suspected.
The mental status and the level of consciousness [LOC] should be assessed, as decreased
LOC can be caused by both hypoxemia and hypercarbia.
-
-
-
-
After performing the physical examination, summarize your findings in one paragraph
pointing to the positive findings and the most important negative findings.
Then, characterize the respiratory derangement as one of the following 3 categories ; 1]primary respiratory derangement, 2]- secondary to other some disease process, 3]- or part
of a more generalized condition [such as in systemic lupus eryethromatosus [SLE]; where
you may find, for instance, the characteristic malar flush and obvious joint swelling and/or
purpura].
Always, examine the liver because liver dysfunction can cause hypoalbunemia leading to
pleural effusion and pulmonary edema and causing respiratory distress [RD] or it can be
enlarged due to CHF causing RD from congested lungs or may be a manifestations of right
heart failure and cor pulmonale from chronic lung disease [CLD] such as bronchectaisis.
One of the most important diagnostic tool for respiratory illnesses is the plain chest X-ray
[both the frontal and the lateral films].
The frontal film is usually anterior-posterior [AP] film in infants and sick children, however,
in ambulatory stable older child, the posterior-anterior [PA] film is the preferred.
The lateral film is the preferred to assess for hyper-inflation, as it shows flattening of the
diaphragm and increased space behind the sternum.
The lateral docubetus films may be used to evaluate for pleural effusion.
Doing both the expiratory and the inspiratory films is needed if there is any suspension of
foreign body aspiration.
The foreign body will a act as a ball-valve mechanism  air is entering, but not getting out of
the lungs. So, the expiratory film will show hyperinflated lungs where the foreign body is
located and mediastinal shift toward the opposite side.
More than that, the foreign body can be seen if it is radio-opaque.
FINGER CLUBBING
-
-
Finger or toe clubbing is an important physical signs.
For documentation of finger clubbing, 4 criteria should be present.
These 4 criteria are; 1]- increased sponginess of the nail bed, 2]- loss of the acute angle
between the nail and the nail bed, 3]- increased curvature of the nail [convexity outward],
4]- and increased bulkiness of the soft tissues over the terminal phalanges.
Majority of individual who have finger and/or toes clubbing have respiratory illnesses.
However, idiopathic and familial variant can occur in normal individuals.
In normal finger or toe, the angle between the nail and the nail bed is, approximately, 160
degrees.
In early clubbing, the angle between the nail and the nail bed is, approximately, 180 degree
and is caused by tissues proliferation on the terminal phalanx.
In late clubbing, the angle between the nail and the nail bed is more than 180 degree and the nail bed is
visibly swollen.
CAUSES OF CLUBBING
-
The most important causes of clubbing are shown on the next table;
SYSTEM
DISEASE
Respiratory system
Empyema
Bronchectaisis
Lung abscess
Benign intra-thoracic tumor
Bronchogenic carcinoma
Cardiovascular system
Liver
Gastro-intestinal tract
[GIT]
REMARKS
Particularly, squamous cell
carcinoma
Mesotheliioma
Pulmonary arterio-venous fistula
Fibrosing alveolitis
Asbestosis
Advanced pulmonary fibrosis of
any cause
Cyanotic Congenital Heart
Diseases [CHDs]
Infective endocarditis
Atrial myxoma
Cirrhosis
Ulcerative Colitis
Crohn Disease
Familial
BREATHING SOUND
-
The normal and abnormal breathing sounds are shown on the table below
THE SOUND
RELATION OF
DIAGRAM
NORMAL
ABNORM
INSPIRATION TO
OF THE
LOCATIO
AL
EXPIRATION
SOUND
N
LOCATIO
N
VESICULAR
Inspiration > expiration
BRONCHOVESICULA
R
Inspiration = expiration
BRONCHEAL
Inspiration < expiration
Throughout
the lung
field
First or
second ICS
at the level
of the
bifurcation
of the
trachea
None
Over the
trachea
Lung area
Peripheral
lung field
ADVENTITIOUS REATHING SOUND
-
The adventitious breathing sounds are summarized on the next table;
THE SOUND
THE CHARACTERISTICS
THE CAUSE
CRACKELS [Fine]
Intermittent, high pitched, soft
popping sound. It is heard late in
inspiration. It indicates the presence
of fluid inside the alveoli
CRACKLES [Medium]
Intermittent, wet, loud, non
crackling, medium pitched sound. It
is heard early or mid inspiration. It
clears with coughing. It indicates
fluid in bronchioles and bronchi
Loud, bubbling, low pitched sound. It
is heard expiration and clears with
coughing. It indicates fluid in
bronchioles and bronchi.
Continuous, snoring, low pitched
sound. It is heard throughout the
respiratory cycle [both the
inspiratory and the expiratory
phase]. It clears with coughing. It is
indicative of involvement of large
bronchi and trachea. It can be a
NORMAL sound.
Continuous, musical and high pitched
sound. It is heard in mid to late
expiration. It indicates the presence
of edema and obstruction in the
small airways. It may be audible
without a stethoscope. It is caused by
partial obstruction of the bronchi and
bronchioles leading to narrowing.
This may be caused by lesion within
their lumen, in their walls or
compression from outside in few
cases. Wheezes when present is
UNMISTAKABLE.
Sonorous, musical sound. It is heard
on inspiration.
Whistling, sighing sound. It is heard
on expiration.
Grating, rubbing, loud, high pitched
sound. It is due the movement of one
layer of the pleura over the other in a
jerking motion, generating a creaking
sound, similar to that produced by
bending a stiff leather. It is heard
1]- Congestive heart failure
[CHF].
3]- Pneumonia.
4]- Pulmonary
Tuberculosis.
Pulmonary edema.
CRACKELS [Coarse]
RHONCHUS
WHEEZE
INSPIRATORY
AUDIBLE WHEEZE
EXPIRATORY
AUDIBLE WHEEZE
PLEURAL FRICTION
RUB
1]- Bronchitis.
2]- Resolving pneumonia..
Bronchitis.
Broncheal asthma [BA].
High airways obstruction.
Low airways obstruction.
Inflamed pleural surfaces.
STRIDOR
SNORING
during both inspiration and
expiration. It is ALWYS pathological.
Harsh, audible, crowing, high
pitched sound. It is heard during
inspiration. It indicates UAWO
[incomplete]. It is usually associated
with hoarseness, brassy cough,
dyspnea, sterna retraction during
inspiration and listlessness. The
patient usually uses the accessory
muscles of respiration. It is
frequently seen in infant sand is
often attributed to the following
factors; 1]- small sized larynx, 2]loose submucous connective tissues
around the glottis region, 3]- and
rigid cricoids cartilage [encircling the
sub-glottic zoon].
1]- Croup.
2]- Spasmodic croup.
3]- Congenital stridor
[congenital
laryngiomalacia].
4]-Hypocalcemia.
5]- Neurogenic stridor
[bilateral vocal cord
paralysis].
6]- Other congenital
anomalies [congenital
laryngeal stenosis, web,
cyst or neoplasm].
7]- Extrenisc compression
of the larynx and the rest
of the UAW [vascular ring,
vascular sling, mediastinal
goitor, tumors of the neck,
lymphangioma,
thyroglossal cyst,
micrognathia,
macroglossia,
diaphragmatic hernia].
8]- Down syndrpme with
hydrocephalus.
9]- Foreign body aspiration
or ingestion.
10]- Epiglottitis.
Gastro-esophageal reflux
disease [GERD].
Audible, coarse rales produced by air
bubbling through the fluid secretions
of the trachea-broncheal tree.
RUTTLING
The crackles is also called rales or crepitation.
The crackles [rales or crepitation] are short explosive sounds, thought to represent the equalization
of the intra-luminal pressure as the collapsed small airways open during the inspiratory phase of the
breathing [respiratory] cycle.
So, it occurs in disease processes causing smaller airways closure, whether due to airway damage
[such as in chronic bronchitis] or increased interstitial volume [such as in pulmonary edema and fibrosing
alveolitis (FA)].
With diffuse diseases, the effect of the gravity makes the crackles more prominent in the basal
dependent areas of the lungs.
When approaching stridor, the differential diagnoses depends on whether the stridor is acute or
chronic [persistent] and recurrent.
Diphtheria, retropharyngeal abscess, angio-neurotic edema, anaphylaxis and measles should not be
forgotten as possible causes of stridor.
-
THE PHYSICAL SIGNS OF RESPIRATORY DISEASES
-
The normal and abnormal breathing sounds are shown on the table below
THE DISEASE
MEDIASTI CHEST
PERCUS
TACTILE
BREATH
ADDED
NAL SHIFT WALL
ION
FREITUS;
SOUNDS
SOUNDS
NOTES
VOCAL
MOVEME
NT
RESONAN
CE
COLLAPSE
PLEURAL
EFFUSION
CONSOLIDATION
PNEUMOTHORAX
PLEURAL
THICKINING
Yes
[toward
affected
hemithorax]
Yes [away
from the
affected
hemithorax]
No
Yes [away
from the
affected
hemithorax]
No
Reduced
Reduced
Reduced
Reduced
Reduced
Reduced
Reduced
Reduced
Normal Reduced
to
reduced
Reduced Increase
d
Increased
Reduced
Increased
[bronche
al sound]
Reduced
Reduced
Reduced
Reduced
Reduced
No
Occasionall
y [rub]
Crackles
Occasionally
[click]
No
THE NORMAL RESPIRATORY RATE [RR] RANGES BY THE AGE
THE AGE
THE RR RANGE IN breaths per minute
(bpm)
Birth – 6 months of age
6 months – 1 year of age
1 – 3 years of age
3 – 5 years of age
5 – 12 years of age
> 12 years of age
30 – 60
30 – 50
24 – 40
22 – 34
14 – 25
12 – 20
PULMONARY FUNCTION TESTS [PFTs]
The pulmonary function tests [PFTs] provide objective and reproducible measurements of the airway
functions and the lung volumes.
The PFTs are used for the following purposes; 1]- to characterize the pulmonary disease processes,
2]- to assess their severity, 3]- and to follow the patient response to therapy.
Generally speaking, the PFTs are groups of tests are based on the various functions of the lungs
[such as; the ventilation, the diffusion and the perfusion].
PFTs provide the pediatrician with invaluable information to assess the degree and characterize the
pulmonary pathology, however, they do not provide pathological diagnoses, but instead, confirm the
clinical suspicion of a restrictive or an obstructive pathology.
PFTs are often performed to follow the progress of the disease process and the patient response to
therapy.
PFTs include the following; 1]- the tests which are based on the assessment of the ventilatory
function, 2]- the tests which are based on the assessment of the diffusion capacity of the lungs, 3]- the
tests which are based on the assessment of the lung perfusion, 4]- and the other tests.
The tests which are based on the assessment of the ventilatory function are either; spirometric or
non spirometric.
The spirometric tests include the static and the daynamic spirometry.
The static spirometry measures all of the lung volumes and lung capacities in liters [L], while the
dyanamic spirometry measures the values which are rated to the time [measured in liter per second
(L/s)] such as; the forced expiratory volume in one second [FEV1].
The peak expiratory flow rate [PEFR] is a non spirometric test.
The spirometry include the following; a)- the lung or the pulmonary volumes, b)- the lung
[pulmonary] capacities, c)- the forced vital capacity [FVC], d)- and the forced expiratory volume in one
second [FEV1].
The PEFR is the maximum flow rate generated by the patient during a forced expiratory maneuver.
PEFR is an effort dependent and insensitive to the small airways functions.
PEFR is useful in following the asthmatic patients and their response to therapy.
PEFR is used to compare the trends in the patient own values or to compare the patient own values
with predicted values.
The most sensitive, reproducible and the best PFT is to compare the patient current values to his
previous values.
The dynamic spirometry is, simply, a plot of the air flow rated versus the time.
The forced vital capacity [FVC] is a measurement obtained during a forceful, rapid and complete
expiration from the total lung capacity [TLC] to the residual volume [RV].
FVC is often done before and after a dose of a bronchodilator to assess the patient response, and/or
after a bronchial challenge to assess the degree of the airways hyperactivity.
FVC can be performed reliably by most of the children who are > 8 years of age.
The FVC is the maximum volume of air exhaled from a maximum inspiration.
Beside the usefulness of the FVC in measuring the vital capacity by a hand-held spirometer, it can be
useful, also, in predicting hypoventilation.
A FVC of < 15 ml/kg may be an indication for the need of mechanical ventilation.
The FEV1 is the volume of air exhaled [expired] during the first one second of the forced vital
capacity maneuver.
The FEV1 is normally > 80 % of the FVC.
This means that FEV1/FVC = 0.8.
Value < 75 % [0.75] points to an obstructive pulmonary disease process [such as bronchial asthma
[BA], chronic obstructive pulmonary disease [COPDD] (chronic bronchitis and emphysema)].
In restrictive lung diseases, the ratio of FEV1 to the FVC [FEV1/FVC] is maintained within the normal
because both the FEV1 and the FVC are decreased.
However, in obstructive pulmonary diseases, the FEV1 is reduced to larger extent than the FVC.
Also, if the FEV1 is normal, while the FVC reduced, this points out to a restrictive pulmonary disease
process.
The FEV1 is the best single measure of the airways function.
The tests which assess the diffusion capacity [TLCO] of the lungs include the arterial blood gases
[ABGs] analysis.
The ventilation/perfusion [V/Q] scan is used to assess the lungs perfusion and helpful to diagnose
pulmonary embolism and sequestration of the lungs in infants.
The other tests include the following; 1]- the other radiological tests [such the computerized
tomography [CT] of the chest, the magntic resonance imaging [MRI] of the chest and the ultra-sound
[US] for evaluation of possible pleural effusion], 2]- the culture of the sputum [or in children, the culture
of the early morning gastric aspirate], 4]- the gram stain and analysis of the sputum, 5]- the sputum
testing for evidence of lipid laden macrophages [aspiration] or lipid laden hemosidren [hemosidreniosis],
6]- the pleural fluid [PE] fluid analysis, gram stain, microscopy, chemistry, zelhi nelsen stain for
tuberculosis and culture for both bacteria and fungi], 7]- the pleural biopsy, 8]- the bronchoscopy, 9]- and
the open lung biopsy.
PLEURAL FLUID EXAMINATION
-
The PE may be an exudates or transudate, serous, sero-sangiounus or bloody [hemothorax]
Exudate indicates an inflammatory process [usually bacterial pneumonia complicated by PE].
The main differences between exudate and transudate are shown on the next table;
THE DIFFERENCES BETWEEN EXUDATE AND TRASUDATE
PARAMETERS
LEUKOCYTES count per
mm3
Polymorphs in percent
TRANSUDATE
< 1000
EXUDATE
> 1000
> 50 % in acute
bacterial infection
Lymphocytes
PROTEIN IN g/dl
Glucose
LACTATE
DEHYDROGENASE
[LDH] LEVEL IN U/L
PLEURAL TO SERUM
PROTEIN RATIO
PLEURAL TO SERUM
LDH RATIO
pH
AMYLASE LEVEL
>50 % [may be >50
% monocytes]
<3
equal to the serum glucose
level
< 300
> 50 % in tuberculosis and
malignancy
>3
< 75 % of the serum
glucose level
> 300
< 0.5
> 0.5
< 0.6
> 0.6
> 7.3
Equal to 7.3
Increased in case of
pancreatitis
By Dr: Attallah Al Mutairy
Consultant Pediatric Intensivist
Head of PICU
Yamamamh Maternity & Children Hospital [YMCH