4. ANATOMICAL DIFFERENCES
1.RIB CAGE & CHEST SHAPE
INFANT ADULT
•Ribs are soft &
cartilagenous & the angle of
rib with sternum is horizontal
•Inter-costal muscles are
poorly developed with
inefficient Ventilation ,
requirements are met by
increasing respiratory
rate
•The cross-sectional shape of
thorax is elliptical.
•Ribs are more calcified &
rigid & angle of rib with
sternum is oblique hence
bucket handle movement is
possible.
•Inter-costal muscles are well
developed & ventilation
requirements are met by
increasing respiratory depth.
5.
6. • angle is oblique & relative high
muscle mass & high content of
high endurance fibres & less
vulnerable to fatigue.
•adults respond to stress with
downward movement of
diaphragm.
2.DIAPHRAGM
•The angle of insertion of
diaphragm is horizontal &
there is low relative muscle
mass& low content of high
endurance muscle fibres &
hence more vulnerable to
fatigue.
•infants respond to hypoxia
with inward movement of
intercostals( thoracic
retractions.)
7.
8. ● •Position of Larynx & hyoid
cartilage is higher( more
anatomical protection as valve
in infants )
•In adults position of Larynx &
hyoid bone is relatively lower (
position desecends with age )
•Bronchial walls are more rigid
with less mucus gland.
● Bronchial walls are more
cartilagenous with more
mucus gland & hence infants
are more susceptible to
mucus obstruction.
9.
10. 4.AIRWAY DIAMETER
•In infants airway diameter is only
1/3rd as compared to adults &
hence more respiratory resistance
& breathing rate.
Narrowest part of airway is cricoid
rings in infants .
● The airway diameter in
adults is relatively larger
● Narrowest part of airway in
adults is vocal cord/Larynx.
11.
12. In infants cilia is poorly developed
& hence more chances of retention
of secretions.
•Alveoli are not fully developed
which reduces the surface area for
gaseous exchange & also there is
deficiency of surfactants which is
the major cause of Neonatal
Respiratory Distress Syndrome.
5.Cilia, Alveoli & Surfactants
•In adults cilia is fairly devloped
with efficient muco-ciliary
escillation mechanism.
•Alveoli are well developed with
sufficient amount of
surfactants,which prevents
alveolar collapse.
13.
14. 6.Collateral Ventilation & Lymphatic
tissue
•At birth there is no devloped
pathway for collateral -
Ventilation upto 6 years of age
& hence more chances of
alveolar collapse.
•Lymphatic tissue in infants are
enlarged which is responsible for
upper airway obstruction.
•Heart & other organs are
relatively larger which leaves
less space for chest expansion.
•Collateral pathways are well
developed.
•less chances of airway
obstruction in adults
•enough space in thorax for
chest expansion in adults.
15. PHYSIOLOGICAL DIFFERENCES
1.RESPIRATORY COMPLIANCE
● Respiratory Compliance in
adults is relatively higher
because of calcified chest
wall & well equipped
intercostal muscles which in
turn are able to exert
enough pressure that is
required to increase the
volume in the lungs.
● Respiratory Compliance is
the measure of pressure
required to increase the
volume of air in the lungs &
that is directly proportional
to child size.
● Respiratory Compliance is
less in infants because of
soft cartilagenous chest wall
& less equipped intercostal
muscles.
16. 2.Ventilation & Perfusion & Breathing
pattern
• In infants ventilation is
mostly distributed to the
uppermost lungs &
perfusion to the
dependent regions.
•Breathing pattern is
irregular & episodes of
apnea is common in
infants.
•In adults both Ventilation &
perfusion is distributed to the
dependent regions & also wt. of
abdominal content provide
weightage to the dependent
diaphragm.
•Breathing pattern is regular &
episodes of apnea is less common
in adults.
17.
18. ● Infants have relatively more
metabolic rate & hence
oxygen consumption is more.
● Infants respond to hypoxia
with bradycardia &
pulmonary vasoconstricton.
● Respiratory muscles tire
more quickly ( only 30%slow
twitch/type 1 muscle fibres.)
● Adults have relatively less
metabolic rate.
● Adults respond to hypoxia
with tachycardia &
pulmonary vasodilataion.
● Respiratory muscles consist
of approx.50% type 1 high
endurance muscle fibres.
OXYGEN CONSUMPTION &
RESPONSE TO HYPOXIA & MUSCLE
FATIGUE
