Developmental chest Flashcards
Where does oxygenation of blood occur in fetuses?
placenta
What are the patencies?
ductus arteriosus
foramen ovale
Right to left shunt through atria; Well O2 blood to the ascending aorta to UE’s and brain
Foramen ovale
Shunt from pulmonary artery to aortic arch (descending aorta);Less well O2 blood to the LE’s
ductus areteriosus
Occurs with the initiation of breathing following separation of the placenta and ventilation of the lungs; Systemic resistance increases (Increased BP in extremities); Pulmonary resistance decreases (Inflation of the lungs, blood flows to them); Process results in closure of Foramen Ovale and Ductus Arteriosus; Right and left side now work in series not parallel
transitional circulation
What makes the pulmonary system vulnerable in newborns?
- Airways are narrower (more easily obstructed)
- High larynx - Allows to breathe and swallow simultaneously
- Obligatory nose breathers
- Low compliance of lung tissue
- Surface area for gas exchange is reduced
- Thick alveolar walls (diffusion is decreased)
- Diaphragm has fewer type I fibers (Easy fatiguability leading to incr work of breathing)
What is the shape of the chest in the anterior plane?
triangular
What is the shape of the chest from a lateral view
lower chest is circularly shaped
- rips horizontal with narrow intercostal spacing
- diaphragm is horizontal at insertion with ribs
What is the RR of newborns?
40-60 bpm
What is the muscular influence on newborn breathing?
- flexion in utero = tight ant chest wall
- intercostal mm have not developed an appropriate length-tension relationship = unable to expand chest in all 3 planes
How does the chest wall open in infants?
prone on elbows
- ant chest is no longer flat
What does the chest wall look like in an anterior and lateral view in 3-6 month olds?
Frontal = rectangular lateral = lower chest circular (instead of flat); still horizontal ribs - primarily diaphragmatic breathers - RR still 40-60 bp - trunk proportion still 1:3
What does the chest wall look like in an anterior and lateral view in 6-12 month olds?
frontal = rectangular
lateral = elliptical shape
- antigravity movements in all trunk planes
- RR 30 bpm by 12 months
What does the rib cage look like a t 6-12 months?
- Elongated
- Downward rotation of ribs - Abdominals, Gravity
- Separation of ribs - Increased length tension of intercostals; ncreased length tension of diaphragm – becomes more elongated/less circular
- Trunk (Chest and Abdomen); Functioning as one unit, Proportion 1:1
What does the chest wall look like in 4-5 y/o’s?
- Rib cage [will take up] > ½ of trunk
- Interrelationship between abdominals and intercostals - Can now use these together; Paradoxical at this age
- Quick deep inhalation w/o chest wall collapsing due to increased negative inspiratory forces; Begins to use breath holds as postural support
