the first breath Flashcards
1
Q
stages of lung development
A
Embryonic 0-5 weeks
Pseudoglandular 5-17 weeks
Cannalicular 16-25 weeks
Alveolar 25 weeks-term
2
Q
systemic blood vessels
A
- purpose: deliver oxygen to hypoxic tissues
- hypoxia/acidosis/CO2 is a vasodilator
- oxygen is a vasoconstrictor
3
Q
pulmonary blood vessels
A
- purpose: pick up oxygen from lung
* oxygen is a vasodilator #hypoxia/acidosis is a vasoconstrictor
4
Q
fetal lung
A
Lung is not useful organ to fetus PaO2 = 3,2 kPa (31000 feet) Shunting of blood right to left • High pulm Vasc resistance (hypoxia) • Tissue resistance (fluid filled) • Low systemic resistance (placenta)
5
Q
lung fluid
A
» Fetal airways are distended with fluid
» Fluid aids in lung development
» Actively secreted by lungs
6
Q
the first breath
A
- Fluid squeezed out of lungs by birth process
- Adrenaline stress increased surfactant release.
- Air inhaled
- Oxygen vasodilates pulmonary arteries
- Umbilical arteries constrict
- Ductus arteriosus constricts
7
Q
surface tension
A
measure of the force acting to pull a liquid’s surface molecules together at an air-liquid interface
8
Q
surfactant
A
- Virtual abolition of surface tension
- Allows homogeneous aeration
- Allows maintenance of functional residual capacity
9
Q
surfactant production
A
- Accelerated by
- Distension of alveoli
- Steroids
- Adrenaline
10
Q
surfactant management
A
- Warmth
- Surfactant replacement (if intubated)
- Oxygen and fluids
- Continuous Positive Airway Pressure (maintain lung volumes, reduce work of breathing)
- Positive pressure ventilation if needed
