Fetal Respiratory Transition Flashcards
what weeks of development is pseudoglandular respiratory development?
5-15 weeks
what weeks of development is canalicular respiratory development?
16-24 weeks
what weeks of development is saccular respiratory development?
24-36 weeks
what weeks of development is alveolar respiratory development?
36-38 weeks
in what two stages of respiratory development are most preterm babies born in?
canalicular or saccular
cortisol spikes in weeks 30-36 weeks gestation, what two benefits does this have on respiratory development?
enhances lung fluid clearance
increases surfactant production
what can you give preterm babies to help with surfactant production?
antenatal glucocorticoid therapy
what is the O2 sat in fetal pulmonary circulation?
55%
which ventricle of the heart is in charge of 2/3 of fetal output and which is 1/3?
right ventricle is in charge of 2/3 and left 1/3
what is the purpose of the fluid made by the lung in gestation?
to help expand the lung
what cells make and secrete fluid in fetal lung?
the epithelial cells
in the fetal circulation, what is providing the preload of the heart?
the umbilical vein
after cutting the umbilical cord, now the preload of the heart is managed by what?
pulmonary venous return
what molecule leads to the decrease in pulmonary vasculature resistance following birth?
NO
what must happen to the fetal lung fluid following birth? what two things help this?
fetal fluid must be reabsorbed by epithelial cells…helped by uterine contractions and pressure gradients and the hormones
what are the two mechanisms of fluid clearance from lungs?
exit via trachea
exit through epithelial cells and into interstitium like edema then out the lymphatic drainage
how long does it take for the lung fluid to get cleared after birth?
4-6 hours
why are babies blue right after birth? how long does it take for this to change?
babies are blue because the ductus arteriosus is still open and it takes about 10 minutes for this to close
do we usually cut the cord right away now?
no…cutting the cord right away was done but was associated with negative effects
what are the three negative effects of cutting cord immediately?
pulmonary vascular resistance is still high and pulmonary venous return is low and so preload is low
systemic vascular resistance will shoot up too
what is respiratory distress syndrome?
inability to recruit alveoli due to low levels of surfactant
give three reasons why pulmonary hypertension may remain in a new born?
respiratory distress syndrome
aspiration of meconium/pneumonia
pulmonary hypoplasia
when pulmonary hypertension remains in a newborn, what ensues?
shunts stay open and are still R to L, baby remains in a hypoxic state
what is TTN? what usually causes it?
transient tachypnea of the newborn
usually caused by slow fluid resorption in the lung
