Fetal lung and Heart development Flashcards
At what week are lungs fully developed
36 weeks
At what stage and how many weeks do the development of the trachea and major bronchi occur
Embryonal stage day 26- 52
When does surfactant development begin
24-25 weeks
What is the L/S ratio
predictive index of lung & bone maturity before birth and the risks of development of resp distress
How is the LS ratio test done?
By taking amniotic fluid
If ratio is below 1.5 what does it mean for the baby?
Baby is at high risk for developing RD
What does the fetal lung do?
Moves fluid
How does gas exchange occur for NeoNates?
Mother provides gas exchange
What does the umbilical arteries do?
return deoxygenated blood from the fetus to the
placenta
What does umbilical vein do?
returns oxygenated blood from placenta to fetus
What are the three fetal shunts
Ductus Venosus
Ductus Arteriosus
Foramen ovale
What does the placenta do
transfers maternal oxygen and nutrients to the fetus
What is special about fetal circulation
It is opposite of normal circulation
What is a low amiotic fluid balance called
Oglo
If the baby is born at 26 weeks how does it affect alveoli
They will not be fully developed
If the LS ratio is = to or greater than 2 what does it mean
baby at low risk for RD
If LS ratio is below 2 what does it mean
Baby is at risk for RD
If LS ratio is below 1.5 what does it mean
Baby at high risk or RD
How is the fetal lung different than neonate lung
In utero lungs serve no resp purpose
describe the Ductus venosus
Fetal vascular channel in the fetus passing through liver and joining Umbilical vein with ICV
Ductus Arteriosus
Fetal vascular channel joining pulmonary artery directly to the descending aorta
Foramen ovale
opening in septum between right and left atria in the fetal heart
what is a CHD
any anatomic abnormality present in heart at birth
What CHDs are ductual dependent
coarctation of aorta
interrupted aortic arch
aortic valve stenosis
Hypoplastic left heart syndrome
Pulmonary atresia
What is ductal dependency
Ductus Arteriosus needs to stay open if not baby will die
what happens when an CHD has a right to left shunt
blood will bypass lungs leading to no pulmonary bloodflow
enters the systemic circulation , lack of O2 gas exchange
What happens when an CHD has a left to right shunt?
oxygenated blood is shunted left to right and mixes with deoxygenated blood, baby will not have proper oxygenation and circulation.
Is a left to right shunt cyanotic or non-cyanotic
non cyanotic
What is Patent Ductus Arteriosus
Ductus Arteriosus fails to close after birth
What results from Patent Ductus Arteriosus
excess bloodflow of pulmonary circulation
Hypoperfusion of systemic circulation
How is Patent Ductus Arteriosus treated
Oxygen therapy
Surgery
Indomethacin ( helps close pda, protects baby’s brain)
How is PDA tested for?
Pulse ox screening
What do results of pulse ox screening show
O2 sat on right wrist arm much higher than O2 sat for Foot
what is Atrial Septal Defect (ASD)
A CHD where there is a hole/opening in the wall that separates the atria
What Type of shunt is ASD
Left to right (non cyanotic)
What effect does ASD have on heart
atrium blood flows backwards, Right ventricle becomes hypertrophic
what are characteristics of cyanotic shunts
right to left
Blood from right side of heart not oxygenated
Bypasses lungs
What are characteristics of Acyanotic shunts
Left to right shunt
Blood from left side of heart (oxygenated)
Transfers back to right side of heart
What does CHD involve anatomically
Int walls of heart
Valves inside the heart
Arteries and Veins that carry blood to heart/body
what causes MAS
Fetal hypoxia
Stress
How does stress cause the baby to aspirate ?
Fetus gasps due to vagul response when stressed and causing fluid to move past it.
What are complications for MAS
o Disrupted surfactant production
o Pulm hypertension
Right to left shunt
Chemical pneumonitis
Potential airway obstruction
what is the most common CHD
Ventricular septal defect
What does Nitric do?
relaxes smooth muscle of pulmonary vascular system and reduces PVR
When is Nitric indicated
when OI index is greater than or equal to 25
Why does lung development suffer with a congenital diaphragmatic hernia
Due to lungs being compressed in utero, leading to underdeveloped lungs and shifted heart.
What is one of the big differences between croup and epiglottis
Croup is a viral infection epiglottis is a bacterial
What is the main indicator of croup on a cxr?
steeple sign on neck
What are complications of croup
Subglottic swelling
mucus glands increase production
Cillia lose effectiveness
Narrowing of the airway
Main causes of Epiglottis
Haemophilus influenzae type B
Trauma from repeated intubation attempts
What are risk factors for epiglottis
Children 2-6 years of age
males
What is main CXR presentation for epiglottis
thumb sign
What is presentation of epiglottis
High Fever
Sore throat
Stridor
Cherry red epiglottis
