Fetal transitional

Question 1

what seals flaps of foramen ovale over time?

Answer 1

fibrocytes

Question 1

pgE1 is destroyed…

Answer 1

in lungs

Question 2

patent foramen ovale

Answer 2

shunts higher oxygenated blood from the right atrium to the left atrium

Question 2

% that flows through lungs? % through ductus arteriosus?

Answer 2

only 8 % through lungs, 60% through ductus arteriosus

Question 2

what could happen is change in resistance isn’t gradual?

Answer 2

abrupt change in pulmonary resistance could lead to right ventricle stretch –> fatal arrhythmia

Question 3

in fetus, pulmonary vasculature resistance is ______? why?

Answer 3

high because lungs aren’t filled with air and pulmonary arterioles are contracted

Question 3

what three situations would make a patent ductus arteriosus helpful?

Answer 3

congenital heart disease heart defects hypoplastic left heart syndrome

Question 4

PPHN

Answer 4

persistent pulmonary hypertension of the newborn

Question 5

right side of heart receives…

Answer 5

mix of high and low oxygen blood that flows into pulmonary artery

Question 5

what connects the pulmonary artery to the aorta in fetus?

Answer 5

ductus arteriosus

Question 6

ductus arteriosus becomes…

Answer 6

ligamentum arteriosum

Question 7

placenta supplies…

Answer 7

oxygen to fetus

Question 7

fetal o2 delivery =

Answer 7

combined ventricle output - umbilical/placental flow

Question 8

at birth, relative resistances?

Answer 8

after umbilical cord is clamped, systemic resistance becomes high lungs inflate and pulmonary arterioles relax –> lower resistance

Question 9

what finally encourages relaxation of pulmonary arterioles?

Answer 9

higher oxygen saturation after first breath air filled lung has lower resistance to blood flow and pO2 stimulates NO production (a potent pulmonary vasodilator)

Question 11

fetal circulation from placenta all the way back path….

Answer 11

placenta umbilical vein –2/3 to hepatic veins –>portal veins and liver –1/3 to ductus venosus –>IVC –> R atrium From r atrium, 2 paths –a little bit goes to r ventricle –> pulmonary artery –> ductus arteriosus –most goes through foramen ovale –> L atrium –> l ventricle –> aorta –> body aorta –> internal iliac a –> umbilical a –> placenta

Question 12

how to treat hypoplastic left heart?

Answer 12

if ductus arteriosus clses there will be no systemic flow –> so use pgE1 infusion until surgery then either norwood procedure or fontan procedure

Question 13

what keeps the ductus arteriosus open in utero?

Answer 13

placental production of PG E (fetal production occurs too but unknown where)

Question 13

which connects IVC and SVC into one inflow to heart: norwood or fontan procedure?

Answer 13

fontan

Question 14

pphn treatment

Answer 14

1)oxygen - helps saturate lungs and acts as a pulmonary vasodilator 2) NO - vasodilator 3) vasopressors - pushes blood toward lungs and increases systemic pressure

Question 16

after first breath, what happens…

Answer 16

breath decrease in pulmonary resistance increase in L atrium pressure relative to the right closes foramen ovale 2) increase in blood O2 decrease in PGs (destroyed in lungs and by oxygen) closes ductus arteriosus

Question 18

in fetus which carries more fetal cardiac output, ascending aorta or ductus arteriosus?

Answer 18

ductus arteriosus! (60%)

Question 19

decreased pulmonary resistance after lungs fill with air leads to preferential…..

Answer 19

flow to lungs through pulmonary a

Question 20

name the three fetal shunts

Answer 20

ductus venosus ductus arteriosus patent foramen ovale

Question 21

in pphn, minimal blood flow to lungs leads to…

Answer 21

hypoxia and acidosis

Question 22

two phases of ductus arteriosus closure

Answer 22

constriction - placental source of pgE is removed and increased flow to lungs breaks down the rest; higher oxygen also increases closure (first few days) then remodeling - fibrocytes infiltrate and endothelium hypertrophy in 2-3 weeks it will becomes –> ligamentum arteriosum

Question 23

ductus venosus

Answer 23

shunts oxygenated blood from the unbilical veins away from liver to the inferior vena cava

Question 23

from the left ventricle the highest oxygen blood goes…

Answer 23

through ascending aorta to brain!

Question 26

in utero, relative resistances?

Answer 26

lungs are high resistance systemic circuit is low resistance placenta is very low resistance(blood preferentially flows to it through umbilical a)

Question 27

what causes production of NO?

Answer 27

increased pO2 after fetus breathes

Question 29

aortic pressure = ______ pressure

Answer 29

pulmonary artery (in fetus)

Question 30

fetus exists in an _____ environment

Answer 30

hypoxic

Question 31

at birth what are the three anatomical changes and three physiological changes?

Answer 31

three shunts close (DV, PDA, PFO) pgE1 decreases, pO2 increases, PVR decreases

Question 33

fetal hb vs adult hb

Answer 33

fetal hemoglobin has higher affinity for oxygen –> a higher percent of hb can bind to oxygen at lower partial pressures (hypoxic env)

Question 35

why does it matter that the ductus arteriosus and foramen ovale close?

Answer 35

prevents blood from bypassing pulmonary circuit

Question 36

clamping the umbilical cord –>

Answer 36

stops ductus venosus flow and lowers r atrium pressure helping to close foramen ovale

Question 37

at 4-6 weeks how should L and R ventricle pressure compare?

Answer 37

right should be 1/4 of what left is

Question 38

foramen ovale closure

Answer 38

more blood to lungs more blood to L atrium increases L atrium pressure closes foramen ovale over time, fibrocytes seal flaps

Question 39

change of pulmonary resistances is ______

Answer 39

biphasic -initial drop -4-6 weeks of gradual lowering to adult level