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Flashcards in Fetal transitional Deck (39)
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1

what seals flaps of foramen ovale over time?

fibrocytes

1

pgE1 is destroyed...

in lungs

2

patent foramen ovale

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

2

% that flows through lungs? % through ductus arteriosus?

only 8 % through lungs, 60% through ductus arteriosus

2

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

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

3

in fetus, pulmonary vasculature resistance is ______? why?

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

3

what three situations would make a patent ductus arteriosus helpful?

congenital heart disease heart defects hypoplastic left heart syndrome

4

PPHN

persistent pulmonary hypertension of the newborn

5

right side of heart receives...

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

5

what connects the pulmonary artery to the aorta in fetus?

ductus arteriosus

6

ductus arteriosus becomes...

ligamentum arteriosum

7

placenta supplies...

oxygen to fetus

7

fetal o2 delivery =

combined ventricle output - umbilical/placental flow

8

at birth, relative resistances?

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

9

what finally encourages relaxation of pulmonary arterioles?

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

11

fetal circulation from placenta all the way back path....

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

12

how to treat hypoplastic left heart?

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

13

what keeps the ductus arteriosus open in utero?

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

13

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

fontan

14

pphn treatment

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

16

after first breath, what happens...

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

18

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

ductus arteriosus! (60%)

19

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

flow to lungs through pulmonary a

20

name the three fetal shunts

ductus venosus ductus arteriosus patent foramen ovale

21

in pphn, minimal blood flow to lungs leads to...

hypoxia and acidosis

22

two phases of ductus arteriosus closure

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

23

ductus venosus

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

23

from the left ventricle the highest oxygen blood goes...

through ascending aorta to brain!

26

in utero, relative resistances?

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

27

what causes production of NO?

increased pO2 after fetus breathes