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Flashcards in Fetal Circulation Deck (12)
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1

Describe the fetal circulation.

Oxygenated - Umbilical vein - IVC, FO, LA, LVC Aorta

Deoxygenated - SVC and IVC flows through RA, RV, PA, DA, Descending aorta

2

What is streaming?

Directs oxygenated blood at FO

3

Why are the feta lungs different antenatally?

Fluid filled and collapsed therefore very high resistance

4

What does the ductus arteriosus do?

Blood from PA -> Aorta

5

Relationship BP vs GA

Positive

6

RV pressure vs GA. LV vs RV? Atrial pressures?

Positive.

Equal pressures.

Atrial pressures of 0 - 4 mmHg, no change related to GA

7

How much blood goes to the lungs in the fetus?

17%

8

How is volume flow distributed L v R in fetus?

Slight RV dominance 1.2:1

9

How is the fetal circulation assessed?

Ultrasound

10

What changes at birth?

PVR decreases dramatically.

FO and DA close.

Placenta gone, therefore R heart seeing decreased pressures and L heart seeing increased afterload/resistance

11

What is the effect of increased pulmonary blood flow?

Due to reduced PVR.

Closes FO. Increases LA pressure.

12

Why does the arterial duct close?

Inhibition of PGE synthesis