Flashcards in Fetal Circulation Deck (12)
Describe the fetal circulation.
Oxygenated - Umbilical vein - IVC, FO, LA, LVC Aorta
Deoxygenated - SVC and IVC flows through RA, RV, PA, DA, Descending aorta
What is streaming?
Directs oxygenated blood at FO
Why are the feta lungs different antenatally?
Fluid filled and collapsed therefore very high resistance
What does the ductus arteriosus do?
Blood from PA -> Aorta
Relationship BP vs GA
RV pressure vs GA. LV vs RV? Atrial pressures?
Atrial pressures of 0 - 4 mmHg, no change related to GA
How much blood goes to the lungs in the fetus?
How is volume flow distributed L v R in fetus?
Slight RV dominance 1.2:1
How is the fetal circulation assessed?
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
What is the effect of increased pulmonary blood flow?
Due to reduced PVR.
Closes FO. Increases LA pressure.