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27 Cards in this Set
- Front
- Back
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What are the blood volume and blood viscosity changes that occur during pregnancy?
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Total blood volume up 40%
plasma volume up 50% RBC volume up 30% Hematocrit down 2-3% (physiological anemia) |
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What are the heart/function changes seen during pregnancy?
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Increased resting CO (up 30-70%)
Increased SV (due to increased vascular volume) increased HR Frank-starling improvement in performance due to increased ventricular volumes |
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What kind of cardiac remodeling takes place during pregnancy?
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there is a major increase in Left Ventricle Mass (up to 30% later in pregnancy)
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How does resistance and BP change during pregnancy?
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Systemic Vascular resistance decreases by up to 50% (due to a low resistance placental circulation, and estrogen levels)
BP- MAP drops till mid pregnancy, then returns to normal. (decreased MAP due to decreased TPR) |
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Where does gas exchange occur for the fetus?
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in the placenta
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how do the left and right sides of the heart work to pump in a fetus?
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these work in parallel
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What carries oxygenated blood from the placenta to the fetus?
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the umbilical vein
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what carries wastes from fetus to the placenta?
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umbilical arteries
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What organs does the placenta perform the functions of?
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Lungs
GI Liver Kidneys |
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What does the ductus venosus do?
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this shunts blood from the Umbilical vein into the IVC.
allows blood from placenta to bypass the liver (50% of blood) |
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what does the foramen ovale do?
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this is a RIGHT to LEFT shunt in the atria of the fetal heart.
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what does the ductus arteriosus do?
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this is a RIGHT to LEFT shunt,.
takes blood from the pulmonary artery and shunts it to the aorta |
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What is the resistance in the fetal lung like?
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it is high resistance
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what is the resistance like in the placentas vascular bed?
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this is low
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what is the CCO?
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this is combined cardiac output, it is the sum of the left and right sides of the fetal heart pumping together
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How much of the CCO does the ductus venous shunt? from where to where?
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this shunts 50% of CCO from the the umbilical vein into the IVC
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What is the fetal blood O2 sat when it enters the placenta?
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60% O2 sat
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what is the fetal blood O2 sat when it returns to the IVC from the placenta (via ductus venous)
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85% O2 sat
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What is the major change that leads to the establishment of pulmonary circulation?
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during birth, the first breath expands the lungs and cases a Decrease in Pulmonary Resistance
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What cardiovascular changes does removal of the placenta trigger?
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a large increase in total peripheral resistance
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What are the first changes that occur when the first breath is taken?
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Relaxing of pulmonary precapillary vessels by O2
Decrease in pulmonary pressure and resistance Increased blood flow in pulmonary circuit |
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What happens to circulation when the foramen ovale closes?
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Increase in LA pressure
LA pressure exceeds RA pressure Foramen Ovale is closed |
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What does cutting the umbilical cord do to fetal cardiovascular system?
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this decreases venous return to RA
reduces atrial pressure ductus venosus closes, resistance in system increases venous return decreases, decreasing RA/LA pressure |
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What happens when the pulmonary pressure falls below the aortic pressure?
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the flow through the ducuts arteriosus is reversed, now a left to right shunt
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what cause an atrial septal defect? what happens?
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this is caused by a failure of the foramen ovale to close.
produces a LA to RA shunt, dilated RA/RV, and pulmonary hypertension |
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what does a ventricular septal defect cause?
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this is a LV to RV shunt, provides more blood to lungs
pulmonary hypertension increased blood return to LA, leads to left heart remodeling |
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what does a patent ductus arteriosus do?
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this causes a L-R shunt, flowing from the aorta to the pulmonary artery
LV and LA are overloaded due to increased blood volume |
