Cardiovascular Physiological Changes During Pregnancy Flashcards
Cardiac output increases by ___________ during pregnancy
40 %
The uterus receives _______ of the cardiac output
10%
How does uterine contraction affect cardiac output
Uterine contraction causes autotransfusion resulting in increased preload
Heart rate increases by ______ during pregnancy
15 %
Stroke volume increases by ________
30 %
How is CO affected during the various stages of labor
- 1st stage: 20% increase
- 2nd stage: 50% increase
- 3rd stage: 80% increase
CO returns to pre labor values in _______ hours
24-48 hrs
CO returns to pre-pregnancy values within?
Approximately 2 weeks
How does a twin pregnancy affect cardiac output
It increases CO above a single fetus pregnancy
How is MAP affected in pregnancy
no change
How is SBP affected in pregnancy
No change
How is DBP affected
DBP decreases by 15%
MAP remains unchanged in spite of Increased cardiac output because?
^Blood volume + Decreased SVR = Net even effect on MAP
How is SVR affected
15% decrease
How is PVR affected
30 % decrease
Why is vascular resistance decreased
- Progesterone causes Increased nitric oxide causing vasodilation.
- Progesterone causes decreased response to angiotensin and NE
What is the effect of pregnancy on filling pressures (CVP and PAOP)
No change, however uterine contractions causes autotransfusion and can increase filling pressures.
How does pregnancy affect the cardiac axis?
Left deviation: Heart is pushed up and left
Identify the three major actions of progesterone
- Increases RAAS activity => ^blood volume => Increased cardiac output
- Vascular relaxation => Decreased SVR and PVR => Increased blood flow
- ^Minute ventilation Vt>RR => Decreased PaCO2 => Kidney elimination of HCO3 to preserve pH
syndrome of supine hypotension is also called?
Aortocaval compression
Aortocaval compression causes compression of?
Both the aorta and the vena cava
Aortocaval compression results in what effects?
- Decrease venous return to the heart as well as arterial flow to the uterus and lower extremities.
- Decreased CO compromises fetal perfusion and can lead to maternal loss of consciousness
Aortocaval compression results in what effects?
- Decrease venous return to the heart as well as arterial flow to the uterus and lower extremities.
- Decreased CO compromises fetal perfusion and can lead to maternal loss of consciousness
Aortocaval compression is prevented by? This should be perform at what stage of pregnancy?
Prevented by 15 degrees left uterine displacement.
Should be performed on anyone that is in their second or 3rd trimester.
