APPLIED: CARDIOVASCULAR SYSTEM

These flashcards cover key concepts from the lecture on the cardiovascular system as it applies to midwifery, focusing on the structure, function, and physiological changes associated with the heart during pregnancy.

What is stroke volume (SV)?

The amount of blood leaving each ventricle during one contraction, normally around 70 ml.

How is cardiac output (CO) calculated?

Cardiac Output = Heart Rate x Stroke Volume.

What is the equation for blood pressure (BP)?

BP = cardiac output (CO) x peripheral resistance (PR)

What physiological changes occur in blood volume during pregnancy?

Total blood volume increases by 45-50% to meet the demands of pregnancy.

What is the effect of supine position on pregnant women?

It can cause supine hypotension due to compression of the inferior vena cava.

What is haemodilution in pregnancy?

It refers to the dilution of red blood cells due to an increase in plasma volume.

How does blood pressure change during pregnancy?

There can be a slight decrease in blood pressure, especially in the second trimester.

Name two anatomical changes in the cardiovascular system that occurs in pregnancy

• heart is pushed up

• Size increase (capacity increases by 70-80ml) but heart muscle stays the same

Name one way in which blood pressure changes in pregnancy

• slight decrease due to decrease in peripheral resistance

Name one haematological change in pregnancy

• Increase blood vessels

• Plasma increases by 45%

• Erythropoietin increase

How does lying in a supine position affect pregnancy?

• Inferior vena cava is compressed by the pregnant uterus

• decreases Venus return back to the heart

• Decreases cardiac output = causes drop in BP = faint and dizziness

• Also reduces blood supply = distressed fetus