Cardio - case study 16

Question 1

Why does increased pulmonary vascular resistance cause pulmonary hypertension?

Answer 1

blood packed up as resistance to blow flow increased - increased blood volume caused increased pressure

Question 2

How is pulmonary vascular resistance calculated?

Answer 2

pulmonary artery pressure - left atrial pressure / cardiac output

Question 3

What is the afterload?

Answer 3

the pressure against which the ventricles must eject blood - in this case, blood backup would increase the afterload and cause right ventricular failure

Question 4

What is the meaning of an audible fourth heart sound?

Answer 4

blood flow produces a sound due to a less compliant ventricle

Question 5

Why is ascent to a high altitude contraindicated with pulmonary hypertension?

Answer 5

barometric pressure is decreased, resulting in decreased partial pressure - she would have breathed air with a lower PO2, which would have lead to vasoconstriction in pulmonary circulation, further elevating her pulmonary vascular resistance, and increased the afterload on her right ventricle