When the fetal shunt between the pulmonary artery and the aorta ...

[abarnes]

When the fetal shunt between the pulmonary artery and the aorta fails to close after birth, or reopens after closure has occurred, it is known as:
 
  a. Congestive heart failure
  b. Patent ductus arteriosus
  c. Bronchopulmonary dysplasia
  d. Intraventricular hemorrhage

Question 2

Prolonged periods of hyperoxygenation that cause retinal vasoconstriction are known as:
 
  a. Intraventricular hemorrhage
  b. Glaucoma
  c. Cataracts
  d. Retinopathy of prematurity

[sierramartinez]

Answer to Question 1

ANS: B
The fetal shunt between the pulmonary artery and the aorta is the ductus arteriosus. Because of the underdeveloped musculature or hypoxia, there may be an incomplete closure of the ductus arteriosus (patent ductus arteriosus PDA) in the preterm newborn. When the ductus remains open, left-to-right shunting of the blood in the heart occurs because of the added load placed on the left ventricle of the heart. This results in pulmonary congestion and increased hypoxia.

Answer to Question 2

ANS: D
Prolonged periods of hyperoxygenation (partial pressure of oxygen PaO2 levels greater than 90 to 100 mm Hg) can be dangerous to the newborn because the condition produces oxygen toxicity. Oxygen toxicity can cause vasoconstriction and leakage in the vessels of the retina and retinal detachment, resulting in retinopathy of prematurity (ROP), previously called retrolental fibroplasia, which can lead to loss of vision or blindness.