A patient with RDS has alveolar hypoxia and pulmonary vasoconstriction. How will this affect his blood flow?
1) Blood shunts through the foramen ovale
2) Increased systemic blood flow
3) Blood shunts through the ductus arteriosus
4) Decreased blood flow to the gut

Question

Quizplus · Accepted Answer

In the context of RDS (Respiratory Distress Syndrome), alveolar hypoxia leads to pulmonary vasoconstriction, which in turn increases pressure in the pulmonary artery. This can cause a right-to-left shunt through the ductus arteriosus (3) and potentially through the foramen ovale (1) if the pressure in the right atrium exceeds that in the left atrium, directing blood away from the lungs. This mechanism does not directly increase systemic blood flow (2) or specifically decrease blood flow to the gut (4).

A Patient with RDS Has Alveolar Hypoxia and Pulmonary Vasoconstriction