“Hypoxic pulmonary vasoconstriction is a physiological phenomenon in which pulmonary arteries constrict in the presence of hypoxia (low oxygen levels) without hypercapnia (high carbon dioxide levels), redirecting blood flow to alveoli with a higher oxygen content.” Wikipedia
Why is hypoxic pulmonary vasoconstriction important to know? Well, think of a chronic smoker with COPD or core pulmonale etc that is having some swelling in his feet and SOB. Besides stopping smoking, what is the best treatment for this patient’s cor pulmonale and pulmonary HTN? Continuous low-flow oxygen. Why? It will reverse the pulmonary vasoconstriction caused by chronic hypoxia! You should put these patients on continuous low-flow oxygen!