Hold your breath for this one! The Curious Clinicians answer a puzzling pulmonary physiology question: Why can systemic pulmonary vasodilators worsen hypoxemia in COPD-associated pulmonary hypertension? Watch this episode on our new YouTube channel here, and read the show notes here! Click here to obtain AMA PRA Category 1 Credits™ (0.5 hours), Non-Physician Attendance (0.5 hours), or ABIM MOC Part 2 (0.5 hours). Audio edited by Clair Morgan of Nodderly.com. Medical student Giancarlo Buonomo is our producer.