3 High-Yield Paradoxes: COPD, warfarin, carbon monoxide

Here are a few counterintuitive fun facts that almost always come up on the USMLE:

Oxygen can worsen respiratory failure in COPD

Warfarin increases clotting risk before preventing clots

Carbon monoxide (CO) poisoning causes hypoxia but increases SpO₂

These topics trip a lot of students up, but once you remember they're the opposite of what they seem, they'll be easy points on your exam.

Published: March 19, 2025

Ryan Phelps, MD

Founder & CEO at Ora AI