Last week our ED registrars hosted a really good day of education for their colleagues in the surrounding hospitals. I was asked to give a workshop on blood gas. During the MNSHA masterclass I enjoyed the discussion about arterial versus venous, and decided to share that with our colleagues-to-be. Just for starters, hope I made some of them curious enough to search for details. But I started with the alveolar gas equation, to explain how we can assess if the lungs are properly transferring oxygen into the blood. I have put my slides on our website so you can use them.