The concept of taking blood out of the body, oxygenating it, removing the CO2, and then putting back in, fascinates me. A few years ago I admittedly knew very little about extracorporeal membrane oxygenation (ECMO) and its indications. I remember going to a class on ECMO at Life Link III and having questions like:   Are we actually pumping blood backward through the body?   What happens to the blood in the heart when using ECMO in cardiac arrest (ECPR)?   What kind of vent settings should I use?   I am by no means an expert on ECMO, in fact, I have only been on a handful of ECMO transports, but the concept fascinates me and I thought a blog breaking down a few concepts of ECMO physiology would be beneficial.