Tegrity, Tegrity, Tegrity...I listened constantly. I played it while doing housework,,,I put it on an IPOD and listened while commuting. You'll hear something every time that you missed before. Also, read up on ABGs,,,go to nursing journals and online and get a grip on the concept. They gave us the ROME nuemonic (sp?),,it helps a lot, but the lecture was the pits,,,no help at all,,I learned it on my own. If you know anyone in NAC I now, get their lectures and download them and start listening ASAP....I learned a lot, but there is so much information that it took me several times listening to get it all. ( I don't think you can get it "all", but most). Good Luck !