I believe it is too soon to be craming for the CCRN you need to work on your critical thinking skills and your technical skills. There is alot of knowledge needed to pass CCRN The best book I used was BY Laura Gasparis critical care review examination it is a book of just questions but the answers are detailed why the one is right and why the others are wrong. I waited 3 years into ICU to try for the CCRN. I learned time management and critical thinking skills first. THe test covers alot of 12 lead, Hemos and abg's with Vent changes GOOD LUCK whenever you take it