I used the Kaplan CCRN review book to study and took a AACN review course which you can find near you on their website. I have actually never worked in ICU other than a 6 month ICU preceptorship my senior year of school. I tried staying up to date on ICU type stuff and I work in cardiac surgery step down for the past 1.5 years.
There was a lot of "what is the nurses best response" questions and ones about the synergy model. Had to know my norms for my hemodynamics and which shock states did what to the numbers. I had no pictures or rhythm interpretations although I heard some people can have these.
Best part was you can flag questions to go back to. I did this because as the test went on I relaxed a bit and remembered more info.
I've only been a nurse for a year and a half but you have to make sure you get your hourly requirements in order to take test. I don't remember any select all that apply questions but there were answers with multiple answers in them such as decrease CVP decreased SVR etc. all in one answer.