Like so many threads before this one, I would suggest that you build your confidence in working with ICU patients, providers, pharmokinetics, hemodynamics, rhythms, etc. When you go for your interview know that you have the experience of being one step ahead of the providers orders. As an example, be professional but direct if a resident gives an order (such as a wrong dose for a drug) that you know is wrong for a pt in a given situation that you are familar with.
On your paper application, you will probably not stand out from the general application pool. Your GPA should be competitive. Your GRE should be around the mean. Additional science classes including organic chem, additional anatomy should highlight your profile. When you are invited for an interview, you should plan on selling yourself like you would in a job interview
. The interview committee has about 30 minutes to develop a thumb-nail sketch of who they think you are based on what you tell them. And don't be afraid to ask questions when you feel the interview allows. I hope this helps you.