I've worked in an 18 bed general ICU for a year now, and we deal with a little bit of everything. Most of the patients assigned to me as a newer nurse in the unit have had diagnoses of sepsis/SIRS/MODS, pneumonia/ARDS/respiratory failure, DKA, acute renal failure, MI (post cath lab overnight observation), or symptomatic EKG abnormalities. I've also had quite a few trauma patients (GSWs, MVAs- lots of chest tubes). Familiarize yourself with ACLS, rhythms and drips (nitro, cardizem, levophed, dopamine, etc.), sepsis protocol, vents, etc. If you have a high population of ARF patients, brush up on CRRT. Also, in the critical care environment, it is so important to be familiar with your state's Nurse Practice Act. Physicians will ask you to do things that are not in your scope of practice in emergencies! Protect your license.