Nurses in critical care or the ICU unit must be Registered Nurses. This RN is best served with a BSN, or a Bachelor’s of Science in Nursing, although some RN’s begin with an Associate Degree in Nursing. The critical care nurse provides intensive and constant care for patients whose lives are in danger, whether by accident or illness. Intensive care nursing is a demanding profession requiring long hours and commitment to the job. The ability to adapt rapidly to changing circumstances is another requirement for Critical Care/ICU nurses. A Critical Care/ICU nurse must be able to emotionally detach from the situation and remain calm when things change rapidly. It is not unusual for an ICU nurse to deal with the loss of patients on a somewhat regular basis.