Can a critical care nurse work in a trauma unit?

Usually. Check with hr or the unit director.
Yes. Most icu's have the capacity to handle trauma and critical care nurses usually have plenty of experience managing these patients. There are some icu's that specialize specifically in trauma, but they also use critical care nurses.
CCRN in trauma unit. Yes...A trauma unit, such as a trauma ICU or a sicu utilizes many nurses who have added qualifications, such as a ccrn certificate.