CCRN does not stand for critical care registered nurse. please see the aacn website for detailed information pertaining to the ccrn certification. ccrn stands for certified critical care registered nurse. to say that you are a critical care registered nurse implies that you have been " registered" as a critical care nurse. this is not true. you have been " certified" as a critical care nure. there is a huge difference. please see the aacn website for details.