cna is the lowest and they are certified nursing aides. a cna is a person who assists patients or clients with healthcare needs under the supervision of a registered nurse (rn) or a licensed practical nurse (lpn). some of their duties include: answer patients' call signals. turn and reposition bedridden patients, alone or with assistance, to prevent bedsores. observe patients' conditions, measuring and recording food and liquid intake and output and vital signs, and report changes to professional staff. feed patients who are unable to feed themselves. provide patients with help walking, exercising, and moving in and out of bed. provide patient care by applying dressings and supervising exercise routines. prepare patients for surgery, treatment, or examination. transport patients to treatment units, using a wheelchair or stretcher. clean rooms and change linens. http://en.wikipedia.org/wiki/certified_nursing_assistant lpn is above a cna but below an rn. licensed practical nurse. they usually report directly to physicians and rns, and are usually responsible for taking vitals and monitoring in-and-out volumes, treating common like bedsores, and preparing or performing several procedures such as dressing wounds, bathing and dressing, and giving enemas. http://www.studentdoc.com/nursing-job-description.html