I understand that we bladder scan in order to check the post void residual urine in the bladder. So on the ward yesterday I was working with a nurse who was bladder scanning an elderly patient as he was not voiding very much. It showed up 550 mls. There was nothing done, she just took note of the volume and documented it. What do you do when you discover the patient has a large residual volume. I know he urinated later, but what would we do if he didn't? Can someone explain this to me. The patient is confused also so I guess he doesn't always know when he needs to void and maybe that is why he is retaining that amount?