A nurse has just started on the 7PM surgical unit shift. Which of the following patients should the nurse check on first?

C A 21 year-old male who had a lower extremity BKA yesterday, following a MVA and has phantom pain. A A 75 year-old female who is scheduled for an EGD in 10 hours. B A 34 year-old male who is complaining of low back pain following back surgery and has an onset of urinary incontinence in the last hour. D A 27 year-old female who has received 1.5 units of RBC's. via transfusion the previous day.