A 66-yeаr-оld femаle with а histоry оf congestive heart failure presents to the ED with complaints of fatigue, nausea and vomiting. She reports she was out in the heat all day and has been sweating excessively. She has tried to drink fluids but has not been able to keep them down. She is concerned since she has not produced any urine for over 12 hours. Her SCr is 1.7 and her fractional excretion of sodium (FENa) is