There may be signs of fluid overload, including abnormal sounds on listening to the heart and lungs with a stethoscope (auscultation ).Other signs include:BUN and serum creatinine levels may increaseFractional excretion of sodium and of urea may be relatively highKidney biopsy may show acute tubular necrosis (but a biopsy is rarely done)Urinalysis may show casts , kidney tubular cells, and red blo