A 72-year-old man presents to the emergency department with persistent vomiting, inability to eat or drink for 2 days, and severe back pain. He has been taking ibuprofen (800 mg three times daily), lisinopril for hypertension, and aspirin for stroke prevention. He reports diminished urine output of 200 mL over the last 24 hours. Vital signs: Temperature: 98.8 °F Heart rate: 162 bpm Respiratory rate: 17 bpm Blood pressure: 90/55 mmHg Oxygen saturation: 97% on room air The patient has multiple risk factors for prerenal azotemia. Which of the following urine findings is most likely in this patient?
