A middle-aged woman presents with breathlessness, fatigue, and infrequent urination. Her skin appears pale and bruised. The most appropriate initial investigation is to check her urea and electrolytes. A man diagnosed with AKI has diarrhea, vomiting, and loss of appetite. He has oliguria and high potassium. The first step in his management should be to treat his high potassium. All of the options are indications for dialysis in a patient with chronic renal failure except pericarditis.