You are caring for a 2 month old with sepsis in the PICU on…

You are caring for a 2 month old with sepsis in the PICU on broad spectrum antibiotics and vasopressors. You have been monitoring this patient closely for AKI. On his morning labs you note that the serum creatinine has increase from 0.5 to 1.1 and his urine output has decreased to 0.5ml/kg/hr for the last 18 hrs. What stage of AKI is the patient in?