A 35-year-old woman is admitted 8 hours after a tibia fracture sustained in a fall from height. She develops severe leg swelling, pain on passive toe extension, and compartment pressure measured at 38 mmHg (diastolic BP 65 mmHg). She undergoes urgent fasciotomy. Over the next 24 hours, she develops dark urine, a serum creatinine rise from 0.9 to 2.8 mg/dL, and serum potassium of 6.2 mEq/L. What is the most appropriate immediate intervention to prevent acute kidney injury?