A 55-year-old woman with KDIGO Stage 3 AKI secondary to sepsis is on ICU. She is haemodynamically unstable on noradrenaline 0.3 mcg/kg/min. Potassium is 6.8 mmol/L with ECG changes (peaked T waves, widened QRS). pH 7.15, HCO3 12 mmol/L, lactate 5.0 mmol/L. She is anuric. What is the most appropriate renal replacement therapy modality?