A 40-year-old woman with severe ARDS is being ventilated with TV 6 mL/kg IBW (360 mL), PEEP 16 cmH2O, FiO2 0.8, RR 28/min. Plateau pressure is 29 cmH2O. ABG: pH 7.18, PaO2 9.0 kPa, PaCO2 9.5 kPa, HCO3 21 mmol/L, lactate 1.5 mmol/L. She is prone. Heart rate 95 bpm, MAP 72 mmHg on noradrenaline 0.15 mcg/kg/min. Which strategy is most appropriate for the hypercapnia?