Sir, I have questions: S.C.D patient post CPR attached to ventilator SIMV mode with 100% O2, RR 14 TV. 500 ml. ABG done shows PaO2 410 mm Hg, O2 sat. 99% PaCO2 39 mm Hg, PH 7.42, HCO3 19 mEq/L. BE –2. Dr. advise to decrease his FIO2 according to the PaO2 result. How much you will decrease it? (Please write the role for O2 regulation).