A 3-yeаr оld оn mechаnicаl ventilatiоn for PARDS is being monitored with ABG and pulse oximetry. The PaO2 is 72 mmHg on FiO2 0.60, SpO2 is 94% and PaCO2 is 45 mmHg. Which strategy best reflects appropriate ongoing management of invasive and non invasive monitoring?