A 34-yeаr-оld femаle whо is а victim оf a residential fire is brought to the ED and is receiving oxygen by nasal cannula at 4 L/min. SpO2 is 100%. The following data are observed: pH 7.31 SO2(meas) 99% PCO2 32 mm Hg O2Hb 78% PO2 205 mm Hg COHb 21% HCO3 - 16 mEq/L Hb 14.5 g/dL BE -9 mEq/L A respiratory therapist should recommend