A respiratory therapist is caring for a patient who has ARDS…

A respiratory therapist is caring for a patient who has ARDS.  Blood pressure is 90/60 mm Hg on Vasopressin.  The patient is receiving PC, A/C ventilation with the following settings:   FIO2      1.0  Mandatory rate    20  PIP   30 cm H2O  PEEP    16 cm H2O    ABG analysis shows the following:   pH       7.36  PCO2     44 mm Hg  PO2     50 mm Hg  HCO3-     25 mEq/L  BE      -1 mEq/L  SO2 (calc)     82%    A chest radiograph shows bilateral lower lobe infiltrates.  Which of the following should the therapist do?