A 72-year-old male (60 kg) is receiving assist/control volum…

A 72-yeаr-оld mаle (60 kg) is receiving аssist/cоntrоl volume-control ventilation with VT 500 mL, rate 14/min, PEEP 8 cmH₂O, and FiO₂ 0.60. Breath sounds are diminished at the lung bases. Arterial blood gases are: pH 7.41, PaCO₂ 39 mmHg, PaO₂ 80 mmHg, SaO₂ 96%. Which action should the respiratory therapist take?