Yоu аre а respirаtоry therapist assigned tо the ICU of a local hospital and have been called to assess a patient who may require mechanical ventilation. Physical examination reveals a respiratory rate of 25, blood pressure 145/90, pulse 115, and breath sounds are bilaterally decreased, especially in the bases. The arterial blood gas reveals: pH 7.44 PaCO2 36 mm Hg PaO2 42 mm Hg SaO2 70% HCO3 − 22 mEq/L Device: a nonrebreather mask at 10 L/min The patient’s maximal inspiratory pressure is –75 cm H2O, VC is 70 mL/kg, and VT is 7 mL/kg.