An 80-Year-Old Female with a Diagnosis of Pneumonia Was Admitted

An 80-year-old female with a diagnosis of pneumonia was admitted to the hospital 2 days ago from a nursing home.The patient is responsive only to painful stimuli.She has a peripheral IV and a feeding tube in place.Physical examination reveals: pulse 98 beats/min; respiratory rate 24 breaths/min and shallow; blood pressure 100/48 mm Hg; and temperature 39.2° C.Auscultation reveals decreased breath sounds with crackles in the bases.The patient has an occasional weak,nonproductive cough.Arterial blood gas on NC 4 L/min is pH 7.42,PₐCO₂ 38 mm Hg,PₐO₂ 40 mm Hg,SₐO₂ 76%,HCO₃⁻ 24 mEq/L.A portable chest X-ray shows patchy basilar infiltrates in both lungs.The most appropriate action to take at this time is which of the following?

A) Intubate and initiate mechanical ventilation.
B) Administer a bronchodilator and mucolytic.
C) Initiate noninvasive positive pressure ventilation.
D) Change the nasal cannula to a nonrebreather mask.