Question

A 62-year-old woman with a history of chronic obstructive pulmonary disease (COPD) presents to the emergency department complaining of progressive shortness of breath over the past three days. She reports an increased frequency of cough and a change in her sputum from clear to thick and yellow-green. She denies chest pain, orthopnea, or paroxysmal nocturnal dyspnea. Her daily medications include a long-acting muscarinic antagonist and a short-acting beta-agonist as needed. Vital signs are temperature $37.8^\circ\text{C}$ ($100.0^\circ\text{F}$), blood pressure $135/85\text{ mmHg}$, heart rate $108\text{/min}$, and respiratory rate $26\text{/min}$. Oxygen saturation is $86\%$ on room air.

Physical examination reveals a patient in moderate respiratory distress, using accessory muscles of respiration. Auscultation demonstrates a prolonged expiratory phase and diffuse end-expiratory wheezing bilaterally. Cardiac examination shows a rapid, regular rhythm with no murmurs, gallops, or jugular venous distention. There is no peripheral edema.

Chest radiograph shows hyperinflated lung fields with flattened diaphragms, but no focal consolidations or pleural effusions.

Arterial blood gas on room air reveals:
pH: $7.28$
$\text{PaCO}_2$: $66\text{ mmHg}$
$\text{PaO}_2$: $54\text{ mmHg}$
$\text{HCO}_3^-$: $30\text{ mEq/L}$

Which of the following are appropriate next steps in the management of this patient? (Select all that apply)