Soru

Emergency medical services bring a 69-year-old retired teacher to the resuscitation bay due to three days of worsening respiratory distress. She reports an increase in sputum production that has become dark yellow. Her medical history is significant for hypertension, diet-controlled type 2 diabetes, and a 45-pack-year smoking history.

On physical examination, she is alert and cooperative but visibly exhausted, sitting on the edge of the stretcher and leaning forward on her arms. Temperature is $37.4^\circ\text{C}$ ($99.3^\circ\text{F}$), pulse is $112/\text{min}$, respirations are $28/\text{min}$, and blood pressure is $155/88\text{ mm Hg}$. Pulse oximetry shows an oxygen saturation of $85\%$ on room air. Jugular venous pulsation is visible $4\text{ cm}$ above the sternal angle. Chest auscultation reveals a prolonged expiratory phase with diffuse polyphonic wheezes and faint basilar crackles. Mild bilateral pitting edema is present at the ankles.

An electrocardiogram shows sinus tachycardia with right axis deviation and peaked P waves in lead II. A chest radiograph demonstrates hyperinflated lung fields, flattened hemidiaphragms, and enlarged central pulmonary arteries without focal consolidation.

Relevant laboratory results are as follows:

Which of the following is the most appropriate next step in the management of this patient?