Question

An obtunded $71$-year-old man is evaluated in the emergency department for acute, severe dyspnea and altered mental status. He has a past medical history of ischemic cardiomyopathy with a left ventricular ejection fraction of $35\%$, severe chronic obstructive pulmonary disease, and type 2 diabetes mellitus. He was evaluated at an outpatient clinic two days ago for a mild cough; a sputum culture from that visit is now resulting, showing *Haemophilus influenzae* susceptible to amoxicillin. The patient is accompanied by his estranged wife and his brother. The brother provides a legally binding document designating him as the patient's healthcare proxy. The wife demands that the patient be placed on a mechanical ventilator immediately, while the brother requests that medical therapies be optimized first before considering intubation.

Vital signs include a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure of $82/55\text{ mm Hg}$, pulse of $118/\text{min}$, and respirations of $28/\text{min}$. Oxygen saturation is $88\%$ on room air. Physical examination reveals a somnolent but arousable patient. The extremities are cool and clammy with faint peripheral pulses. Jugular venous pressure is elevated to $13\text{ cm H}_2\text{O}$. Lung auscultation demonstrates diffuse, high-pitched expiratory wheezes bilaterally without crackles. Cardiac auscultation reveals distant heart sounds with a regular tachycardia.

Laboratory results are as follows:
Leukocyte count: $11,500/\mu\text{L}$
Lactic acid: $4.8\text{ mmol/L}$
Thyroid-stimulating hormone: $1.2\text{ }\mu\text{U/mL}$ (Normal: $0.4-4.0\text{ }\mu\text{U/mL}$)
Free T4: $0.6\text{ ng/dL}$ (Normal: $0.9-1.7\text{ ng/dL}$)

A chest radiograph reveals an enlarged cardiac silhouette with prominent upper lobe vasculature and no focal consolidations. Which of the following is the most appropriate next step in the management of this patient?