Soru

Emergency medical services bring an $81$-year-old woman to the hospital after she awoke gasping for air. Her daughter reports that the patient has been sleeping in a recliner for the past week due to a persistent nighttime cough and an inability to lie flat. Past medical history includes long-standing hypertension, diet-controlled type 2 diabetes mellitus, and a $40$-pack-year smoking history, though she quit a decade ago. A recent outpatient laboratory report from two days ago shows a thyroid-stimulating hormone (TSH) level of $1.2\ \mu\text{U/mL}$ (normal: $0.4\text{-}4.0\ \mu\text{U/mL}$) and a free thyroxine (T4) level of $0.5\ \text{ng/dL}$ (normal: $0.9\text{-}1.7\ \text{ng/dL}$). Upon arrival, the patient is visibly anxious, using accessory muscles of respiration, and unable to speak in full sentences. Vital signs show a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure of $182/105\ \text{mm Hg}$, pulse of $115\ \text{beats/min}$, and respirations of $28\ \text{breaths/min}$. Pulse oximetry reveals an oxygen saturation of $86\%$ on ambient air. Physical examination demonstrates distended jugular veins when sitting upright. Auscultation of the chest reveals diffuse bilateral crackles extending to the apices, accompanied by scattered expiratory wheezes. Cardiac auscultation reveals a regular tachycardia with a prominent extra heart sound occurring just after $S_2$. The lower extremities show $2+$ bilateral pitting edema to the knees. Arterial blood gas analysis on room air demonstrates a pH of $7.48$, a $p\text{CO}_2$ of $31\ \text{mm Hg}$, and a $p\text{O}_2$ of $54\ \text{mm Hg}$. Which of the following is the most appropriate initial step in the management of this patient?