Question

A 42-year-old man is brought to the emergency department by his friends due to unresponsiveness. They report that he consumed a large amount of alcohol at a party before becoming stuporous and vomiting profusely. On initial arrival, the patient is difficult to arouse but is protecting his airway. His vital signs are stable, and he is placed in a lateral decubitus position for observation. Two hours later, he develops sudden respiratory distress. Temperature is $37.9^\circ\text{C}$ ($100.2^\circ\text{F}$), blood pressure is $130/80\text{ mmHg}$, pulse is $110\text{/min}$, and respirations are $26\text{/min}$. Pulse oximetry shows an oxygen saturation of $88\%$ on room air. Physical examination reveals diminished breath sounds and crackles in the right lower lung field. Leukocyte count is $14,500/\mu\text{L}$. A chest radiograph demonstrates patchy alveolar opacities in the right lower lobe. Which of the following is the most appropriate next step in management?