Mаrgаret Chen, а 78-year-оld female, presents tо the ED with a 4-day histоry of productive cough, fever (101.8°F), dyspnea, and fatigue. Past medical history includes hypertension and a 40-pack-year smoking history (quit 10 years ago). Vital signs: HR 102, RR 28, BP 148/86, temp 101.8F, SpO₂ 88% on room air Ms. Chen is admitted for community-acquired pneumonia. Sputum and blood cultures were obtained before starting broad-spectrum antibiotics. Oxygen therapy initiated via nasal cannula at 4 L/min, maintaining SpO₂ 92%. Hydration and nutrition support begun. Early mobility encouraged within tolerance. She has a DNR and DNI. Deterioration - Day 2:Despite antibiotic therapy, Margaret's respiratory status worsens. Oxygen requirements increase to high-flow nasal cannula at 6 L/min. Bilateral infiltrates now visible on chest X-ray. ABG shows worsening hypoxemia (PaO₂ 58 mmHg on high-flow oxygen). At shift change, Margaret develops severe respiratory distress. She becomes increasingly hypoxemic despite oxygen at 15L via NRB. What is the next intervention you would recommend?