A 68-year-old male with COPD and severe kyphoscoliosis presents to the ICU with acute hypoxemic respiratory failure (SpO₂ 78% on 15 L/min O₂). On examination, the patient has a short neck, limited neck extension, and a Mallampati score of IV. After failed bag-mask ventilation and a single failed intubation attempt by the senior resident, the patient's SpO₂ drops to 62%. What is the most appropriate next step in management?