A 42-year-old woman with morbid obesity (BMI 48 kg/m²) and a short neck is scheduled for emergency cesarean section under general anesthesia. After induction with propofol and succinylcholine, the anesthesiologist attempts bag-mask ventilation but finds it increasingly difficult to maintain adequate ventilation. The SpO₂ drops from 98% to 89% within 2 minutes. The resident suggests applying higher positive airway pressure (PAP) to improve ventilation. What is the most appropriate next step in managing this difficult bag-mask ventilation scenario?