A 58-year-old man with a 40-pack-year smoking history presents with progressive dyspnea and stridor over 3 weeks. Flexible laryngoscopy reveals a large exophytic mass involving the anterior two-thirds of the vocal cords, with significant subglottic extension. Biopsy confirms squamous cell carcinoma. CT chest shows no distant metastases. The patient is scheduled for total laryngectomy with adjuvant radiotherapy. Before surgery, the anaesthetist expresses concern about securing the airway intraoperatively due to the mass location. What is the most appropriate immediate management?