Conventional Oxygen Therapy Versus Continuous Transnasal High Flow Oxygen Therapy for Head and Neck Diagnostic Panendoscopy Under General Anesthesia in Spontaneous Ventilation

Inclusion Criteria:

* Patients suffering from a head and neck cancer, most often tumor of the bucco-pharyngo-laryngeal cavities, having to carry out a diagnostic HN panendoscopy;
* Patient over 18 years of age;
* ASA \< 4;
* BMI ≤ 45;
* Patient willing and able to provide written informed consent for the trial;;
* Patient affiliated with a health insurance system.

Exclusion Criteria:

* Patient with a contraindication to the Optiflow™ system as defined in the manufacturer's brochure;
* Patient with a tumor obstructing more than 80% of the glottic lumen;
* Patient with impossible intubation criteria:

  * Mallampati 4 and mouth opening less than 20 mm
  * Retrognathia
* Patient with:

  * A known intracranial pathology;
  * Documented pulmonary hypertension;
  * Uncontrolled epilepsy;
  * Uncontrolled heart rhythm disorder;
  * Pulmonary pathology with hypoxemia: Spo2 \<92% in ambient air;
* Patient at high risk of a full stomach evaluated by the anesthetist;
* ASA ≥ 4
* Morbid obesity with BMI\> 45;
* Obstructive upper airway tumor with functional impact;
* Known contraindication to propofol or alfentanil;
* Panendoscopy procedure to be combined with an oesogastro-duodenal fibroscopy;
* Vulnerable persons as defined by articles 64 and 68 of Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices :

  * In the case of incapacitated subjects who have not given, or have not refused to give, informed consent before the onset of their incapacity, a clinical investigation may be conducted only where, in addition to the conditions set out in Article 62(4)
  * Pregnant or breast-feeding women who do not fall under the provisions of Article 66
  * Adults subject to a legal protection order or unable to give their consent.