Comparison of Two Ventilation Methods During Endoscopy of the Pharynx, Larynx and Oesophagus

Overview

Around 15,000 ENT cancers are diagnosed each year in France. The majority of these cancers will at one time or another require an Endoscopy of the Pharynx, Larynx and Esophagus (Endo-PLE or suspension laryngoscopy). Endoscopies of the Otorhinolaryngeal (ENT) sphere are common procedures. They consist of inserting a rigid laryngoscope through the mouth, allowing full exposure of the laryngeal sphere. For all patients, these endo-PLE are performed in the operating room and require general anesthesia. This surgical procedure is now performed by performing two laryngoscopies. The first is used to maintain good pulmonary oxygenation by introducing an oxygen cannula, the second constitutes the surgical procedure itself. The oxygen cannula is placed through the nasal cavity, directly up to the entrance of the vocal cords. This procedure is not without risk both for the patient (risk of dental breakage and bleeding during laryngoscopy) but also for the surgeon, because the cannula itself can obstruct his vision. It would be possible to do without one of them by setting up high-flow oxygen therapy (HFOT). This device has been widely deployed in continuous care and intensive care units, but is not yet the subject of much research in surgical units. The HFOT consists of oxygen cannulae delivering a mixture of gases at a high flow rate ranging from 20 to 70 liters per minute. The investigator want to evaluate through this study, the feasibility and effectiveness of setting up HFOT during procedures.

Endoscopy of the pharynx, larynx and oesophagus (endo-PLO) is a diagnostic procedure that enables the anatomical structures that enable speech, breathing and swallowing to be visualised. By keeping the patient on spontaneous ventilation (SV) during this procedure, the anatomical structures can be better observed. The examination lasts an average of 45 minutes, from the time the patient enters the operating theatre until he or she leaves. Today, endo-PLO is performed using two laryngoscopies. Laryngoscopy involves inserting a curved piece of metal approximately 10 centimetres long into the patient's mouth, to expose the patient's vocal cords and insert a laryngeal device (oxygen probe, intubation probe) to enable the patient to be ventilated. As part of an endo-PLO, an initial laryngoscopy is carried out by the State-qualified Anaesthetist Nurse or Anaesthetist Resuscitator . This first laryngoscopy is used to instil a 2% lidocaine solution (3 ml) between the vocal cords via a local anaesthetic spray device, which helps to provide intra- and post-operative analgesia. In a second stage, this first laryngoscopy will enable an oxygen cannula to be introduced via the patient's nasal cavities to the entrance to the vocal cords. Once this first laryngoscopy has been performed, the anaesthetic is gradually lifted so that the patient regains VS while remaining unconscious. A second laryngoscopy (suspension laryngoscopy) is then performed by the surgeon to proceed with the operation. Once the procedure is complete, the nasal cannula is removed and the patient awakened in the operating theatre. In the case of ENT cancers, this tumour damage weakens the anatomical structures and encourages bleeding at the slightest contact. As with any procedure, there is a significant risk of damage to these anatomical structures during laryngoscopy. As the tissues of the laryngeal walls are very fragile, there is a major risk of bleeding, which may cause difficulties in carrying out the surgical procedure. High-flow oxygen therapy (HFOT) is a medical technology that has been in use for many years, particularly at Poitiers University Hospital. This device enables oxygen to be administered and delivered at flow rates ranging from 20 to 70 litres per minute (L/min), with the capacity to produce an inspired fraction of oxygen (FiO2) of between 21% and 100%. It consists of a gas mixer, connected to a heater and humidifier for comfortable, optimal delivery of the gas mixture. The heater keeps the inspired gases at an average temperature of 37°C, while the humidifier prevents the patient's airways from drying out. The gas mixture comes from two different connections, linked to an air and oxygen intake, to ensure that the FiO2 recorded is the same as that delivered to the patient.