Participants do not accept hypnosis.

Tracheotomy is requested when upper aero-digestive tracts are obstructed. This obstruction can have a tumour, infectious, inflammatory, traumatic or nervous origin. Most tracheotomy surgeries are performed for tumour-induced obstruction. Tracheotomy allows the setting of a respiratory flux thanks to a cannula and excludes the upper airways. The cannula is washed every day from once to several times depending on the patient's secretions production and it is usually replaced every week. The second replacement takes place about 10 days after surgery. Patient education takes place at every replacement in order to empower him/her and in consequence to increase living comfort. This empowerment is achieved at the 4th or 5th replacement, at best. Because of the risks and complications related to tracheotomy and because of the concerned vital function, the cannula replacement leads to anxiety especially during the first replacements. Usual patient's anxiety management consists in reassuring the patient during the replacement. In other situations, patients' anxiety management would be drugs, however due to sedative and anxiolytic drugs' adverse events and to the need to maintain optimal breathing, they are not used in first intention. Our choice is to use conversational hypnosis during cannula replacement as it has already demonstrated interesting effects in pain and anxiety. Conversational hypnosis does not present an induction phase like in so-called hypnosis, it aims at leading the patient to perceive his/her world differently with only a slight consciousness alteration.

Once the informed consent form is signed and when the cannula replacement has to be performed, conversational hypnosis session will start right from the patient's room entrance and end when the nurse will come out. The care will consist in aspiration, cleaning and finally replacement of the cannula. Adverse events are expected to be related to the cannula replacement itself: patients will be followed-up during a maximum of 7 days with one follow-up visit which will take place 2 hours after cannula replacement and a second one which can take place from the day after the replacement up to just before the following replacement.

Inclusion Criteria:

• patients hospitalised in the Ear, Nose, Throat - specialties surgery department
• aged of 18 years old and more
• having a tracheotomy following an upper aero-digestive tracts obstruction
• presenting a tracheal cannula which can be replaced by paramedical staff
• able to communicate to give their consent
• member or beneficiary of a social security assurance
• having given a signed informed consent form

Exclusion Criteria:

• patients presenting a hearing loss (preventing from hearing properly the words pronounced during conversational hypnosis)
• who do not understand French
• who are under curators/guardianship
• presenting dementia
• autonomous in their cannula replacement
• having already participated in the study