Inclusion Criteria:  All patients hospitalized in the Lausanne ICU between May 1st 2017 and November 31st 2018 with a tracheotomy and mechanically ventilated more than 72 hours.  Exclusion Criteria:  Presence of a know opposition to participation to research projects Patient tracheostomized specifically for ENT (ear-nose-throat) reason Burn victim Patient tracheostomized before his/her admission to the Lausanne ICU