If the patient is on a ventilator oral care should be done according to AACN recommendations to prevent VAP. IT should make no difference as to the route of ventialtion (ETT Trach Nasal). I encourage you to check out the AACN website practice alerts on oral care. It doesn't address your specific question with regard to ETT vs trach, but it gives current guidelines with great evidence to back it up. You don't need to be a member to look at the site, but you do need membership to access other databases.