In our unit, we use T-pieces to deliver humified oxygen to a long term ventilated patient who is being weaned from the ventilator. We generally do first day 1-2 hours t-piece, then 2 hrs ventilator, and continue that for the day as tolerated, and then back onto pressure support for the night. The second day, if tolerated, the patient will have longer turn abouts between the t-piece and the ventilator...and so on until the patient is fully weaned. They can go to the ward permamently on a t-piece. For turns, baths, transfers to radiology etc, we generally put the patient on a swedish nose for convenience, but then pop them back onto the t-piece as soon as practical.
We usually refer to them as Teebar on our unit. You can hook up a close suction setup to it, decreases risk for infection if they have frequent suction requirements. If they're just trying to wean off the vent and need humidification we do trach shield.