Ventilator modes used in weaning.

Weaning techniques include spontaneous breathing trials (SBTs), pressure-support ventilation (PSV), and synchronized intermittent mandatory ventilation (SIMV). SBTs can be conducted using one of several approaches, including T-piece breathing, low-level continuous positive airway pressure, low-level PSV, or setting the ventilator to flow-triggering with no pressure applied to the airway. The SBT can be used as a method to identify extubation readiness or as a weaning technique in which the duration of the trial is gradually increased over time. With pressure-support weaning, the level of pressure support is gradually reduced over time. With weaning using SIMV, the mandatory rate setting on the ventilator is gradually reduced. Randomized controlled trials have reported the poorest weaning outcomes using SIMV. Although new ventilator modes have been introduced to facilitate weaning, to date there is no evidence to support the use of these modes. Noninvasive positive-pressure ventilation also has been reported to facilitate weaning, but the ability to generalize these findings remains to be determined.