Comparison Between Breath Stacking and Air Stacking on Respiratory Mechanics and Ventilatory Pattern in Tracheostomized Patients: Randomized Crossover Trial

Breath stacking: patients were connected to a unidirectional valve coupled to artificial airway (tracheostomy), with bacteriological filter. The ventilator was coupled to the unidirectional valve to measure inspiratory volume mobilized in each cycle and a connection to adapt a manometer. The patient performed successive inspirations for a maximum period of 30 seconds or until unidirectional valve opening or volume increase was observed for 2 consecutive efforts. Ten cycles of the technique were performed, with an interval of 30 seconds.

Air stacking: the same system of monitoring and adaptation of the ventilometer and manometer was carried out. A manual resuscitator coupled to a unidirectional valve was used, both connected to the tracheostomy, with a filter interface. Slow and successive inspirations were performed through slow compression of the resuscitator until the maximum inspiratory pressure reached 40 cmH2O. Ten cycles of the technique were performed, with an interval of 30 seconds.