Fig. 2From: Expiratory high-frequency percussive ventilation: a novel concept for improving gas exchangeExperimental protocol scheme. Measurements were initially made under normocapnic conditions (baseline) and continued during the maintenance of hypoxia and hypercapnia by decreasing the ventilation frequency. Four sequences including a high-frequency percussive ventilation (HFPV) and an expiratory high-frequency percussive ventilation (eHFPV), each preceded by a conventional mechanical ventilation (CMV), was then performed. Both HFPV and eHFPV were applied by randomly setting the oscillatory amplitude (2 or 4 cmH2O) and the oscillatory frequency (5 or 10 Hz). BG: blood gas; Vcap: volumetric capnography; Vent: recording the mechanical ventilation pressure/volume parameters; FOT: forced oscillationsBack to article page