 HFPV — High-frequency percussive ventilation combines HFV plus time cycled, pressure-limited controlled mechanical ventilation (i.e., pressure control ventilation, PCV).HFPPV — High-frequency positive pressure ventilation is rarely used anymore, having been replaced by high-frequency jet, oscillatory and percussive types of ventilation.HFPPV is delivered through the endotracheal tube using a conventional ventilator whose frequency is set near its upper limits.