High-frequency ventilation.
High-frequency ventilation (HFV) provides respiratory gas exchange using positive airway pressure-driven tidal breaths that are often smaller than anatomic dead space and breathing frequencies several times faster than normal. Gas transport with HFV involves nonconvective mechanisms such as Taylor dispersion, coaxial flow, and augmented diffusion. Devices to deliver HFV include the jet (an airway injector delivers jet pulses) and the oscillator (a piston oscillates a bias flow of fresh gas). The conceptual advantage to HFV is that maximal airway pressures are limited by the small tidal breath and lung recruitment is optimized by the intrinsic positive end expiratory pressure effect. Outcome has been shown to be improved in pediatric patients at risk for volutrauma. Adult outcome data are still lacking.
MacIntyre
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Duke University Medical Center, Durham, North Carolina 27710, USA.