ABSTRACT
This chapter attempts to provide some intuitive insight into how and why high frequency ventilation (HFV) works. It presents an approach to understanding HFV, which hopefully will provide a framework in which to view the various mechanisms catalogued in the more complete published reviews. Further complicating the situation is the fact that different technical modes of deliverying HFV within a given species usually use different frequency ranges. Understanding how HFV works then becomes the task of understanding how alveolar and fresh gas are transported through the dead space at rates sufficient to provide the requisite gas exchange. To analyze quantitatively the amount of gas exchange and the ventilatory frequency required to maintain it, one needs to have an index of the nonsquareness of the gas front moving through the dead space. The chapter explains how ventilation with tidal volumes apparently insufficient to wash out completely the dead space can result in adequate gas exchange.
