High-frequency ventilation: a review.

As a new mode of assisted ventilation, high-frequency ventilation (HFV) embodies several types of devices, all of which employ tidal volumes much smaller and frequencies much greater than conventional mechanical ventilation (CMV). Due to the smaller swings of airway pressure during HFV, it is thought that some of the drawbacks of CMV may be overcome. Besides the obvious clinical implications, considerable interest has been generated concerning the physiological effects of HFV. In this review, the effects of HFV on gas exchange, lung mechanics, mucociliary transport, cardiovascular function and control of breathing will be examined. Although the role of HFV in the management of different lung diseases is still unclear, it has proved to be both a strong stimulus and a useful tool in the study of physiology.