Neonatal high-frequency ventilation. Past, present, and future.

High-frequency ventilation has become established as an effective treatment modality in a variety of clinical situations. The laboratory and clinical investigations of these techniques have contributed tremendously to our understanding of the pathophysiology of respiratory failure and the important concept of maintaining adequate lung volume. Clinicians have come to appreciate better the factors involved in lung injury and the potential for damage to distant organs. The place of HFV in the therapeutic armamentarium will undoubtedly continue to evolve in the years to come. Of particular interest is the advent of advanced modes of fully synchronized and volume-targeted conventional mechanical ventilatory modes, along with the trend to use smaller tidal volumes and higher levels of PEEP with conventional ventilation. With these developments there seems to be a certain convergence of HFV and tidal ventilation that is the logical result of our improved understanding of respiratory pathophysiology. The available controlled trials of HFV versus tidal ventilation do not clearly differentiate whether improved outcomes are the result of HFV per se, or a reflection of the effects of optimizing lung volume, a benefit that may not be unique to HFV.