Clinical review: high-frequency oscillatory ventilation in adults--a review of the literature and practical applications.

It has recently been shown that strategies aimed at preventing ventilator-induced lung injury, such as ventilating with low tidal volumes, can reduce mortality in patients with acute respiratory distress syndrome (ARDS). High-frequency oscillatory ventilation (HFOV) seems ideally suited as a lung-protective strategy for these patients. HFOV provides both active inspiration and expiration at frequencies generally between 3 and 10 Hz in adults. The amount of gas that enters and exits the lung with each oscillation is frequently below the anatomic dead space. Despite this, gas exchange occurs and potential adverse effects of conventional ventilation, such as overdistension and the repetitive opening and closing of collapsed lung units, are arguably mitigated. Although many investigators have studied the merits of HFOV in neonates and in pediatric populations, evidence for its use in adults with ARDS is limited. A recent multicenter, randomized, controlled trial has shown that HFOV, when used early in ARDS, is at least equivalent to conventional ventilation and may have beneficial effects on mortality. The present article reviews the principles and practical aspects of HFOV, and the current evidence for its application in adults with ARDS.