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

Frank V Ritacca,Thomas E Stewart

doi:10.1186/cc2182

Abstract

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.

Highlights

The development of the positive pressure mechanical ventilator in the 1950s marked a significant achievement in the care of patients with respiratory failure, and was a cornerstone in the establishment of the discipline of critical care medicine
We have learned that mechanical ventilation is often life saving, it can be injurious, especially in patients suffering from acute respiratory distress syndrome (ARDS) [1]
Mehta and colleagues studied 24 patients with severe ARDS failing conventional ventilation, and showed that High-frequency oscillatory ventilation (HFOV) could achieve an improvement in the PaO2/FiO2 ratio within 8 hours [31]

Summary

Introduction

The development of the positive pressure mechanical ventilator in the 1950s marked a significant achievement in the care of patients with respiratory failure, and was a cornerstone in the establishment of the discipline of critical care medicine. Mehta and colleagues studied 24 patients with severe ARDS (lung injury score = 3.4 ± 0.6 [41], pressure of arterial oxygen [PaO2]/FiO2 ratio = 98.8 ± 39.0) failing conventional ventilation (determined by ongoing hypoxemia or high plateau pressures), and showed that HFOV could achieve an improvement in the PaO2/FiO2 ratio within 8 hours [31]. The Multicenter Oscillatory Ventilation for Acute Respiratory Distress Syndrome Trial investigators randomized 150 patients with ARDS to HFOV (starting frequency = 5 Hz, Paw = 5 cmH2O greater than that on conventional ventilation) or to conventional ventilation using pressure control, with aims of achieving a Vt of 6–10 cm3/kg actual body weight [42]. These include the ideal timing of the intervention, the proper use of adjuncts like volume recruitment maneuvers, prone position, or nitric oxide, the ideal timing of discontinuation, the proper methods to manipulate the various indices such as Paw, ∆P, and frequency, and the effects on long-term outcomes such as lung function

Conclusion

Slutsky AS

Findings

17. The Acute Respiratory Distress Syndrome Network