July 2002 / Volume 47 / Number 7 / Page 797
High-Frequency Oscillation of the Airway and Chest Wall
IntroductionHigh-frequency oscillation (HFO), applied to either the airway or chest wall, has been associated with changes in sputum attributes and clearance. The evolution of evidence, both in vitro and in vivo, supporting the use of HFO is reviewed. Devices that apply HFO to the airway range from the relatively simple mechanical Flutter and Acapella devices to the more complex Percussionaire Intrapercussive Ventilators. The Vest and the Hayek Oscillator are designed to provide high-frequency chest wall compression. Operation and use of these devices are described with examples of differentiation of device types by characterization of flows, and airway and esophageal pressures. Although HFO devices span a broad range of costs, they provide a reasonable therapeutic option to support secretion clearance for patients with cystic fibrosis.
High Frequency Airway Oscillation Devices
Intermittent Percussive Ventilation (The Percussionator)
High-Frequency External Chest Wall Compression
The Hayek Oscillator
High-frequency oscillation (HFO) of the air column in the conducting airways represents one of several techniques available to facilitate secretion removal in vulnerable patients. A variety of devices are available that generate HFO by applying forces either at the airway opening or across the chest wall. These devices range from plastic hand-held products to table and floor models.
High-frequency oscillation was initially administered only to the cystic fibrosis (CF) population, but a growing body of peer-reviewed scientific literature and anecdotal case studies suggests the value of HFO for a wide range of pulmonary, neurologic, and neuromuscular disorders. This review explores the range of devices, their principles of operation, and the evidence supporting their use.