HFCC- Mechanisms of Action
Laboratory and clinical studies of high frequency chest compression (HFCC) technology have elucidated both mechanisms of action and physiological effects. The majority of these studies have been published in the peer-reviewed literature.
In the 1960s, 70s and 80s, high-frequency chest compression (HFCC) technology was investigated extensively in the laboratory and in limited clinical situations. A variety of in-vitro, animal and human subjects studies have elucidated and confirmed several mechanisms of action and physiological effects. Since 1988, a series of progressively improved HFCC devices were created to augment mucociliary clearance in the clinical setting. Among these, the inCourage™ system incorporates the most recent advances in HFCC science. When HFCC therapy with the inCourage™ system is activated, rapid compressions of the chest wall produce oscillations within the airways, inducing passive staccato cough-like effects. As a result, much greater volumes of air are expelled from the lungs than during forced expiration. Basic HFCC studies demonstrate the following mechanical/physiological effects:
Mucus adherent to bronchial walls is loosened
The greater the velocity of HFCC - induced airflow, the greater the strength of shear forces that act to dislodge accumulated mucus from airway passages
Thick secretions are physically altered, thus enhancing clearability
HFCC - induced interruption of glycoprotein bonds favorably alters mucus rheology to enhance mucus-mobilizing ciliary activity
An airflow bias mobilizes particle-laden secretions toward central airways for elimination by coughing or expectoration
Radioactive tracers attached to carbon particles demonstrate cephalad movement of mucus from smaller to larger airways
HFCC significantly accelerates tracheal mucus velocity (TMV), thus increasing clearance rates and reducing prolonged exposure of the lung to stagnant, purulent secretions
Measurements of tracheal mucus clearance rates (TMCR) show that HFCC increases mucus mobilization up to 340% of that achieved during spontaneous breathing in healthy subjects
HFCC correlates with improved ventilation in both animal and clinical studies
The FDA has approved high frequency chest compression (HFCC) to promote airway secretion clearance; currently, the device is marketed solely for that purpose. However, encouraging data from several research studies demonstrate that HFCC also improves ventilation in the lungs. Although such effects may be clinically beneficial, this aspect of the therapy has not been fully evaluated. Further study is merited.
See also…
Research and Evidence
Clinical Trials
Research Studies
Annotated Bibliography
Articles
