Chronic Obstructive Pulmonary Disease (COPD)

Chronic obstructive pulmonary disease (COPD) is an umbrella term for a spectrum of chronic respiratory disorders characterized by symptoms including airflow limitation, impaired gas exchange, dyspnea and tissue inflammation. Functional and structural mucociliary impairment is characteristic; increased sputum production is common but not universal.

  1. Beck GJ. Chronic bronchial asthma and emphysema: Rehabilitation and use of thoracic vibrocompression. Geriatrics, 1966; 21: 139-158.

    In this earliest known clinical application of HFCC, the inventor/clinician described equipment consisting of an air pulse generator that delivered positive pressure of 30 cm H2O from a compressor passed over a vibrator operating at 30 Hz and applied to the upper abdomen and lower thorax with a thoracoabdominal belt. Outcomes include significant mucus expectoration, marked reduction of dyspnea and temporary or sustained benefit in severely obstructed patients.
  2. Chakravorty I, Chalal K, Austin G.  A pilot study of the impact of high-frequency chest wall oscillation in  chronic obstructive pulmonary disease patients with mucus hypersecretion. International J COPD 2011; 6: 693-699.
  3. George RJ, Winter RJ, Flockton SJ, Geddes DM. Ventilatory saving by external chest wall compression or oral high-frequency oscillation in normal subjects and those with chronic airflow obstruction. Clin Sci (Lond). 1985; 69:349-359.
Oscillation of the air within the lungs at high frequency is associated with an increased clearance of CO2. In this study, high-frequency oscillations were superimposed upon tidal breathing by using a loudspeaker attached to a mouthpiece to produce oral high-frequency oscillation (OHFO) or by external chest wall compression (ECWC). Changes in ventilation and breathlessness using OHFO and ECWC in normal subjects were compared with those in patients with chronic airflow obstruction (CAO). The pattern of breath conservation was then related to the resonant frequencies of the respiratory system as a whole (5-10 Hz in normal subjects, 16-26 Hz in CAO) and those of the ribcage (70 Hz). OHFO reduced minute ventilation (VE) by up to 46% in normal subjects (P = < 0.01) and 29% in CAO (P = < 0.01) without any rise in CO2. ECWC reduced VE by 27% in normal subjects (p = < 0.01) and 16% in CAO (p =< 0.01) without a rise in CO2. High-frequency oscillation by either method relieved breathlessness in those with CAO, was comfortable and well tolerated and may have value as a supplement to ventilation.
  4. Mahajan, AK, Diette GB, Hatipoglu U, et al.  High frequency chest wall oscillation for asthma and chronic obstructive pulmonary disease exacerbations: a randomized sham-controlled clinical trial. Resp Res 2011; 12:120.
    Reported high levels of patient adherence and satisfaction in both sham and standard HFCWO categories. Nearly twice as many patients treated with active HFCWO reported a clinically significant improvement in dyspnea than with sham HFCWO (71% vs. 42%). No significant differences were found in sputum, FEV1, length of stay, office visits.
  5. Perry RJ, Man GCW, Jones RL. Effects of positive-end expiratory pressure on oscillated flow rate during high-frequency chest compression. Chest 1998; 113 (4): 1028-1033.

    A comparative study of six normal subjects and six with stable COPD showed that, in the COPD group, the addition of a small amount of positive end expiratory pressure (PEEP) during HFCC therapy prevents decreased end-expiratory lung volume and increases mean oscillated flow rate during both phases of spontaneous breathing. The higher oscillated flow rates achieved during HFCC+PEEP may improve the effectiveness of HFCC in clearing mucus from the lungs of patients with airway disease.
  6. Piquet J, Brochard L, Isabey D, De Cremoux H, Chang HK, Bignon J, Harf A. High frequency chest wall oscillation in patients with chronic airflow obstruction. Am Rev Respir Dis 1987; 136:1355-1359.
    This study of 12 patients with severe COPD showed that high frequency chest wall oscillation (HFCWO) administered during expiration resulted in decreased respiratory rate, increased tidal volume, increased arterial PO2, decreased arterial PCO2, and decreased duty cycle (time of inspiration/total breath period). Results suggest that HFCWO may facilitate inspiratory muscle work and enhance both gas exchange and inspiratory muscle function. The potential of HFCWO to strengthen respiratory muscle function and improve ambulatory care in patients with severe COPD merits further investigation.
  7. Rumbak MJ, Marchione VL, Kennedy TC, Rolfe MW. Ninety-day assessment of the effect of high-frequency chest wall oscillation (HFCWO) on exercise tolerance and quality of life of patients with chronic obstructive pulmonary disease. Chest 2001; 120:4(Suppl): 250S. (Presented at ACCP Chest Conference, November 2001).
    In a 90-day trial of high frequency chest wall oscillation (HFCWO), COPD patients that completed the trial program and then elected to continue HFCWO therapy experienced statistically and/or clinically significant improvements in treatment and quality-of-life outcomes measured by validated instruments. Outcome domains include: 1) dyspnea; 2) six-minute walk distance; 3) quality of life (general health category); 4) treatment satisfaction and; 5) treatment adherence.

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