Enhanced Tracheal Mucus Clearance with High Frequency Chest Wall Compression

TLDR

In nine anesthetized dogs, high‑frequency chest wall compression was applied by oscillating a thoracic cuff to generate tidal volumes of 25–100 cc at 3–17 Hz, and tracheal mucus clearance was quantified by tracking charcoal particle displacement with a fiberoptic bronchoscope. HFCWC increased tracheal mucus clearance by up to 340 % of baseline, with maximal effect at 13 Hz, indicating a promising physiotherapy modality.

Abstract

The clearance of mucus in the trachea during high frequency chest wall compression (HFCWC) was studied in nine anesthetized dogs. High frequency chest wall compression was applied by oscillating the pressure in a thoracic cuff such that it produced oscillatory tidal volumes of 25 to 100 cc at frequencies of 3 to 17 Hz. The tracheal mucus clearance rate (TMCR) was determined by direct observation of the rate of displacement of a charcoal particle spot by means of a fiberoptic bronchoscope. Baseline TMCR during spontaneous breathing averaged 8.2 ± 5.6 mm/min in the 9 dogs. The TMCR during 2 min of HFCWC was increased at 5, 8, 11, 13, 15, and 17 Hz but not at 3 Hz. The enhancement of clearance was most pronounced in the range of 11 to 15 Hz, reaching a peak value of 340% of control at 13 Hz. These studies suggest that HFCWC might be of considerable potential benefit as a mode of chest physiotherapy.