title: Inspiratory high frequency airway oscillation attenuates resistive loaded dyspnea and modulates respiratory function in young healthy individuals.
abstract: Direct chest-wall percussion can reduce breathlessness in Chronic Obstructive Pulmonary Disease and respiratory function may be improved, in health and disease, by respiratory muscle training (RMT). We tested whether high-frequency airway oscillation (HFAO), a novel form of airflow oscillation generation can modulate induced dyspnoea and respiratory strength and/or patterns following 5 weeks of HFAO training (n = 20) compared to a SHAM-RMT (conventional flow-resistive RMT) device (n = 15) in healthy volunteers (13 males; aged 20-36 yrs). HFAO causes oscillations with peak-to-peak amplitude of 1 cm H2O, whereas the SHAM-RMT device was identical but created no pressure oscillation. Respiratory function, dyspnoea and ventilation during 3 minutes of spontaneous resting ventilation, 1 minute of maximal voluntary hyperventilation and 1 minute breathing against a moderate inspiratory resistance, were compared PRE and POST 5-weeks of training (2 × 30 breaths at 70% peak flow, 5 days a week). Training significantly reduced NRS dyspnoea scores during resistive loaded ventilation, both in the HFAO (p = 0.003) and SHAM-RMT (p = 0.005) groups. Maximum inspiratory static pressure (cm H2O) was significantly increased by HFAO training (vs. PRE; p<0.001). Maximum inspiratory dynamic pressure was increased by training in both the HFAO (vs. PRE; p<0.001) and SHAM-RMT (vs. PRE; p = 0.021) groups. Peak inspiratory flow rate (L.s(-1)) achieved during the maximum inspiratory dynamic pressure manoeuvre increased significantly POST (vs. PRE; p = 0.001) in the HFAO group only. HFAO reduced inspiratory resistive loading-induced dyspnoea and augments static and dynamic maximal respiratory manoeuvre performance in excess of flow-resistive IMT (SHAM-RMT) in healthy individuals without the respiratory discomfort associated with RMT.
authors.affiliation: Centre of Human & Aerospace Physiological Sciences, King's College London, London, United Kingdom.
authors.forename: Theresa
authors.initials: T
authors.lastname: Morris
authors.affiliation: Applied Science, Engineering, Science and the Built Environment, London South Bank University, London, United Kingdom.
authors.forename: David Paul
authors.initials: DP
authors.lastname: Sumners
authors.affiliation: Centre of Human & Aerospace Physiological Sciences, King's College London, London, United Kingdom.
authors.forename: David Andrew
authors.initials: DA
authors.lastname: Green
mesh_terms: D000328:Adult; D001945:Breathing Exercises; D004417:Dyspnea / Q000503:physiopathology*; D005260:Female; D006262:Health; D006612:High-Frequency Ventilation; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology; D001239:Inhalation / Q000502:physiology*; D008176:Lung Volume Measurements; D008297:Male; D012132:Respiratory Muscles / Q000503:physiopathology; D012146:Rest; D055815:Young Adult