Influence of frequency and amplitude on the mucus viscoelasticity of the novel mechano-acoustic Frequencer™

Abstract

Background: Cystic fibrosis affects 1/3200 Caucasians. This genetic disease disturbs the ion and water homeostasis across epithelia, thus rendering mucus more viscous and harder to expel. Conventional treatments rely on the clapping method coupled with postural drainage. Despite the effectiveness of these procedures, they are invasive and enervating. Methods: Here we study a new mechano-acoustic treatment device to help patients expectorate excess mucus, the Frequencer™. We test both normal and pathological synthetic mucin solutions (1 % and 4 % by weight) in vitro. We varied the frequency applied (from 20 Hz to 60 Hz) as well as the amplitude (from 50 % to 100 % intensity). Moreover, we assessed the effect of NaCl on mucus rehydration. Results: A frequency of 40 Hz coupled with a 0.5 gL −1 NaCl solution provokes partial mucus rehydration, regardless of the amplitude selected, as the work of adhesion measurements evidenced. Conclusions: Mechanical solicitation is fundamental to help patients affected by cystic fibrosis expectorate mucus. With an operating frequency of 20 Hz to 65 Hz, the Frequencer™ provides a gentler therapy than traditional methods (conventional chest physiotherapy). The Frequencer™ proved to be effective in the homogenization of synthetic mucin solutions in vitro in 20 min and elicited improved effectiveness in a mucin-rich environment.

Vibroacoustic therapy in the treatment of patients with COVID-19 complicated by respiratory failure: a pilot randomized controlled trial

“…According to clinical observations, the frequency range from 20 to 60 Hz most effectively affects the chest. At the same time, the frequency range of vibroacoustic waves of 37–42 Hz for most patients is the most effective in terms of creating maximum pressure fluctuations in the lumen of the large airways ( 21 ). To enhance the effect in this frequency segment, a temporary emphasis is placed in all programs.…”

From Static to Dynamic: A Review on the Role of Mucus Heterogeneity in Particle and Microbial Transport

“…Up to date, research on McLs is based on in vivo , ex vivo , and in vitro models (Table ). − Regarding different organs, ,,− ages, ,, genders, , races, and health conditions, ,− mucus heterogeneity shows a tremendous significance. For in vivo models, mucus heterogeneity is exhibited among populations with regard to organs, age, gender, race, and health conditions.…”

On the effect of boundary vibration on mucus mobilization

“…In reality, wall vibration in human flow passages may be triggered through a mechanical solicitation (e.g., clapping of the chest walls) [74] or mechano-acoustic treatment devices (i.e. acoustic percussion) [29], to mention but a few.…”

“…It has been presented in numerous studies that the shear modulus of some of these fluids is frequency-dependent and increases to a plateau as the oscillation frequency increases [26][27][28]. Stress application rate and its continuity, triggered by acoustic waves, alter the non-linear stress-strain curve of non-Newtonian fluids and their elasticity, resulting in an improved displacement of these fluids [29]. The mathematical literature in this field can be categorized into either analytical or numerical approaches.…”