Enhanced Tracheal Mucus Clearance with High Frequency Chest Wall Compression

King, M.; Phillips, D M; Gross, D; Vartian, V.; Chang, H K; Zidulka, A.

doi:10.1164/arrd.1983.128.3.511

Cited by 160 publications

(107 citation statements)

References 16 publications

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“…horizontal) to maximise the oscillation amplitude and to target the mid-frequency range of oscillation of 10-15 Hz [12]. This mid-frequency range is proposed to have maximal effect on mucus transport [4,13]. The Acapella1 was used according to manufacturer's recommendations (DHD Healthcare) with the resistance set by adjusting the numerical dial to the minimal level at which each subject could exhale for 3-4 s while feeling the vibratory effects.…”

Section: Methodsmentioning

confidence: 99%

“…These include: 1) increasing absolute peak expiratory flow rates (PEFR) to move secretions towards the oropharynx [2]; 2) improving the expiratory bias of airflow to increase the annular flow of mucus towards the oropharynx, which occurs when the PEFR is 10% greater than peak inspiratory flow rate (PIFR), i.e. PEFR/PIFR ratio .1.1 [3]; 3) increasing mucus transport by decreasing the viscosity of mucus and improving expiratory flow due to the effects of oscillation of airflow at frequencies ranging from 3-17 Hz [4]; and 4) eliciting spontaneous coughs via the mechanical stimulation of the airways [5].…”

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confidence: 99%

“…Secretion clearance may be aided by the oscillation of airflow [4]. All the physiotherapy interventions, with the exception of PEP, had an oscillation frequency within the 3-17 Hz range shown to facilitate mucociliary clearance [4].…”

mentioning

confidence: 99%

“…All the physiotherapy interventions, with the exception of PEP, had an oscillation frequency within the 3-17 Hz range shown to facilitate mucociliary clearance [4]. These oscillation frequencies may assist secretion clearance by altering rheology of the mucus [4] and increasing ciliary beat through stimulation of the ciliated epithelial cells [24,25]. The oscillation frequencies of Flutter1 (11.3 Hz) and Acapella1 (13.5 Hz) were close to the cited optimal frequency for secretion clearance (13 Hz) [4,13].…”

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confidence: 99%

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Physiological effects of vibration in subjects with cystic fibrosis

McCarren

Alison²

2006

Eur Respir J

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The physiological mechanisms by which vibration and other physiotherapy interventions may clear secretions in subjects with cystic fibrosis are unknown. The main aim of this study was to compare the expiratory flow rates and frequencies of airflow oscillation of vibration to those of Acapella1, Flutter1, positive expiratory pressure and percussion.Respiratory flow rates were measured during interventions, the order of which was randomised. The oscillation of the airflow of the interventions was determined by frequency spectral analysis.In 18 young adult subjects with cystic fibrosis, the mean peak expiratory flow rate of vibration was greater than Flutter1, percussion, Acapella1 and positive expiratory pressure. The mean¡SD of the oscillation of the airflow of vibration (8.4¡0.4 Hz) was lower than Acapella1 (13.5¡1.7 Hz) and Flutter1 (11.3¡1.5 Hz) but similar to percussion (7.3¡0.3 Hz).Theoretically, the higher peak expiratory flow rate of vibration compared to the other physiotherapy interventions may promote secretion clearance. In addition, the frequency of oscillation of vibration was within the range demonstrated to increase mucus transport. This study has provided some evidence for the physiological rationale for the use of vibration to aid secretion clearance.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Physiological effects of vibration in subjects with cystic fibrosis

McCarren

Alison²

2006

Eur Respir J

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“…the "linear" velocity of mucociliary clearance, can be determined by direct observation of marker particle movement with the aid of a fibreoptic bronchoscope [16]. Mainstem bronchial mucus velocities can also be measured under bronchoscopic control; these are useful in monitoring the effects of local or unilateral interventions.…”

Section: Mucus and Mucociliary Clearancementioning

confidence: 99%

Experimental models for studying mucociliary clearance

King¹

1998

Eur Respir J

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Respiratory tract mucus is a viscoelastic gel, the rheological properties of which are determined mainly by its content of mucous glycoproteins and water. The rheology and quantity of mucus, in concert with ciliary factors, are the major determinants of mucociliary clearance.A wide range of animal models for studying the secretion and clearance of mucus are available. Ex vivo models, such as the frog palate or excised bovine trachea, provide direct, meaningful data regarding the clearability of mucus. Rodent models of chronic bronchitis, based on irritant gas or cigarette smoke exposure, show important features of the human condition in a relatively short time. The rheological characterization of mucus is made difficult by the small quantities obtainable, particularly from normal animals.Large animal models, such as the dog or sheep, although more expensive, offer many advantages, such as the ability to carry out long-term serial measurements, and to make integrated measurements of the clearance of mucus, ciliary function, epithelial ion transport, and the rheology of mucus in the same preparation. Eur Respir J 1998; 11: 222-228 The viscoelastic properties of mucusDue to the cross-linking of glycoproteins, the rheological behaviour of mucus is described as viscoelastic, having characteristics of both a liquid and a solid [1,2]. Viscosity is the resistance to flow, and represents the capacity of a material to absorb energy as it moves. Elasticity is the capacity of a material to store the energy used to move or deform it. With ideal fluids, viscosity is independent of the stress applied. With viscoelastic liquids, such as mucus, viscosity decreases with increasing stress or rate of strain (shear rate). Mucus responds to stress with an initial solid-like deformation, followed by a viscoelastic deformation and finally by a period of steady flow, in which the rate of deformation is constant. Only partial recovery of the strain follows removal of the stress, indicating a permanent deformation of its gel structure. Changes in the viscosity and elasticity of mucus are generally interrelated.Mucus exhibits shear-thinning following exposure to high shear forces, exhibiting a decreased viscosity at low shear rates. Some shear-thinning may be permanent, indicating altered molecular structure, whilst some shearthinning, termed "thixotropy", may be reversible.The viscoelasticity of mucus can be effectively described by two relatively independent quantities, G* and tangent (tan) δ, which vary with measurement frequency. The mechanical impedance (G*), is the vector sum of viscosity and elasticity; it can be termed the "rigidity factor". Tan δ is the ratio of viscosity to elasticity; it is also known as the loss tangent and can be considered as a "recoil factor". The relative proportions of elasticity and viscosity are important in describing how a material, such as mucus, behaves when it is subjected to external forces. Rheological assessment of mucus Collection of mucusTracheal mucus can be collected by a modificat...

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