1.Design and application of a chest belt-type vibration expectorator.
Yan XU ; Chengcheng HE ; Wenzhe LI ; Dechang CHEN ; Siwen PAN
Chinese Critical Care Medicine 2025;37(5):490-493
Disruption of normal secretion or mucociliary clearance can impair airway defense mechanisms and lung function, and increase the risk of infection. Airway clearance techniques are recommended as part of a comprehensive treatment plan for patients. Among these, vibratory expectoration is an important method of airway clearance, which loosens and liquefies mucus and metabolites on the surface of the respiratory tract through chest wall oscillation, promoting ciliary movement to facilitate sputum expulsion. However, commonly used handheld vibrating head devices and vest-type vibration expectorators have several limitations in clinical practice, such as inconvenience of operation, limited treatment time, poor adaptability, and difficulty in disinfection. To address these issues, the research team from the department of critical care medicine at Ruijin Hospital, Shanghai Jiao Tong University, has designed a novel belt-type vibration expectorator, which has been granted a national utility model patent (Patent No.: ZL 2023 2 1610983.1). The device is mainly composed of a chest strap assembly, a sputum clearance component, and a fixed shoulder strap component. Several pockets are placed on the outer surface of the chest strap, with corresponding inner-side openings that allow the percussion head of the percussive expectorator placed inside the pocket to make contact with the patient's chest wall. Each pocket has markings indicating the percussion position, enabling the placement of the percussive expectorator according to the location of infection, thereby achieving multi-point, precise percussive vibration expectoration in different body positions. On the inner side of the chest strap, there are diagrams illustrating postural drainage, providing guidance on the body positions patients should assume based on the location of infection. The hook-and-loop fasteners on both sides of the chest strap can be wrapped around and secured according to the patient's body shape, ensuring that the sputum clearance components adhere tightly to the chest wall, allowing the vibrations generated by percussion to be effectively transmitted to the patient's airways. Additionally, to prevent the chest strap from slipping due to changes in the patient's position, a Y-shaped fixing strap can be selectively attached to the chest strap for further stabilization. This innovation not only simplifies the operation process, improves convenience and flexibility of use, but also supports the principle of "disinfection after each use by one person," which helps to reduce the risk of nosocomial infections and improve the efficiency of patients' respiratory rehabilitation.
Humans
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Vibration
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Equipment Design
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Chest Wall Oscillation/instrumentation*
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Sputum
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Expectorants
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Mucociliary Clearance
2.Application of wavelet analysis in pick-up of breath signal from oscillations in chest wall.
Journal of Biomedical Engineering 2012;29(1):65-69
In order to pick up breath signal from correlated noise background of the pulse of heart and artery etc, an algorithm based on wavelet de-noising has been introduced. With wavelet db4, the raw signal was decomposed into the scale space of six layers; threshold treatment was done with the self-adaptive threshold created by Stein's Unbiased Risk Estimate; then the wavelet coefficients were reconstructed. The result showed that the noise was significantly depressed.
Algorithms
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Artifacts
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Chest Wall Oscillation
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methods
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Humans
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Monitoring, Physiologic
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instrumentation
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methods
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Respiration
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Respiratory Sounds
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Signal Processing, Computer-Assisted
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Wavelet Analysis

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