An Acoustic Plethysmograph to Measure Total Infant Body Volume

Deskins, W.G.; Winter, D. C.; Sheng, Hwai-Ping; Garza, Cutberto

doi:10.1115/1.3138560

Cited by 5 publications

(2 citation statements)

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“…Therefore, by measuring the resonant frequency of the cavity, the volume of the cavity can be predicted. Deskins et al 2 used this theoretical approach to predict the behavior of an acoustic plethysmograph for measuring infant body volume. Rearranging the equation for the resonant frequency of a Helmholtz resonator and collecting the neck configuration terms into a constant, K, we obtain the following:…”

Section: Helmholtz Resonator Theorymentioning

confidence: 99%

Volume determination using acoustic resonance

Rothman

1989

The Journal of the Acoustical Society of America

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Cavities of irregular geometry can be modeled as Helmholtz resonators, provided they adhere to specific dimensional limits. If the characteristics of the entrance region or "neck" of a cavity are held fixed, the cavity's resonant frequency will be a function only of its volume. Using an electronic feedback technique and hand-held adapter, the Helmholtz resonator model has been applied to determine the volume of both simple and complex cavities, including castings of human nasal passages. Clinical application of this technique using live subjects is planned.

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Section: Helmholtz Resonator Theorymentioning

confidence: 99%

Volume determination using acoustic resonance

Rothman

1989

The Journal of the Acoustical Society of America

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“…In the first part of this research, the idea of using a resonating cavity to mea-sure changes in mouse volume was explored. The use of a resonating cavity to measure volume has been used in the past to design an infant plethysmograph for static body volume measurements [9,8,38]. By manually changing the frequency to measure the resonance of the plethysmograph with a subject inside, and comparing this to the resonance of an empty chamber, they were able to measure average body volume.…”

Section: Discussionmentioning

confidence: 99%

Acoustic plethysmograph for measuring pulmonary function in mice

Reynolds¹

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The traditional whole body plethysmograph (WBP) relies on pressure changes induced by a freely respiring animal inside a chamber. This pressure is a combination of a thermo-hygrometric effect (proportional to tidal volume) and a gas compression effect (related to lung mechanics). In order to measure either tidal volume or lung mechanics, it must be assumed that the other component is negligible. In this research, an acoustic WBP was developed that is capable of measuring the thoracic volume change of a mouse independent of the thermohygrometric effect. This allows independent measurement of tidal volume and specific airway resistance. I would like to express my gratitude to my wife, Elizabeth, and our children, Jacob, Katherine, Julia, and Caroline, who all put up with my grumpy moods during my many study sessions throughout this process. And most of all, I would like to thank my parents, Terry and Anita, who overcame their difficult upbringings to provide a family environment from which any achievement was possible. iv Contents Acknowledgments iv Table of Contents v List of Figures vii 1 Introduction 2 Background 2.1 Modeling physical systems with electric circuit analogues. .

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Unrestrained Acoustic Plethysmograph for Measuring Tidal Volume in Mice

Reynolds

Frazer

2006

Ann Biomed Eng

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The traditional method for measurement of tidal volume in unrestrained mice relies on pressure changes induced by a freely respiring animal in a whole body plethysmograph. These changes have been assumed to be the result of thermo-hygrometric differences between respired air and gas within the chamber. It is known, however, that gas compression in the lung can also contribute significantly to changes in plethysmograph pressure. This study describes an acoustic plethysmograph for mice that is capable of measuring the tidal volume time series without the errors associated with the traditional method. The plethysmograph was designed as a resonating cavity at a fixed frequency. It had a sharp resonant peak and was tuned so that changes in body volume produced nearly linear changes in sound amplitude. The plethysmograph was tested with a water filled balloon connected to a syringe pump. The volume of the balloon was varied as a triangle wave with an amplitude of 250 microL. The RMS error between measured and delivered volume was 4.43 microL. A volume step test, performed to assess the response time of the system, showed that the plethysmograph responded in less than one millisecond.

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An Acoustic Plethysmograph to Measure Total Infant Body Volume

Cited by 5 publications

References 0 publications

Volume determination using acoustic resonance

Volume determination using acoustic resonance

Acoustic plethysmograph for measuring pulmonary function in mice

Unrestrained Acoustic Plethysmograph for Measuring Tidal Volume in Mice

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