We studied the mechanisms by which turbulent flow induces tracheal wall vibrations detected as tracheal breath sounds (TRBSs). The effects of flow rate at transitional Reynold's numbers (1300–10,000) and gas density on spectral patterns of TRBSs in eight normal subjects were measured. TRBSs were recorded with a contact sensor during air and heliox breathing at four flow rates (1.0, 1.5, 2.0, and 2.5 l/s). We found that normalized TRBSs were proportional to flow to the 1.89 power during inspiration and to the 1.59 power during expiration irrespective of gas density. The amplitude of TRBSs with heliox was lower than with air by a factor of 0.33 ± 0.12 and 0.44 ± 0.16 during inspiration and expiration, respectively. The spectral resonance frequencies were higher during heliox than air breathing by a factor of 1.75 ± 0.2—approximately the square root of the reciprocal of the air/heliox wave propagation speed ratio. In conclusion, the flow-induced pressure fluctuations inside the trachea, which cause tracheal wall vibrations, were detected as TRBSs consist of two components: (1) a dominant local turbulent eddy component whose amplitude is proportional to the gas density and nonlinearly related to the flow; and (2) a propagating acoustic component with resonances whose frequencies correspond to the length of the upper airway and to the free-field sound speed. Therefore, TRBSs consist primarily of direct turbulent eddy pressure fluctuations that are perceived as sound during auscultation.
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Similar content being viewed by others Explore related subjectsDiscover the latest articles and news from researchers in related subjects, suggested using machine learning. ReferencesAgarwal, N. K. The sound field in fully developed turbulent flow separation, Part 1: Wall-pressure fluctuations. J. Sound Vib. 169:89–109, 1994.
Agarwal, N. K. The sound field in fully developed turbulent flow separation, Part 2: Wall-modal amplitude and cut-off frequencies. J. Sound Vib. 175:65–76, 1994.
Agarwal, N. K., and M. K. Bull. Acoustic wave propagation in a pipe with fully developed turbulent flow. J. Sound Vib. 132:275–298, 1989.
Altmann, P. L., and D. S. Dittmer. Biological Handbooks, Respiration and Circulation. Bethesda, MD: Federation of American Societies for Experimental Biology, 1971, Table 49, pp. 105–108.
Bull, M. K., and M. P. Norton. On the hydrodynamic and acoustic wall pressure fluctuations in turbulent pipe flow due to a 90° mitred bend. J. Sound Vib. 76:561–586, 1981.
Coleman, R. F., and G. L. Schechter. A basic model to study acoustic evaluation of airway obstruction. Arch. Otolaringol. Head Neck Surg. 117:1144–1149, 1991.
Gavriely, N., Y. Palti, and G. Alroy. Spectral characteristics of normal breath sounds. J. Appl. Physiol. 50:307–314, 1981.
Gavriely, N. Breath Sounds Methodology. Boca Raton, FL: CRC Press, 1995, pp. 31–33.
Gavriely, N., and D. W. Cugell. Airflow effects on amplitude and spectral content of normal breath sounds. J. Appl. Physiol. 80:5–13, 1995.
Griscom, N. T., and M. E. B. Wohl. Dimensions of the growing trachea related to body height. Length, anteroposterior and transverse diameters, cross-sectional area and volume in subjects younger than 20 years of age. Am. Rev. Respir. Dis. 131:840–844, 1985.
Harper, P., S. S. Kraman, H. Pasterkamp, and G. R. Wodicka. An acoustic model of the respiratory tract. IEEE Trans. Biomed. Eng. 48:543–550, 2001.
Harper, V. P., H. Pasterkamp, H. Kiyokawa, and G. R. Wodicka. Modeling and measurement of flow effect on tracheal sounds. IEEE Trans. Biomed. Eng. 50:1–10, 2003.
Lessard, C. S., and W. C. Wong. Correlation of constant flow rate with frequency spectrum of respiratory sounds when measured at the trachea. IEEE Trans. Biomed. Eng. 33:461–463, 1986.
Meyer, E., and E. G. Neumann. Physical and Applied Acoustics. New York: Academic Press, 1972, pp. 384–403.
Morse, P. M., and K. U. Ingard. Theoretical Acoustics. New York: McGraw-Hill Book Company, 1968, pp. 768–777.
Olson, D. E., M. Bogyi, D. B. Schwartz, and J. R. Hammersley. Relationship of tracheal breath sounds to airflow. Am. Rev. Respir. Dis. 129:A256, 1984 (abstract).
Pasterkamp, H., I. Sanchez, and Y. Oh. Effect of gas density and breathing apparatus on tracheal sounds. Am. Rev. Respir. Dis. 144:A456, 1991.
Rayleigh, L. Theory of Sound. 1984, Vol. II, pp. 376–414.
Regier, A. A., H. H. Hubbard, and L. W. Lassiter. Jet noise. In: Technical Aspects of Sound, edited by E. G. Richardson. Amsterdam: Elsevier Publishing Company, 1957, Vol. II, pp. 357–383.
Richardson, E. G. Flow noise. In: Technical Aspects of Sound, edited by E. G. Richardson and E. Meyer. New York: Elsevier Publishing Company, 1962, Vol. III, pp. 123–177.
Sanchez, I., and H. Pasterkamp. Tracheal sound spectra depend on body height. Am. Rev. Respir. Dis. 148:1083–1087, 1993.
Schlichting, H. Boundary-layer Theory. New York: McGraw-Hill Book Company, 1979, 7th ed.
White, F. M. Fluid Mechanics. New York: McGraw-Hill Book Company, 1994, 3rd ed., p. 314.
Department of Physiology and Biophysics, Bruce Rappaport Faculty of Medicine and the Rappaport Institute, Technion, Haifa, 31096, Israel
Raphael Beck, Muhammad Mahagnah & Noam Gavriely
Faculty of Civil Engineering, Technion, Haifa, 32000, Israel
Giora Rosenhouse
Department of Anesthesia, Northwestern University Medical School, Chicago, IL, 60611
Raymond M. Chow
Pulmonary Division, Department of Medicine, Northwestern University Medical School, Chicago, IL, 60611
David W. Cugell
Faculty of Medicine, Technion–IIT, P.O. Box 9697, Haifa, 31096, Israel
Noam Gavriely
Correspondence to Noam Gavriely.
About this article Cite this articleBeck, R., Rosenhouse, G., Mahagnah, M. et al. Measurements and Theory of Normal Tracheal Breath Sounds. Ann Biomed Eng 33, 1344–1351 (2005). https://doi.org/10.1007/s10439-005-5564-7
Received: 09 March 2003
Accepted: 27 April 2005
Issue Date: October 2005
DOI: https://doi.org/10.1007/s10439-005-5564-7
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