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Discovering new facts and revealing existing myths about the acoustic stethoscope 200 Discovering new facts and revealing existing myths about the acoustic stethoscope 200

Discovering new facts and revealing existing myths about the acoustic stethoscope 200 - PowerPoint Presentation

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Discovering new facts and revealing existing myths about the acoustic stethoscope 200 - PPT Presentation

Lukasz Nowak a Karolina Nowak b a Institute of Fundamental Technological Research Polish Academy of Sciences Poland b Centre of Postgraduate Medical Education Poland ID: 784586

acoustic stethoscope medical auscultation stethoscope acoustic auscultation medical diaphragm phenomena stethoscopes chestpiece research myths facts physician binaural bell acoustics

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Slide1

Discovering new facts and revealing existing myths about the acoustic stethoscope 200 years after its invention

Lukasz Nowak(a), Karolina Nowak(b)

(a) Institute of Fundamental Technological Research,

Polish

Academy

of

Sciences

,

Poland

(b) Centre of Postgraduate Medical Education,

Poland

Slide2

Research project: „New Methods and Technologies for Acoustic Medical Diagnotics”Aim of the project: to develop a new generation of methods and technologies for acoustic medical diagnosticsMultidisciplinary team of scientists and physicians combining clinical knowledge and strong background in acoustics, electronics and signal processing2Introduction

Slide3

Theoretical and experimental investigations on the physical phenomena underlying the auscultation examinationsState of the art revisionAuscultation signals database: heart, breath, and other soundsSignal analysis and processing: algorithms and softwareElectronic stethoscopes: development, construction, measurements3What do we do?

Slide4

Invented 200. years ago, in 1816, by French physician, Rene LaennecThe first non-lethal instrument for exploring internal anatomy1850s: binaural stethoscopeThe symbol of healthcare professionalsThe most widespread and commonly used medical diagnostic device4Stethoscope - facts

Slide5

David Littmann, An approach to the ideal stethoscope, Journal of the American Medical Association, Vol 178 (5), 1961, pp :504-505.basic assumptions concerning the construction and theory of operation of the modern acoustic stethoscopes – „desireable features”5Modern acoustic stethoscopesTwo chest

pieces (bell and diaphragm), tubing, binaural and earpieces

Single-

chestpiece

stethoscopes

with „

tunable

diaphragm

Slide6

Just a few silmple components…6Stethoscope – mythsSimplest diagnostic device you can imagine?chestpiecetubing

binauralearpieces

Slide7

Patient -> stethoscope -> Physician: coupled acoustic system7Stethoscope – factsUnderlying phenomena still not really well understood…chestpiece

tubingbinauralearpiecesPATIENTPHYSICIAN

Slide8

8Auscultation soundsreal world vs. ideal world

Slide9

BELL:„amplifying low-pitched sounds”skin as a diaphragmheart auscultation„lower natural resonances” [large chestpiece]DIAPHRAGM:„attenuating low-pitched sounds”stiff diaphragmlung auscultation9Bell vs. diaphragm

facts or myths?

Slide10

10Bell vs. diaphragmexperimental methodologyErtel P. Y., Lawrence M., Brown R. K. and Stern A. M. Stethoscope Acoustics II.Transmission and Filtration Patterns, Circulation, Vol 34 (5), 1966, pp 899-909.Welsby P. D., Parry G. and Smith D. The stethoscope: some preliminary investigations, Postgraduate Medical Journal, Vol 79 (938), 2003, pp 695-698.

Slide11

11Bell vs. diaphragmmeasurements and results

Lung auscultation sounds spectra

Slide12

Heart auscultation sounds spectra12Bell vs. diaphragmmeasurements and results cont’d

Slide13

13Tunable diaphragmsfacts or myths?

Slide14

14Hollow tubesfacts & measurements

Slide15

Stethoscope is a simple acoustic device, but mechanisms and phenomena underlying auscultation are very complex and not yet properly understoodMany common theses concerning stethoscope have no proper scientific justification……and some of them seem to be just wrongMuch of a scientific effort in the field is devoted to Computer Aided Auscultation

systems……but can it really repleace the physician on the other side of the stethoscope?15Summaryfuture of auscultation?

Slide16

16Thank you for your attentionemail: lnowak@ippt.pan.pl

The authors would like to acknowledge the financial support from the Polish National Centre for Research and Development (NCBiR), grant no.LIDER/034/037/L-5/13/NCBR/2014