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Stethoscope: A Still-Relevant Tool and Medical Companion

      To the Editor:
      We read with interest the editorial by Frishman
      • Frishman W.H.
      Is the stethoscope becoming an outdated diagnostic tool?.
      entitled “Is the Stethoscope Becoming an Outdated Diagnostic Tool?” published in The American Journal of Medicine. The stethoscope and the semantics of auscultatory findings were invented more than 200 years ago by the French physician R.T. Laennec (Traité de l'Auscultation Médiate, Paris, 1819); over the years, very few changes have been made to either the stethoscope itself or the way in which it is used. More recently, we have seen advances in the techniques used to process auscultatory signals, as well as in the analysis and clarification of the resulting sounds.
      • Reichert S.
      • Gass R.
      • Kehayoff Y.
      • Brandt C.
      • Andrès E.
      Analysis of respiratory sounds: state of the art.
      The characterization of sounds through recording, analysis, and auscultatory signal-processing systems provides better sensitivity and specificity in several studies.
      • Andrès E.
      • Hajjam A.
      Advances and innovations in the field of auscultation.
      The availability of novel representations of the sounds, with phono- and spectrograms (Figure), not only opens interesting perspectives in the context of diagnostic aids, but also in education and pedagogy.
      • Andrès E.
      • Hajjam A.
      Advances and innovations in the field of auscultation.
      The recent developments of the new intelligent communicating system also offer new perspectives in the field of e-teaching.
      • Andrès E.
      • Hajjam A.
      Advances and innovations in the field of auscultation.
      Figure thumbnail gr1
      FigureRepresentation of a recording of a lung auscultation in a normal subject in the form of a phonopneumogram (top panel) and a spectrogram (lower panel) (data collected in the ASAP [Analyse des Sons Auscultatoires Pulmonaires, grant from the ANR Technologie 2006, France]; PRI [Perspectives et apports du développement d'un stéthoscope communiquant à l'ère de la télémédecine, grant from the University Hospital of Strasbourg, France] projects).
      A study conducted by our group with a population of medical students allowed us to quantify better diagnostic “performance” with new auscultatory signal-visualization tools in a setting of heart and lung disease assessment.
      • Andrès E.
      • Brandt C.
      • Mecili M.
      • Meyer N.
      Intérêt d'une démarche pédagogique structurée associée à de nouveaux outils de visualisation des signaux auscultatoires dans le cadre de l'apprentissage de la sémiologie auscultatoire: Étude prospective auprès de 30 étudiants du deuxième cycle des études médicales.
      We asked a cohort of medical graduate students (n = 30) to listen to 10 sounds in order to diagnose heart and lung pathology. Medical students (second cycle of the medical studies) first heard 10 sounds; they were then asked to check the appropriate box corresponding to the diagnosis relative to the sound they had just heard, as with an acoustic stethoscope (Day 0). The same exercise was conducted by adding the visual representation of the sound with phonopneumogram or phonocardiogram and spectrograms (Day 28). At Day 0, the correct response rate was 40% to 51%. In the second instance at Day 28, the rate of correct diagnosis reached 70% to 89%. Tables 1 and 2 present the details of these data. Analysis of these Tables shows that the improved performance (rate of correct diagnosis) is particularly significant for cardiac pathology. Thus, in our experience, addition of visual representation of sounds has significant implications in terms of medical education, and also in terms of decision-making, potential patient safety, and cost control.
      Table 1Global Results in Term of Good Diagnosis With the Use of New Tools as Phono- and Spectrogram for Visualizing Sounds in 30 Medical Students
      Day 0Day 28 Without ToolsDay 28 With ToolsComparison Between Day 0 and Day 28 With Tools
      “Good diagnosis”45% (136)64% (191)80% (239)P < .01
      “Good diagnosis” in respiratory auscultation51% (76)61% (92)70% (105)P = .058
      “Good diagnosis” in cardiac auscultation40% (60)66% (99)89% (134)P < .009
      Table 2Specific Results in Term of Lung or Cardiac Sounds Analysis With the Use of New Tools as Phono- and Spectrogram for Visualizing Sounds in 30 Medical Students
      All Students (n = 30)
      Without ToolsWith Tools
      % of “Good” diagnosis64% (191)80% (239)
      % of “Good” diagnosis in respiratory auscultation:61% (92)70% (105)
       Normal respiratory auscultation57% (17)63% (19)
       Crackles (chronic bronchitis)57% (17)60% (18)
       Crackles (interstitial pneumonia)53% (16)70% (21)
       Wheeze sibilants (acute crisis of asthma)70% (21)83% (25)
       Stridor (lung carcinoma)70% (21)73% (22)
      % of “Good” diagnosis in cardiac auscultation:66% (99)89% (134)
       Normal cardiac auscultation73% (22)93% (28)
       Aortic stenosis60% (18)100% (30)
       Aortic regurgitation (minimal murmur)30% (30)70% (21)
       Mitral stenosis40% (12)87% (26)
       Arrhythmia (auricular fibrillation)57% (17)97% (29)
      Conventional auscultation is subjective and not easily shared. Modern medical technology allows us to optimize auscultatory findings, and hence achieve a correct diagnosis by physically characterizing sounds through recordings, visualization, and automated analysis systems.
      • Reichert S.
      • Gass R.
      • Kehayoff Y.
      • Brandt C.
      • Andrès E.
      Analysis of respiratory sounds: state of the art.
      The development and availability of novel tools based on innovations in science and communications technology provide the clinician (as well as the students), with an invaluable aid in order to achieve an objective diagnosis, in addition to offering increased sensitivity and reproducibility of auscultatory findings. Such advances have led not only to the development and use of new intelligent communicating stethoscope systems, but they also have contributed significantly to the revival of telemedicine, particularly as a diagnostic and teaching aid; e-teaching, and pedagogy. Thus, in our opinion, the stethoscope is not becoming an outdated diagnostic tool.

      References

        • Frishman W.H.
        Is the stethoscope becoming an outdated diagnostic tool?.
        Am J Med. 2015; 128: 668-669
        • Reichert S.
        • Gass R.
        • Kehayoff Y.
        • Brandt C.
        • Andrès E.
        Analysis of respiratory sounds: state of the art.
        Clin Med Circ Respirat Pulm Med. 2008; 2: 45-58
        • Andrès E.
        • Hajjam A.
        Advances and innovations in the field of auscultation.
        Health Technol. 2012; 2: 5-16
        • Andrès E.
        • Brandt C.
        • Mecili M.
        • Meyer N.
        Intérêt d'une démarche pédagogique structurée associée à de nouveaux outils de visualisation des signaux auscultatoires dans le cadre de l'apprentissage de la sémiologie auscultatoire: Étude prospective auprès de 30 étudiants du deuxième cycle des études médicales.
        Pédagogie. 2012; 13: 39-50

      Linked Article

      • Is the Stethoscope Becoming an Outdated Diagnostic Tool?
        The American Journal of MedicineVol. 128Issue 7
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          During the past hundred years, the 3 major symbols representing the bedside physician have been the “black bag,” the white coat, and the stethoscope. It was a badge of honor during my second year of medical school to obtain all 3 items in anticipation of seeing patients on the hospital wards after the preclinical lecture hall experience. The stethoscope dangling from the pocket of the white coat or wrapped around the back of the neck meant to the outside world that you were now a member of the healing profession.
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