Introduction Lung auscultation is helpful in the diagnosis of lung and heart diseases; however, the diagnostic value of lung sounds may be questioned due to interobserver variation. This situation may also impair clinical research in this area to generate evidence-based knowledge about the role that chest auscultation has in a modern clinical setting. The recording and visual display of lung sounds is a method that is both repeatable and feasible to use in large samples, and the aim of this study was to evaluate interobserver agreement using this method.
Methods With a microphone in a stethoscope tube, we collected digital recordings of lung sounds from six sites on the chest surface in 20 subjects aged 40 years or older with and without lung and heart diseases. A total of 120 recordings and their spectrograms were independently classified by 28 observers from seven different countries. We employed absolute agreement and kappa coefficients to explore interobserver agreement in classifying crackles and wheezes within and between subgroups of four observers.
Results When evaluating agreement on crackles (inspiratory or expiratory) in each subgroup, observers agreed on between 65% and 87% of the cases. Conger’s kappa ranged from 0.20 to 0.58 and four out of seven groups reached a kappa of ≥0.49. In the classification of wheezes, we observed a probability of agreement between 69% and 99.6% and kappa values from 0.09 to 0.97. Four out of seven groups reached a kappa ≥0.62.
Conclusions The kappa values we observed in our study ranged widely but, when addressing its limitations, we find the method of recording and presenting lung sounds with spectrograms sufficient for both clinic and research. Standardisation of terminology across countries would improve international communication on lung auscultation findings.
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Contributors JCAS: analysis of data, data gathering, main responsibility for writing the manuscript. SV: design of the data analysis, analysis of data, substantial contributions to the final manuscript. PAH, EAA, NF, JWLC: data gathering, classification of sounds, substantial contributions to the final manuscript. AM, PP, HP: classification of sounds, substantial contributions to the final manuscript. HM: data collection, study design, substantial contributions to the final manuscript.
Funding General Practice Research Unit, Department of Community Medicine, UiT The Arctic University of Norway. The publication charges for this article have been funded by a grant from the publication fund of UiT The Arctic University of Norway.
Competing interests None declared.
Ethics approval The project was presented to the Regional Committee for Medical and Health Research Ethics, and it was considered to be outside the remit of the Act on Medical and Health Research.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data of the study is available.
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