The diagnostic value of pulmonary sounds: A preliminary study by computer-aided analysis

Urquhart, R.B.; McGhee, J.; Macleod, James E. S.; Banham, S. W.; Moran, F.

doi:10.1016/0010-4825(81)90002-0

Cited by 35 publications

(16 citation statements)

References 15 publications

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“…Forgacs [11] has claimed that the peak fre quency occurred at or near 200 Hz. Others showed peak frequencies at or near 160 Hz [12], 80 Hz [8], 25 Hz 113] and 5-50 Hz [14], The contour of the power spectrum is also not agreed upon. Gavriely et al [8] used a 75-Hz high-pass filter for all recorded lung sounds and found an exponential decline in power as a function of frequency up to 400 Hz.…”

Section: Discussionmentioning

confidence: 99%

“…Inspection of their data showed a considerable amount of sound energy below 75 Hz. Urquhart and associates [14] did not filter their recorded lung sounds, they found the power spectrum contours in their normal subjects more or less Gaus sian in nature with a peak frequency ranging from 5 to 50 Hz. Kraman [4] filtered his normal lung sound sig nals at 100-1,000 Hz with a half power point at 50 Hz, he found the frequency spectrum contours somewhat irregular with a Gaussian tendency and a frequency range of roughly 0-500 Hz.…”

Section: Discussionmentioning

confidence: 99%

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Reproducibility of the Vesicular Breath Sounds in Normal Subjects

1991

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Nonfiltered (NF) lung sounds from the apical area of the heart along with lung volumes and ECG signals were recorded from 5 normal subjects. The signals were digitized and subjected to three methods of heart sound cancelation: 75-Hz high-pass filtering (75 HF), ECG-triggered blanking (BL) and adaptive noise canceling (AF) [IEEE Trans. Biomed. Engng 33:1141–1148,1986]. The sound signals were then subjected to the fast Fourier transform algorithm to obtain power spectra. Five breaths from each subject were analyzed, and their spectra were similar and slightly skewed to the right. The average values of mean, median and mode frequencies of the whole breath of 5 subjects, respectively, were for NF: 64.62 ± 3.74, 44.57 ± 2.06 and 36.75 ± 1.79 Hz; for 75 HF: 150.42 ± 17.49, 114.02 ± 6.43 and 86.16 ± 3.13 Hz; for BL: 81.76 ± 6.02, 52.36 ± 2.79, 41.10 ± 3.15 Hz; for AF: 96.87 ± 11.58, 68.23 ± 10.44 and 52.25 ± 8.97 Hz. These values showed no differences between subjects. The F values obtained by the two-way analysis of variance of all breaths of all subjects (mean, median, mode) were: NF: 0.161, 0.341, 0.089; 75 HF: 0.455, 0.042, 0.085; BL: 0.108, 0.082, 0.057; AF: 0.130, 0.204, 0.113 (all p > 0.1). The data revealed a remarkable lack of variation within and between subjects, suggesting similar sites and mechanisms of production and transmission

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Reproducibility of the Vesicular Breath Sounds in Normal Subjects

1991

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“…By the mid-1970s, other types of microphone were being adopted; condenser and externally polarized microphones [6,12,[26][27][28][29][30], or electret microphones [23,[31][32][33][34]. A few research teams experimented with dynamic microphones [30], accelerometers, and various piezoelectric contact microphones [35][36][37][38], but the most suitable type was generally considered to be the condenser microphone [23].…”

Section: Sensorsmentioning

confidence: 99%

Acoustic properties of the normal chest

Dalmay

Antonini²,

Marquet³

et al. 1995

Eur Respir J

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Laënnec invented the stethoscope in 1816 and published a treatise on auscultation in 1819. We then had to wait until the 1950s to observe development of modern devices and methods of recording and signal-processing, which allowed objective studies of lung sounds in time and frequency fields.Tracheobronchial sounds generated by ventilation originate in the upper airways, the frequency content of these sounds has led to extensive research. Consolidated lungs act as more efficient sound conductors to the chest wall (bronchial breathing murmur). Tracheobronchial sounds contain higher frequency components compared to vesicular lung sounds.The origin of vesicular lung sounds has been becoming progressively clear for about 10 yrs. It is at least partly produced locally, deep, and probably intralobular. Clearly, further studies need to be performed in order to elucidate the true mechanisms involved in generating vesicular lung sounds, the redistribution of intrapulmonary gas or vibrations caused by the stretching of lung tissue.The devices developed are already useful for monitoring the state of patients in intensive care. Sooner or later, real time analysis and automated diagnosis will become available.

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“…There has been a controversy about the clinical significance of the low frequency sounds recorded, since some researchers have suggested that the low frequencies may also originate in the lungs [56,57]. The high-pass cut-off frequency has varied markedly in recent studies: no prefiltration [56,57], >50 Hz [48], >75 Hz [44], >100 Hz [13,58], >200 Hz [59], and >600 Hz [6,7].…”

Section: Recording and Analysis Of Crackling Soundsmentioning

confidence: 99%

Crackles: recording, analysis and clinical significance

Piirilä¹,

Sovijärvi²

1995

Eur Respir J

175

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Crackles are short interrupted breath sounds usually associated with pulmonary disorders. According to present opinion, a crackle is generated when an abnormally closed airway opens during inspiration or closes at the end of expiration. The timing of crackles in breathing cycles can be assessed with phonopneumography, their duration with time-expanded waveform analysis, and their pitch with analysis of frequency spectra. The timing, pitch and waveform of crackles are different in pulmonary disorders reflecting different pulmonary pathophysiology. This review deals with the genesis, auscultation, recording and analysis of crackles, with an emphasis on modern signal-processing methods.

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The diagnostic value of pulmonary sounds: A preliminary study by computer-aided analysis

Cited by 35 publications

References 15 publications

Reproducibility of the Vesicular Breath Sounds in Normal Subjects

Reproducibility of the Vesicular Breath Sounds in Normal Subjects

Acoustic properties of the normal chest

Crackles: recording, analysis and clinical significance

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