Visual Lung-Sound Characterization by Time-Expanded Wave-Form Analysis

Murphy, Raymond L. H.; Holford, Stephen K.; Knowler, William C.

doi:10.1056/nejm197704282961704

Cited by 173 publications

(95 citation statements)

References 7 publications

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“…Analysis of recordings from infants with classic wheeze indicated that the acoustic properties were very similar to those described in adults [10] whereas recordings from infants with ruttles confirmed the clinical impression that these are two distinctive respiratory sounds.…”

Section: Discussionmentioning

confidence: 62%

“…These position statements define wheezes as high-pitched musical sounds and bronchi as low-pitched continuous sounds. The waveform pattern for classical wheeze has been described previously by MURPHY et al [10] as "continuous undulating sinusoidal deflections" replacing the normal waveforms of lung sounds. The wheeze is continuous, which means a duration of >250 ms [14].…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

When a “wheeze” is not a wheeze: acoustic analysis of breath sounds in infants

Elphick¹,

Ritson²,

Rodgers³

et al. 2000

Eur Respir J

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Epidemiological studies indicate that the prevalence of "wheeze" is very high in early childhood. However, it is clear that parents and clinicians frequently use the term "wheeze" for a range of audible respiratory noises. The commonest audible sounds originating from the lower airways in infancy are ruttles, which differ from classical wheeze in that the sound is much lower in pitch, with a continuous rattling quality and lacking any musical features. The aim of this study was to clearly differentiate wheeze and ruttles objectively using acoustic analysis.Lung sounds were recorded in 15 infants, seven with wheeze and eight with ruttles, using a small sensitive piezoelectric accelerometer, and information relating to the respiratory cycle was obtained using inductive plethysmography. The acoustic signals were analysed using a fast fourier transformation technique (Respiratory Acoustics Laboratory Environment programme).The acoustic properties of the two noises were shown to be quite distinct, the classical wheeze being characterized by a sinusoidal waveform with one or more distinct peaks in the power spectrum display; the ruttle is represented by an irregular nonsinusoidal waveform with diffuse peaks in the power spectrum and with increased sound intensity at a frequency of <600 Hz.It is important for clinicians and epidemiologists to recognize that there are distinct types of audible respiratory noise in early life with characteristic acoustic properties.

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Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

When a “wheeze” is not a wheeze: acoustic analysis of breath sounds in infants

Elphick¹,

Ritson²,

Rodgers³

et al. 2000

Eur Respir J

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“…In 1969, FORGACS [1] subjectively coined the term "white noise" (energy being evenly distributed over a wide range of frequencies) to describe normal breathing sounds recorded close to the subject's mouth or at the trachea. This is confirmed by the chaotic waveform revealed when the amplitude of these sounds is recorded in extended time mode [57]. In 1981, GAVRIELY et al [36] calculated mean spectral frequencies (inspiration and expiration phases) showing that the log amplitude response curve remained virtually flat from 75 Hz (high-pass filter cut-off point) to about 900 Hz, before rapidly falling away at higher frequencies.…”

Section: Bronchial Soundsmentioning

confidence: 89%

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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“…Crackles were defined in accordance with accepted criteria. 11,12 This lung-sound analyzer has been validated as a crackle counter. 6 Crackle pitch was measured from the crackle waveform, as the inverse duration (in seconds) of one complete sinusoidal cycle.…”

Section: Methodsmentioning

confidence: 99%

Crackle Pitch and Rate Do Not Vary Significantly During a Single Automated-Auscultation Session in Patients With Pneumonia, Congestive Heart Failure, or Interstitial Pulmonary Fibrosis

2011

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OBJECTIVE:To determine the variability of crackle pitch and crackle rate during a single automated-auscultation session with a computerized 16-channel lung-sound analyzer. METHODS: Forty-nine patients with pneumonia, 52 with congestive heart failure (CHF), and 18 with interstitial pulmonary fibrosis (IPF) performed breathing maneuvers in the following sequence: normal breathing, deep breathing, cough several times; deep breathing, vital-capacity maneuver, and deep breathing. From the auscultation recordings we measured the crackle pitch and crackle rate. RESULTS: Crackle pitch variability, expressed as a percentage of the average crackle pitch, was small in all patients and in all maneuvers: pneumonia 11%, CHF 11%, pulmonary fibrosis 7%. Crackle rate variability was also small: pneumonia 31%, CHF 32%, IPF 24%. Compared to the first deepbreathing maneuver (100%), the average crackle pitch did not significantly change following coughing (pneumonia 100%, CHF 103%, IPF 100%), the vital-capacity maneuver (pneumonia 100%, CHF 92%, IPF 104%), or during quiet breathing (pneumonia 97%, CHF 100%, IPF 104%). Similarly, the average crackle rate did not change significantly following coughing (pneumonia 105%, CHF 110%, IPF 90%) or the vital-capacity maneuver (pneumonia 102%, CHF 101%, IPF 99%). However, during normal breathing the crackle rate was significantly lower in the patients with pneumonia (74%, P < .001) and significantly higher in the patients with IPF (147%, P < .05) than it was during deep breathing. In patients with CHF the average crackle rate during normal breathing was not significantly different from that during the first deep-breathing maneuver (108%). CONCLUSIONS: Crackle pitch and rate were surprisingly stable in all 3 conditions. Neither crackle pitch nor crackle rate changed significantly from breath to breath or from one deepbreathing maneuver to another, even when the maneuvers were separated by cough or the vitalcapacity maneuver. The observation that crackle rate is a reproducible measurement during one automated-auscultation session suggests that crackle rate can be used to follow the course of cardiopulmonary illnesses such as pneumonia, IPF, and CHF.

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Visual Lung-Sound Characterization by Time-Expanded Wave-Form Analysis

Cited by 173 publications

References 7 publications

When a “wheeze” is not a wheeze: acoustic analysis of breath sounds in infants

When a “wheeze” is not a wheeze: acoustic analysis of breath sounds in infants

Acoustic properties of the normal chest

Crackle Pitch and Rate Do Not Vary Significantly During a Single Automated-Auscultation Session in Patients With Pneumonia, Congestive Heart Failure, or Interstitial Pulmonary Fibrosis

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