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

Vyshedskiy, Andrey; Ishikawa, Sadamu; Murphy, Raymond L. H.

doi:10.4187/respcare.00999

Cited by 14 publications

(11 citation statements)

References 23 publications

(26 reference statements)

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“…This has also been observed in subjects with interstitial pulmonary fibrosis when comparing crackle rate during normal and deep-breathing maneuvers. 37 This may be related to the effect of lung expansion, as recordings were repeated at short intervals. 38 During the first breathing maneuvers, regions of deflated airways probably opened, and in the following maneuvers, the production of crackles decreased.…”

Section: Discussionmentioning

confidence: 99%

Computerized Respiratory Sounds Are a Reliable Marker in Subjects With COPD

Jácome

Marques²

2015

Respir Care

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BACKGROUND: Computerized respiratory sounds have shown potential in monitoring respiratory status in patients with COPD. However, the variability and reliability of this promising marker in COPD are unknown. Therefore, this study assessed the variability and reliability of respiratory sounds at distinct air flows and standardized anatomic locations in subjects with COPD. METHODS: A 2-part study was conducted. Part 1 assessed the intra-subject reliability of respiratory sounds at spontaneous and target (0.4 -0.6 and 0.7-1 L/s) air flows in 13 out-patients (69.3 ؎ 8.6 y old, FEV 1 of 70.9 ؎ 21.4% of predicted). Part 2 characterized the inter-subject variability and intra-subject reliability of respiratory sounds at each standardized anatomic location, using the most reliable air flow, in a sample of 63 out-patients (67.3 ؎ 10.4 y old, FEV 1 of 75.4 ؎ 22.9% of predicted). Respiratory sounds were recorded simultaneously at 7 anatomic locations (trachea and right and left anterior, lateral, and posterior chest). Air flow was recorded with a pneumotachograph. Normal respiratory sound intensity and mean number of crackles and wheezes were analyzed with validated algorithms. Inter-subject variability was assessed with the coefficient of variation, and intra-subject reliability was assessed with the intraclass correlation coefficient (ICC) and Bland-Altman plots. RESULTS: Relative reliability was moderate to excellent for normal respiratory sound intensity and mean number of crackles (ICC of 0.66 -0.89) and excellent for mean number of wheezes (ICC of 0.75-0.99) at the 3 air flows. Absolute reliability was greater at target air flows, especially at 0.4 -0.6 L/s. Inter-subject variability was high for all respiratory sound parameters and across locations (coefficient of variation of 0.12-2.22). Respiratory sound parameters had acceptable relative and absolute intra-subject reliability at the different anatomic locations. The only exception was the mean number of crackles at the trachea, for which both relative and absolute reliability were poor. CONCLUSIONS: Respiratory sound parameters are more reliable at an air flow of 0.4 -0.6 L/s and are reliable overall at all anatomic locations. This should be considered in future studies using computerized auscultation.

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Section: Discussionmentioning

confidence: 99%

Computerized Respiratory Sounds Are a Reliable Marker in Subjects With COPD

Jácome

Marques²

2015

Respir Care

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“…This method provides an estimate of gas flow. At the flow rates we used in this study, tracheal gas flow is proportional to the root mean square of the sound amplitude: doubling the gas flow results approximately in doubling the root mean square of the sound amplitude [4, 8–14]. …”

Section: Methodsmentioning

confidence: 99%

Pendelluft in Chronic Obstructive Lung Disease Measured with Lung Sounds

Vyshedskiy

Murphy

2012

Pulmonary Medicine

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Objective. The phenomenon of pendelluft was described over five decades ago. In patients with regional variations in resistance and elastance, gas moves at the beginning of inspiration out of some alveoli into others. Gas moves in the opposite direction at the end of inspiration. The objective of this study was to apply the method of lung sounds mapping, which is known to provide regional information about gas flow, to study pendelluft in COPD patients. Methods. A 16-channel lung sound analyzer was used to collect sounds from patients with COPD (n = 90) and age-matched normals (n = 90). Pendelluft at the beginning of inspiration is expected to result in vesicular sounds leading the tracheal sound by a few milliseconds. Pendelluft at the end of inspiration is expected to result in vesicular sounds lagging the tracheal sound. These lead and lag times were calculated for the 14 chest wall sites. Results. The lead time was significantly longer in COPD patients: 123 ± 107 ms versus 48 ± 59 ms in controls (P < 0.0001). The lag time was also significantly longer in COPD patients: 269 ± 249 ms in COPD patients versus 147 ± 124 ms in controls (P < 0.0001). When normalized by the duration of the inspiration at the trachea, the lead was 14 ± 13% for COPD versus 4 ± 5% for controls (P < 0.0001). The lag was 28 ± 25% for COPD versus 13 ± 12% for controls (P < 0.0001). Both lead and lag correlated moderately with the GOLD stage (correlation coefficient 0.43). Conclusion. Increased lead and lag times in COPD patients are consistent with the phenomenon of pendelluft as has been observed by other methods.

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“…This suggests that mean nBC is a stable parameter that is not affected by airway clearance techniques, or that it is not responsive to change. Vyshedskiy et al 27 have recently reported on the stability of crackle rate within single examination sessions, despite intervening maximal breathing maneuvers. Recording for 25 second periods provided sufficient data for our crackle analysis.…”

Section: Discussionmentioning

confidence: 99%

Are Crackles an Appropriate Outcome Measure for Airway Clearance Therapy?

Marques

Bruton²,

Barney

et al. 2012

Respir Care

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BACKGROUND: There is an urgent need to develop new outcome measures for respiratory therapy, to evaluate its effectiveness. Adventitious sounds generated from the lungs (crackles and wheezes), can now be quantified and characterized objectively with computer technology. To our knowledge, this is the first reported study designed to assess any change in lung crackles before and after a single session of airway clearance therapy. METHODS: Twenty-three stable bronchiectasis patients were recruited from United Kingdom out-patient clinics and treated with a single session of airway clearance therapy, using the active cycle of breathing technique. Sound recordings were made before and after the session at 7 anatomical chest locations. Computerized lung sound analysis was used to measure crackle parameters: 2-cycle deflection width (2CD), and crackle number per breath cycle (nBC). Perceived breathlessness, lung function, and oxygen saturation data were also recorded. RESULTS: Crackle mean 2CD and mean nBC increased post intervention. Sixteen participants (70%) showed a statistically significant difference in mean crackle 2CD before and after the session at > 1 chest location. Thirteen (57%) participants had a difference between mean crackle 2CD before and after the intervention > 1 Smallest Real Difference (SRD, mean SRD ‫؍‬ 2.23 ms) at > 1 chest location. Differences in mean crackle nBC before and after the intervention did not exceed the SRD (mean SRD ‫؍‬ 32 crackles per breath cycle) in any participant. Perceived breathlessness was significantly reduced post intervention; no significant changes were observed in either lung function or oxygen saturation. CONCLUSIONS: Crackle duration (2CD) was found to change after a single session of airway clearance therapy, and shows promise as a new outcome measure for respiratory therapy interventions.

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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

Cited by 14 publications

References 23 publications

Computerized Respiratory Sounds Are a Reliable Marker in Subjects With COPD

Computerized Respiratory Sounds Are a Reliable Marker in Subjects With COPD

Pendelluft in Chronic Obstructive Lung Disease Measured with Lung Sounds

Are Crackles an Appropriate Outcome Measure for Airway Clearance Therapy?

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