0
Original Research |

Mechanism of Inspiratory and Expiratory Crackles

Andrey Vyshedskiy, PhD*; Ruqayyah M. Alhashem; Rozanne Paciej; Margo Ebril; Inna Rudman; Jeffrey J. Fredberg, PhD; Raymond Murphy, MD, ScD, FCCP
Author and Funding Information

*From the Brigham and Women's/Faulkner Hospitals, Boston University, and Harvard School of Public Health, Boston, MA.

Correspondence to: Andrey Vyshedskiy, PhD, 1153 Centre St, Suite 4990, Boston, MA 02130; e-mail: av@stethographics.com

*Data are presented as average ± SD. This study has only included patients with very high number of crackles; this study was not designed to predict average numbers of crackles in the different disease categories. For the information on differences in crackle rate in different disease categories, see Murphy.6

This work was supported in part by grants from the National Institutes of Health, Small Business Innovation Research (1R43HL70480-01) and from Stethographics, Inc.

Dr. Murphy and Dr. Vyshedskiy have financial interests in Stethographics, Inc.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).


This work was supported in part by grants from the National Institutes of Health, Small Business Innovation Research (1R43HL70480-01) and from Stethographics, Inc.

This work was supported in part by grants from the National Institutes of Health, Small Business Innovation Research (1R43HL70480-01) and from Stethographics, Inc.

Dr. Murphy and Dr. Vyshedskiy have financial interests in Stethographics, Inc.

Dr. Murphy and Dr. Vyshedskiy have financial interests in Stethographics, Inc.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).


Chest. 2009;135(1):156-164. doi:10.1378/chest.07-1562
Text Size: A A A
Published online

Objective:  Although crackles are frequently heard on auscultation of the chest of patients with common cardiopulmonary disorders, the mechanism of production of these sounds is inadequately understood. The goal of this research was to gain insights into the mechanism of crackle generation by systematic examination of the relationship between inspiratory and expiratory crackle characteristics.

Methods:  Patients with a significant number of both inspiratory and expiratory crackles were examined using a multichannel lung sound analyzer. These patients included 37 with pneumonia, 5 with heart failure, and 13 with interstitial fibrosis. Multiple crackle characteristics were calculated for each crackle, including frequency, amplitude, crackle transmission coefficient, and crackle polarity.

Results:  Spectral, temporal, and spatial characteristics of expiratory and inspiratory crackles in these patients were found to be similar, but two characteristics were strikingly different: crackle numbers and crackle polarities. Inspiratory crackles were almost twice as numerous as expiratory crackles (n = 3,308 vs 1,841) and had predominately negative polarity (76% of inspiratory crackles vs 31% of expiratory crackles).

Conclusion:  These observations are quantitatively consistent with the so-called stress-relaxation quadrupole hypothesis of crackle generation. This hypothesis holds that expiratory crackles are caused by sudden airway closure events that are similar in mechanism but opposite in sign and far less energetic than the explosive opening events that generate inspiratory crackles. We conclude that the most likely mechanism of crackle generation is sudden airway closing during expiration and sudden airway reopening during inspiration.

Figures in this Article

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Figures

Tables

References

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Related Content

Customize your page view by dragging & repositioning the boxes below.

CHEST Journal Articles
PubMed Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543