Respiratory sound energy and its distribution patterns following clinical improvement of congestive heart failure: a pilot study.

Zhen Wang,Brigitte M Baumann,Karen Slutsky,Smith Jean,Karen N Gruber

doi:10.1186/1471-227x-10-1

Abstract

BackgroundAlthough congestive heart failure (CHF) patients typically present with abnormal auscultatory findings on lung examination, respiratory sounds are not normally subjected to additional analysis. The aim of this pilot study was to examine respiratory sound patterns of CHF patients using acoustic-based imaging technology. Lung vibration energy was examined during acute exacerbation and after clinical improvement.MethodsRespiratory sounds throughout the respiratory cycle were captured using an acoustic-based imaging technique. Twenty-three consecutive CHF patients were imaged at the time of presentation to the emergency department and after clinical improvement. Digital images were created (a larger image represents more homogeneously distributed vibration energy of respiratory sound). Geographical area of the images and respiratory sound patterns were quantitatively analyzed. Data from the CHF patients were also compared to healthy volunteers.ResultsThe median (interquartile range) geographical areas of the vibration energy image of acute CHF patients without and with radiographically evident pulmonary edema were 66.9 (9.0) and 64.1(9.0) kilo-pixels, respectively (p < 0.05). After clinical improvement, the geographical area of the vibration energy image of CHF patients without and with radiographically evident pulmonary edema were increased by 18 ± 15% (p < 0.05) and 25 ± 16% (p < 0.05), respectively.ConclusionsWith clinical improvement of acute CHF exacerbations, there was more homogenous distribution of lung vibration energy, as demonstrated by the increased geographical area of the vibration energy image.

Highlights

Congestive heart failure (CHF) patients typically present with abnormal auscultatory findings on lung examination, respiratory sounds are not normally subjected to additional analysis
The geographical area in congestive heart failure (CHF) patients without and with radiographically evident pulmonary edema (REPE) was significantly lower compared to the geographical area of healthy volunteers (p < 0.05)
Total vibration energy decreased in CHF patients with REPE following clinical improvement by an average of 90 ± 11% (p < 0.01) but remained unchanged in CHF patients without REPE (Figure 6)

Summary

Introduction

Congestive heart failure (CHF) patients typically present with abnormal auscultatory findings on lung examination, respiratory sounds are not normally subjected to additional analysis. The theory behind using this type of analysis is that diseases affecting the lungs would result in alterations of lung vibration energy that may be too subtle to be detected on the skin surface using conventional methods. These altered vibrations may be due to changes in amount of vibration created due to increase or decrease in airflow, changes in the transmission of vibrations through the diseased lung parenchyma, or pleural space and heterogeneity of disease throughout the lung [3,4,5,6,7]

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Results

Discussion

Conclusion