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Chest surface mapping of lung sounds during methacholine challenge
H Pasterkamp1, R Consunji-Araneta, Y Oh
1Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada.
Pediatric Pulmonology
|January 1, 1997
Summary
Changes in normal lung sounds, not wheezing, can indicate airway narrowing in asthma. These subtle lung sound alterations occur early during methacholine challenges and reverse with treatment.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Biomedical Engineering
Background:
- Wheezing is an unreliable indicator of airway obstruction during bronchoprovocation.
- Asthma diagnosis and monitoring require sensitive methods to detect early airway changes.
Purpose of the Study:
- To investigate if changes in normal (vesicular) lung sounds can detect airway narrowing.
- To assess the sensitivity of lung sounds to early airway caliber changes in pediatric asthma.
Main Methods:
- A standardized methacholine challenge was administered to 15 children with asthma and 9 healthy controls (aged 8-16).
- Respiratory sounds were recorded using eight contact sensors placed on the chest and trachea.
- Spectral analysis of normal inspiratory and expiratory lung sounds was performed at specific airflow rates.
Main Results:
- Significant changes in lung sound spectra, but not tracheal sounds, were observed during airway narrowing.
- Inspiratory lung sounds showed decreased power at low frequencies, while expiratory sounds had increased power at high frequencies.
- These lung sound alterations occurred with less than a 10% decrease in forced expiratory volume in 1 second and were reversible with salbutamol.
Conclusions:
- Normal lung sounds are sensitive to changes in airway caliber during bronchoprovocation in children.
- Lung sound analysis may offer an early, albeit non-specific, indicator of airway narrowing in asthma.
- Further research is needed to explore the specificity and clinical application of lung sound analysis in asthma management.