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Changes in the highest frequency of breath sounds without wheezing during methacholine inhalation challenge in

Chizu Habukawa1, Katsumi Murakami, Hiroyuki Mochizuki

  • 1Department of Pediatrics, Minami Wakayama Medical Center, Tanabe, Japan. gd6c-hbkw@asahi-net.or.jp

Respirology (Carlton, Vic.)
|March 10, 2010
PubMed

Insights

A breath sound analyzer detected changes in respiratory sounds during bronchoconstriction. Increased highest frequency of inspiratory breath sounds (HFI) correlated with bronchial reactivity, aiding in detecting airway narrowing.

Area of Science:

  • Pulmonary Medicine
  • Respiratory Physiology
  • Medical Instrumentation

Background:

  • Clinicians face challenges in detecting bronchoconstriction without audible wheezing.
  • Breath sound analysis offers a potential method to identify subtle changes in airway function.
  • This study investigates the utility of a breath sound analyzer in assessing bronchoconstriction.

Purpose of the Study:

  • To determine changes in breath sound frequencies during induced bronchoconstriction and bronchodilation.
  • To evaluate the effectiveness of a breath sound analyzer in quantifying airway narrowing.
  • To correlate breath sound alterations with established measures of bronchial reactivity.

Main Methods:

  • Thirty-six children underwent spirometry, methacholine challenge, and breath sound analysis.
  • Respiratory resistance, bronchial sensitivity, and bronchial reactivity were assessed.
  • Highest frequency of inspiratory (HFI) and expiratory (HFI) breath sounds were measured before and after methacholine and bronchodilator administration.

Main Results:

  • Methacholine-induced bronchoconstriction led to a significant increase in HFI (P < 0.001).
  • Post-bronchodilator HFI returned to baseline levels, significantly lower than peak levels (P < 0.001).
  • The percentage change in HFI correlated significantly with the speed of bronchoconstriction (P = 0.007).

Conclusions:

  • Methacholine-induced bronchoconstriction significantly elevates HFI.
  • The increase in HFI is directly correlated with bronchial reactivity.
  • Breath sound analysis can objectively quantify changes associated with bronchoconstriction.
Abstract

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