Department of Pediatrics, Minami Wakayama Medical Center, Tanabe, Japan.
Respirology. 2010 Apr;15(3):485-90. doi: 10.1111/j.1440-1843.2010.01706.x. Epub 2010 Feb 24.
It is difficult for clinicians to identify changes in breath sounds caused by bronchoconstriction when wheezing is not audible. A breath sound analyser can identify changes in the frequency of breath sounds caused by bronchoconstriction. The present study aimed to identify the changes in the frequency of breath sounds during bronchoconstriction and bronchodilatation using a breath sound analyser.
Thirty-six children (8.2 +/- 3.7 years; males : females, 22 : 14) underwent spirometry, methacholine inhalation challenge and breath sound analysis. Methacholine inhalation challenge was performed and baseline respiratory resistance, minimum dose of methacholine (bronchial sensitivity) and speed of bronchoconstriction in response to methacholine (Sm: bronchial reactivity) were calculated. The highest frequency of inspiratory breath sounds (HFI), the highest frequency of expiratory breath sounds (HFE) and the percentage change in HFI and HFE were determined. The HFI and HFE were compared before methacholine inhalation (pre-HFI and pre-HFE), when respiratory resistance reached double the baseline value (max HFI and max HFE), and after bronchodilator inhalation (post-HFI and post-HFE).
Breath sounds increased during methacholine-induced bronchoconstriction. Max HFI was significantly greater than pre-HFI (P < 0.001), and decreased to the basal level after bronchodilator inhalation. Post-HFI was significantly lower than max HFI (P < 0.001). HFI and HFE were also significantly changed (P < 0.001). The percentage change in HFI showed a significant correlation with the speed of bronchoconstriction in response to methacholine (P = 0.007).
Methacholine-induced bronchoconstriction significantly increased HFI, and the increase in HFI was correlated with bronchial reactivity.
当哮鸣音不可闻时，临床医生难以识别由支气管收缩引起的呼吸音变化。呼吸音分析仪可以识别由支气管收缩引起的呼吸音频率变化。本研究旨在使用呼吸音分析仪识别支气管收缩和支气管扩张时呼吸音频率的变化。
36 名儿童（8.2 +/- 3.7 岁；男：女，22:14）接受了肺量测定、乙酰甲胆碱吸入挑战和呼吸音分析。进行了乙酰甲胆碱吸入挑战，并计算了基础呼吸阻力、乙酰甲胆碱的最小剂量（支气管敏感性）和对乙酰甲胆碱的支气管收缩速度（Sm：支气管反应性）。确定了吸气呼吸音的最高频率（HFI）、呼气呼吸音的最高频率（HFE）以及 HFI 和 HFE 的百分比变化。在乙酰甲胆碱吸入前（预 HFI 和预 HFE）、呼吸阻力达到基础值的两倍时（最大 HFI 和最大 HFE）以及支气管扩张剂吸入后（后 HFI 和后 HFE）比较 HFI 和 HFE。
呼吸音在乙酰甲胆碱引起的支气管收缩期间增加。最大 HFI 明显大于预 HFI（P < 0.001），并在支气管扩张剂吸入后降至基础水平。后 HFI 明显低于最大 HFI（P < 0.001）。HFI 和 HFE 也发生了显著变化（P < 0.001）。HFI 的百分比变化与对乙酰甲胆碱的支气管收缩速度呈显著相关性（P = 0.007）。
乙酰甲胆碱引起的支气管收缩显著增加了 HFI，HFI 的增加与支气管反应性相关。
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