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气管音谱取决于身高。

Tracheal sound spectra depend on body height.

作者信息

Sanchez I, Pasterkamp H

机构信息

Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada.

出版信息

Am Rev Respir Dis. 1993 Oct;148(4 Pt 1):1083-7. doi: 10.1164/ajrccm/148.4_Pt_1.1083.

Abstract

Tracheal sounds originate from turbulent flow in upper and central airways. Turbulent flow characteristics are influenced by conduit dimensions. Because tracheal dimensions are a function of body height, we hypothesized that there should be a correlation between sound spectra and body length. We recorded tracheal sounds at standardized airflows in 21 healthy children 9.1 +/- 0.6 yr of age (mean +/- SE) and in 24 healthy adults 30.2 +/- 0.8 yr of age. A contact sensor was attached at the suprasternal notch of the sitting subject, and airflow was measured at the mouth with a calibrated pneumotachograph. Tracheal sounds were low-pass-filtered at 2.4 kHz and digitized at 10 kHz. A 2048 point FFT was applied at a successive 100-ms intervals, using a Hanning data window. Resulting spectra were normalized to a reference power of 0.1 (mV)2/5 Hz. We applied a gating algorithm to extract sounds at inspiratory flows of 1 L/s (+/- 10% tolerance), and we computed average power spectra from the collected samples. We calculated the average spectral power (Pavg), the quartile frequencies below which 25% (Q1), 50% (Q2), and 75% (Q3) of the power in the range of 50 to 2,000 Hz was contained, the spectral edge frequency (SE95) below which 95% of the power was found, and the frequency where spectral power rolled off sharply (Fcut).(ABSTRACT TRUNCATED AT 250 WORDS)

摘要

气管声音起源于上呼吸道和中央气道的湍流。湍流特性受管道尺寸影响。由于气管尺寸是身高的函数,我们推测声音频谱与身体长度之间应该存在相关性。我们在标准化气流条件下,记录了21名9.1±0.6岁(平均±标准误)的健康儿童和24名30.2±0.8岁的健康成年人的气管声音。将接触式传感器附着在坐着受试者的胸骨上切迹处,并用校准的呼吸流速仪在口腔测量气流。气管声音在2.4kHz处进行低通滤波,并以10kHz进行数字化。使用汉宁数据窗,以连续100ms的间隔应用2048点快速傅里叶变换(FFT)。将所得频谱归一化为0.1(mV)2/5Hz的参考功率。我们应用门控算法提取吸气流量为1L/s(±10%容差)时的声音,并从收集的样本中计算平均功率谱。我们计算了平均频谱功率(Pavg)、50至2000Hz范围内25%(Q1)、50%(Q2)和75%(Q3)的功率所对应的四分位数频率、95%的功率所对应的频谱边缘频率(SE95)以及频谱功率急剧下降的频率(Fcut)。(摘要截断于250字)

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