気管音終夜記録の自動解析による睡眠時呼吸異常の検出  [in Japanese] Automated Analysis of All-night Records of Tracheal Sound to Detect Sleep Disordered Breathing  [in Japanese]

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Abstract

睡眠呼吸障害において, 気管音は無呼吸時は消失し, 低呼吸時は周期的変動を呈することが多い. 今回このような気管音変動をパソコンを用いて解析するプログラムを作成し, その診断能に関して検討した. 対象は睡眠呼吸障害を疑い終夜睡眠ポリグラフ (PSG) を施行した33名で, その中でAHI 15以上の例は18例であった. 通常のPSGに加え, 前頸部での気管音をVTRに収録, その気管音終夜記録をA/D変換しパソコンにより自動解析した. 気管音パワーの移動平均曲線の12dB以上の一過性低下をTS-DIP, その中でも背景音+5dB以下になるものをTS-APとして検出した. TS-DIPの回数は無呼吸低呼吸回数と (r=0.95), TS-APの回数は無呼吸回数と (r=0.97) 高い相関を認めた. PSGでのAHI 15以上を陽性としたとき, TS-DIP 15以上を基準とした方法の診断能は, 感度89%・特異度60%であった. 気管音モニタリングは単独でスクリーニング検査として用いることが可能であると考えられる.

In sleep-disordered breathing, tracheal sounds disappear during apnea and vary cyclicly during hypopnea. We tried to detect these changes in tracheal sounds automatically with a personal computer, and we evaluated the diagnostic accuracy of this system for detecting sleep-disordered breathing.<br>Polysomnography and tracheal sound recording were done in 33 subjects with possible sleep apnea/hypopnea syndrome. Eighteen had positive results defined as an apnea/hypopnea index greater than 15. Tracheal sounds were digitized and a personal computer was used to calculate short time power spectra (400-600Hz) every 0.2 seconds by the fast Fourier transform. The moving averages (18 seconds) of the logarithms of the power spectra were calculated every 2 seconds. Transient falls in the moving averages of more than 12dB were detected. Those that were lower than 5dB above the level of background noise were classified as tracheal sound apneas. The number of falls of more than 12dB and the number of tracheal sound apneas correlated strongly with the number of apneas plus hypopneas (r=0.95) and with the number of apneas (r=0.97), respectively. The sensitivity and specificity of tracheal sound analysis for the sleep apnea/hypopnea syndrome (as defined above) were 89% and 60%, respectively, when the criteria was more than 15 falls of more than 12dB per hour.<br>We conclude that tracheal sound analysis by this method is useful as a screening test for the sleep apnea/hypopnea syndrome.

Journal

  • The Japanese journal of thoracic diseases

    The Japanese journal of thoracic diseases 34(7), 765-770, 1996-07-25

    The Japanese Respiratory Society

References:  12

Cited by:  1

Codes

  • NII Article ID (NAID)
    10008110400
  • NII NACSIS-CAT ID (NCID)
    AN00187758
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    03011542
  • Data Source
    CJP  CJPref  J-STAGE 
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