3.2, The Evaluation of the breath sound spectrogram
On comparing the respiratory sounds of patients in the recovery period
and a seven-month-old healthy infant from a previous
study15) to those of patientsint the acute phase of
acute bronchiolitis, the sound power of inspiration and expiration in
the acute phase were great, especially that of expiration (Figure 1).
An examination of the breath sound spectrogram images of all the
patients showed sinusoidal waveforms of wheezes (>400 Hz,
>200mS) in 11 (33 %), sinusoidal waveforms of rhonchi
(≤200 Hz, >200mS) in 7 (21 %), and non-uniform, granular
bands suggesting strong power in the low-pitched region of the
expiratory spectrum (Figure 1) in 20 (61%, 5 cases overlapped with
wheezes or rhonchi). As a typical case of this sound, the sound spectrum
on expiration in one patient showed a waveform with several peaks
(Figure 2).