Objective evaluation of wheezing in normal infants

Abstract

Background: To evaluate the frequency of wheezing in infants, the presence of wheezing was examined in normal infants using a breath sound analyzer, Methods: A total of 443 infants (age range, 3-24 months) were included in the present study. The existence of audible wheezing and faint wheezing/inaudible wheezing-like noises (FW) was confirmed on chest auscultation and a sound spectrogram. The breath sound parameters of the sound spectrum, frequency limiting 99% of power spectrum (F 99 ), roll-off from 600 to 1,200 Hz (slope) and spectrum curve indices, total area under the curve of dB data (A 3 /A T and B 4 /A T ), and ratio of power and frequency at 50% and 75% of the highest frequency of the power spectrum (RPF 50 and RPF 75 ) were calculated. Using an original Japanese questionnaire, we examined the characteristics of the airway condition of all infants. Results: Finally, a total of 398 infants were analyzed in the present study, and 283 were in good health while 115 had acute respiratory infection (ARI) in the last 7 days. No infants had audible wheezing on auscultation. Three infants without ARI (1.1%) and 10 infants with ARI (8.7%) had FW. In the evaluation of breath sound parameters, there were no marked differences between the infants with and without FW. Conclusions: Using a breath sound analyzer, wheezing and FW were recognized in only a few infants in good health. Infants recognized to have audible wheezing in daily practice may be at risk of developing recurrent wheezing/asthma. A total of 443 infants (mean age, 9.9 months; range, 3-24 months, male : female, 232:211) who attended an infant

Breath sound analyses of infants with respiratory syncytial virus acute bronchiolitis

“…Widely, acute bronchiolitis is known to cause wheeze, 2 which are musical, continuous‐expiratory sounds, 30,31 but our data included fewer patients with wheeze than previous reports on breath sounds 25,26 . Typical wheeze are easy to identify as a sinusoidal waveform in the breath sound spectrogram 27 . However, based on examination of breath sound spectrograms, the expiratory sounds may differ from the waveform sounds of wheeze which commonly found in asthmatic children.…”

“…In the present study, of note, the breath sound spectrogram of expiration in acute bronchiolitis was found to be characteristic. As previously mentioned, 25,26 the breath sounds of acute phase of acute bronchiolitis show marked power that is not observed in the breath sound spectrogram of healthy children 27 or children with mild exacerbation of asthma. 19 According to reports of the pathophysiology, 28 epithelial damage and desquamation that introduce clusters of desquamated epithelial cells and viscous sputum 29 are severe in the patients with acute bronchiolitis.…”

“…25,26 Typical wheeze are easy to identify as a sinusoidal waveform in the breath sound spectrogram. 27 However, based on examination of breath sound spectrograms, the expiratory sounds may differ from the waveform sounds of wheeze which commonly found in asthmatic children. We suspect that the nonuniform, band-like sounds in the low-pitched area seen in Figure 1 were heard as rhonchi.…”

Breath sound analyses of infants with respiratory syncytial virus-induced acute bronchiolitis

“…In the present study, of note, the breath sound spectrogram of expiration in acute bronchiolitis was found to be characteristic. As previously mentioned 25,26) , the breath sounds of acute phase of acute bronchiolitis show marked power that is not observed in the breath sound spectrogram of healthy children 27) or children with mild exacerbation of asthma 16) . According to reports of the pathophysiology 28) , epithelial damage and desquamation that introduce clusters of desquamated epithelial cells and viscous sputum 29) are severe in the patients with acute bronchiolitis.…”

“…Widely, acute bronchiolitis is known to cause wheezes 2) , which are high-pitched continuousexpiratory sounds 30) , but our data included fewer patients with wheezes than previous reports on breath sounds 25,26) . Typical rhonchi and wheezes are continuous musical sounds 31) that are easy to identify as a sinusoidal waveform in the breath sound spectrogram 27) . However, based on examination of breath sound spectrograms, the expiratory sounds may differ from the waveform sounds of rhonchi and wheezes which commonly found in asthmatic children.…”