Characteristics of breath sound in infants with risk factors for asthma development.

BACKGROUND: Breath sound parameters have been suggested as biomarkers of the airway narrowing in children. Using a commercially available breath sound analyzer, the characteristics of the airway condition were investigated in infants with the risk factors for asthma development. METHODS: A total of 443 infants (mean age, 9.9 months; range, 3-24 months) were included in the present study. The breath sound parameters of the frequency limiting 99% of the power spectrum (F99), the roll-off from 600 to 1200 Hz (Slope) and spectrum curve indices, the total area under the curve of the dBm data (A3/AT) and the ratio of power and frequency at 50% and 75% of the highest frequency of the power spectrum (RPF75 and RPF50), were evaluated. Using an ATS-DLD based original Japanese questionnaire, we examined the characteristics of airway condition of infants. RESULTS: Finally, 283 infants in good health were included in the present study. The RPF75, RPF50, Slope and F99 in infants with positive results of allergy and atopic dermatitis were significantly increased more than those in the infants with negative result. CONCLUSIONS: Our data highlight the characteristics of breath sounds in infants with risk factors for asthma. The breath sound analysis may be useful for assessing the airways of infants for asthma development.

Severity of respiratory signs and symptoms and virus profiles in Japanese children with acute respiratory illness.

Associations between the severity of respiratory signs and symptoms and the respiratory viruses identified in 214 Japanese children with acute respiratory illness (ARI) enrolled between January and December 2012 were studied. Respiratory rate, wheezing, cyanosis, and the use of accessory muscles were used as indices of respiratory severity and phylogenetic analysis of the viruses identified in these children was performed. Respiratory viruses such as respiratory syncytial virus (RSV), human rhinovirus (HRV), human parainfluenza virus (HPIV), and human metapneumovirus (HMPV) were prevalent, being detected in approximately 70% of the patients (151/214 patients). Co-detection of viruses occurred in about 9% of patients. RSV was identified more frequently in cases scored as moderate/severe than in those scored as mild (P < 0.05). Severity scores of patients with RSV were significantly higher than those of cases with HPIV. Moreover, severity scores in patients with mild disease and co-detections were higher than in those in whom only HPIV or adenovirus was detected. Phylogenetic analysis showed that many genotypes of HRV-A and -C with wide genetic divergence were associated with acute respiratory illness (ARI). On the other hand, only a limited number of genotypes of RSV were associated with ARI. HPIV and HMPV were associated with ARI at similar frequencies. These results suggest that different respiratory viruses with unique genetic characteristics can be found in patients with mild to severe ARI.

A Lung Sound Analysis in Infants with Risk Factors for Asthma During Acute Respiratory Infection.

Background: The parameters of lung sounds have been suggested as biomarkers of airway changes. Using a commercially available lung sound analyzer, we investigated the characteristics of the lung sounds in infants with acute respiratory infection (ARI). Methods: Infants with ARI who were 6 to 18 months of age were included in this study. The lung sound parameters, the ratio of the third area and fourth areas to the total area under the curve of the sound spectrum (A3/AT and B4/AT), and the ratio of power and frequency at 75% and 50% of the highest frequency of the power spectrum (RPF75 and RPF50) were evaluated. With an original Japanese questionnaire based on American Thoracic Society-Division of Lung Disease, the risk factors of asthma development in infants were examined. Results: One hundred ten infants with ARI and 248 infants in good health for comparison were included. All infants were completely analyzed, and then divided into 2 age groups for a stratification analysis (6-12 and 13-18 months). In the overall analysis, among infants with a history of wheezing, recurrent wheezing, allergy, and atopic dermatitis, the values of RPF50 of infants with ARI were significantly lower compared with those without ARI. In the 6- to 12-month-old group, the RPF50 values of atopy-positive infants with ARI were lower compared with those without ARI (P = 0.003). Conclusions: The lung sounds of the infants with asthma-developing risk factors were more affected by ARI than those of infants without risk factors. Analyzing the changes in the lung sounds induced by ARI may be useful for evaluating the characteristics of the airways in infants.