Clinical application of a lung sound analysis in infants with respiratory syncytial virus acute bronchiolitis.

BACKGROUND: Objective investigation of the characteristics of acute bronchiolitis in infants is important for its diagnosis and treatment. METHODS: Lung sound data of 50 patients diagnosed with respiratory syncytial virus (RSV) acute bronchiolitis (m:f = 29:21, median of age 7 months), 20 patients with RSV acute respiratory tract infections without acute bronchiolitis (m:f = 10:10, 5 months) and 38 age-matched control infants (m:f = 23:15, 8 months) were analyzed using a conventional method and compared. Furthermore, the relationships between lung sound parameters and clinical symptoms (clinical score, length of hospital stay and SpO2 level) in the bronchiolitis and the non-bronchiolitis patients were examined. RESULTS: Results of lung sound analysis showed that the inspiratory sound power of patients with RSV respiratory tract infections was low and the expiratory sound power was high compared with those of the controls. When the patients with RSV respiratory tract infections were divided into the bronchiolitis and non-bronchiolitis groups, the expiratory/inspiratory ratio of the bronchiolitis patients was greater than that of the non-bronchiolitis patients. There was no difference in the clinical symptoms, clinical score and length of hospital stay between the bronchiolitis and non-bronchiolitis patients, except for the SpO2 level on admission. CONCLUSION: Lung sound analysis confirmed that patients with RSV acute bronchiolitis present with marked airway narrowing. Considering these results as a characteristic of acute bronchiolitis, it would be meaningful to reflect it in the improvement of diagnosis, treatment and subsequent management.

Effect of wheeze and lung function on lung sound parameters in children with asthma.

BACKGROUND: In children with asthma, there are many cases in which wheeze is confirmed by auscultation with a normal lung function, or in which the lung function is decreased without wheeze. Using an objective lung sound analysis, we examined the effect of wheeze and the lung function on lung sound parameters in children with asthma. METHODS: A total of 114 children with asthma (males to females = 80: 34, median age 10 years old) were analyzed for their lung sound parameters using conventional methods, and wheeze and the lung function were checked. The effects of wheeze and the lung function on lung sound parameters were examined. RESULTS: The patients with wheeze or decreased forced expiratory flow and volume in 1 s (FEV1) (% pred) showed a significantly higher sound power of respiration and expiration-to-inspiration sound power ratio (E/I) than those without wheeze and a normal FEV1 (% pred). There was no marked difference in the sound power of respiration or E/I between the patients without wheeze and a decreased FEV1 (% pred) and the patients with wheeze and a normal FEV1 (% pred). CONCLUSIONS: Our data suggest that bronchial constriction in the asthmatic children with wheeze similarly exists in the asthmatic children with a decreased lung function. A lung sound analysis is likely to enable an accurate understanding of airway conditions.

[EFFECT OF INSPIRATORY FLOW ON BREATH SOUND ANALYSIS IN CHILDREN WITH ASTHMA].

BACKGROUND: In order to determine the optimal breathing method for childhood lung sound analyses, it is important to study the effect of airflow on the parameters of lung sounds. METHODS: Sixty-one well-controlled children with atopic asthma (median; 12 years) participated. After confirming that there was no wheezing or respiratory symptoms, the lung sound spectrums of the inspiratory flow before and after inhalation of a ß2 stimulant were analyzed. At the same time, their lung function was measured by a spirogram and the forced oscillation technique. RESULTS: Before ß2 agonist inhalation, the area under the entire curve (AT) and 99% frequency (F99) in the lung sound of inspiratory flow around 2.0L/s due to slightly strong breathing were significantly higher than the lung sound of inspiratory flow around 1.0L/s due to rest breathing. However, no marked differences were observed in the lung sound parameters based on the lung sound spectrum. The improvement in the lung sound parameters after ß2 agonist inhalation was clearer at an inspiratory flow around 1.0L/s than that around 2.0L/s. CONCLUSION: The present study showed that changes after ß2 agonist inhalation and the correlation with the lung function parameters were clear during resting breathing. This method may be used for the long-term montoring of children with asthma.