Difference of breath sound spectrum between healthy children and children with cough variant asthma

Cough variant asthma (CVA) is a specific asthma phenotype, and wheezing or abnormal breathing sounds are rarely heard in CVA patients during traditional auscultation. This study aimed to use a standardized electronic stethoscope to assess whether there are differences in breath sounds between healthy children and children with CVA. Thirty-five healthy children (476 segments of the inspiratory phase) and nineteen children with CVA (244 segments of the inspiratory phase) participated. A comparative analysis was conducted on the breath sound parameters, including the area under the curve (AUC), the secant slope, and the power of the sound spectrum (decibel, dB), between healthy children and children with CVA. For further comparative analysis, children with CVA were divided into two subgroups based on allergy grades and pulmonary function (PF) statuses: allergy grade < = 2 groups vs. allergy grade > = 3 group, normal PF group vs. abnormal PF group. Statistical analyses were completed using the SPSS software. This study demonstrated that the AUC, the secant slope, and the dB values in children with CVA were higher than those in healthy children. Children with CVA whose allergy grade > = 3 had a higher secant slope value at 700–1700 Hz and higher dB values at 1100 Hz, 1300 Hz, and 1500 Hz. In the abnormal PF group, the dB values at 1300 Hz and 1700 Hz are lower in children with CVA. This study proved that children with CVA have abnormal sounds that traditional auscultation methods cannot identify. Meanwhile, both allergy grade and PF status can affect breath sounds.