Analysis of breath sounds in normal and asthmatic children and adults using computer digitized airway phonopneumography (CDAP).

Analysis of breath sounds using the stethoscope is a major part of physicians evaluation of their patients. However, the use of a stethoscope is often inadequate to give quantitative measurements of the clinical state of the individual. In this study a modification of a previously described computer analysis of breath sounds was used to measure sound intensity levels in both normal and asthmatic children who, in most cases, were unable to perform pulmonary function. The intensity levels were derived using a microcomputer-based program that digitizes audio signals and calculates energy values at 25-ms intervals throughout each signal. There were statistical differences between mean intensity levels for normal breath sounds in children between 2 and 6 years and the mean intensity levels for wheezing sounds in the same age group, as well as wheezing sounds in asthmatic patients over the age of 8 years (P less than 0.002). Also, the mean intensity levels for normal breath sounds could be clearly differentiated from intensity levels for other sounds from the chest, including heart sounds and voice sounds. Thus, computer digitized airway phonopneumography (CDAP) proved to be a reproducible, quantifiable method for demonstrating airway obstruction in those children and patients unable to perform pulmonary function testing.