Computer bronchophonography - Frequency analysis ofthe respiratory cycle

Abstract

Background: Spirometry is lung function routine test, but it is not always possible to identify the obstruction. Lung sounds (wheezing, cracles) are important diagnostic value.Quantification of lung sounds with the computer program may be an additional lung function test in children. Aim: To introduce the method CBPhG for assessment of lung function in asthmatic children. Materials and methods: CBPhG is method of registration of respiratory sounds, that is recorded by high sensitivity transducer in wide range of frequencies during quiet breathing: low 0,2-1,2, middle >1,2-5,0 and high frequency >5,0 kHz. We evaluated acoustic component of the work of breathing (AC) in mJ. We selected 40 patients (age 6- 16 years) with partly controlled asthma with clinical signs of obstruction confirmed spirometry data. We evaluated CBPG data before and 20 minutes after inhalation of bronchodilators: SABA (salbutamol 200μg), LABA (formoterol 9μg). Initially, there was an increase AC in high-frequency range (reference data 0,11±0.02mJ). Results: FEV1 increased after SABA from 72,5%±3,7% to 82,8%±4,6% (p≤0,004), after LABA – from 79,1%±2,3% to 87,9%±3,4% (p≤0,013). AC decreased in high-frequency zone from 0,33±0,04mJ дo 0,15±0,04mcJ (p=0,001) after SABA, from 0,33±0,05mcJ to 0,18±0,03mcJ (p=0,005) after LABA. Conclusions: CBPhG is a high sensitive method which may be used for assessment of respiratory function in even ages, especially in the childhood. It can be used for evaluation of reversible obstruction.