Journal of Asthma and Allergy (Oct 2019)
Lung Sound Analysis Provides A Useful Index For Both Airway Narrowing And Airway Inflammation In Patients With Bronchial Asthma
Abstract
Terufumi Shimoda,1,2 Yasushi Obase,3 Yukio Nagasaka,4 Reiko Kishikawa,2 Sadahiro Asai1 1Department of Allergy, San Remo Rehabilitation Hospital, Sasebo, Japan; 2Department of Allergy, Clinical Research Center, Fukuoka National Hospital, Fukuoka, Japan; 3Department of Respiratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan; 4Department of Respiratory Medicine, Kyoto Respiratory Center, Otowa Hospital, Kyoto, JapanCorrespondence: Terufumi ShimodaDepartment of Allergy, San Remo Rehabilitation Hospital, l4848-1 Egamicho, Sasebo 859-3244, JapanTel +81-956-58-5900Fax +81-956-58-5550Email [email protected]: The expiration-to-inspiration sound power ratio in a midfrequency range (E/I MF), a parameter of lung sound analysis (LSA), has been reported to be useful as an index of airway inflammation in patients with bronchial asthma. However, the E/I MF reflects airway narrowing caused by airway inflammation, and there is thus concern that it may not be an index of airway eosinophilic inflammation itself.Methods: A total of 131 patients with bronchial asthma were classified into four groups according to the presence or absence of airway narrowing and airway inflammation to examine whether the E/I MF could serve as an index of airway inflammation.Results: The E/I MF was significantly higher in patients with a normal forced expiratory volume in one second (FEV1) and high fractional exhaled nitric oxide (FeNO), those with a low FEV1 and normal FeNO, and those with a low FEV1 and high FeNO than in those with a normal FEV1 and normal FeNO (p < 0.05–0.01). In particular, the E/I MF was high even in the patients who had no airway narrowing but had airway inflammation (p < 0.01). The results of multivariate analysis of factors involved in FeNO in patients with a normal FEV1 revealed that the E/I MF was an independent factor (p = 0.0281).Conclusion: The E/I MF is a useful index of airway inflammation in the treatment of asthma, regardless of the presence or absence of airway narrowing.Keywords: airway inflammation, bronchial asthma, E/I MF, FeNO, lung sound analysis
