title: Changes in lung sounds during asthma progression in a guinea pig model.
abstract: BACKGROUND
  Lung sound analysis is useful for objectively evaluating airways even in children with asymptomatic asthma. However, the relationship between lung sounds and morphological changes in the airways has not been elucidated. We examined the relationship between lung sounds and chronic morphological changes in the airways during the progression of asthma from onset in guinea pigs.
  
  
  METHODS
  Eleven male guinea pigs were examined; of these, seven were used as asthma models and four as controls. The asthma models were sensitized and repeatedly challenged by inhaling albumin chicken egg. We measured lung sounds and lung function twice a week for 21 weeks. After the final antigen challenge, the lungs were excised for histological examination. We measured the ratio of airway wall thickness to the total airway area and the ratio of the internal area to the total airway area in the trachea, third bronchi, and terminal bronchioles.
  
  
  RESULTS
  Among the lungs sounds, the difference between the two groups was greatest with respect to inspiratory sound intensity. The ratio of airway wall thickness to the total airway area of the terminal bronchioles was greater in the asthma models than in the controls, and it correlated best with the changes in inspiratory sound intensity in the 501-1000-Hz range (r = 0.76, p < 0.003).
  
  
  CONCLUSIONS
  Lung sound intensity in the middle frequency range from 501 to 1000 Hz correlated with peripheral airway wall thickness. Inspiratory sound intensity appeared to be an indicator of morphological changes in small airways in asthma.
authors: Department of Pediatrics, Minami Wakayama Medical Center, Wakayama, Japan; Department of Mechanical Science & Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan. Electronic address: gd6c-hbkw@asahi-net.or.jp.
authors: Chizu
authors: C
authors: Habukawa
authors: Department of Psychosomatic Medicine, Kinki University Sakai Hospital, Osaka, Japan.
authors: Katsumi
authors: K
authors: Murakami
authors: Department of Mechanical Science & Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan.
authors: Kazuya
authors: K
authors: Sugitani
authors: Department of Mechanical Science & Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan.
authors: Tomohiro
authors: T
authors: Ohtani
authors: Department of Mechanical Science & Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan.
authors: Gabriel Pramudita
authors: GP
authors: Saputra
authors: Department of Mechanical Science & Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan.
authors: Katsuki
authors: K
authors: Kashiyama
authors: Kyoto Pulmonary Center, Rakuwakai Otowa Hospital, Kyoto, Japan.
authors: Yukio
authors: Y
authors: Nagasaka
authors: Department of Mechanical Science & Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan.
authors: Shigeo
authors: S
authors: Wada
mesh_terms: D056151:Airway Remodeling; D000818:Animals; D000941:Antigens / Q000276:immunology; D001249:Asthma / Q000175:diagnosis*; D016022:Case-Control Studies; D004195:Disease Models, Animal; D018450:Disease Progression; D006168:Guinea Pigs; D008168:Lung / Q000473:pathology / Q000503:physiopathology; D008297:Male; D012129:Respiratory Function Tests; D012135:Respiratory Sounds
chemical_list: D000941:Antigens
keywords: Asthma; Bronchi; Guinea pigs; Lung; Respiratory sounds