Ｅｘｅｒｃｉｓｅ‐ｉｎｄｕｃｅｄ ａｓｔｈｍａにおける呼吸性熱喪失および呼吸性水分喪失に関する研究

Abstract

The Phenomenon of exercise-induced asthma (EIA) is commonly observed among the patients with bronchial asthma. Respiratory heat loss (RHL) or respiratory water loss (RWL) is thought to be an initial stimulus responsible for provoking EIA. In order to determine whether dynamic changes in RHL and RWL during exercise have any relation to EIA, nomal controls, EIA(+) asthmatics and EIA(-) asthmatics were examined by an exercise test under exposure to cold atmosphere (5-6°C). The following parameters were measured continuously; convective heat loss (CHL), RWL, evapolative heat loss (EHL), water concentration of expired air, and RHL. Elevation of CHL, EHL, RWL and RHL were observed during exercise. The values of RWL, EHL and RHL were significantly higher in EIA(+) patients than in nomal subjects during exercise. Water concentration of expired air was higher in asthmatics during both rest and exercise. Therefore it was concluded that water loss was greater in EIA(+) asthmatics than in nomal subjects. Since water which is lost from the airway is supplied by the bronchial circulation, it could be assumed that bronchial artery blood flow were greater in EIA(+) asthmatics.