Background : We have established a 15-seconds tidal breathing method using our originally developed apparatus to measure cough sensitivity to capsaicin. Astograph, an apparatus to measure bronchial re-sponsiveness to methacholine, has been widely used in clinical practice in Japan. If Astograph is available for measurement of cough sensitivity, it will contribute to promoting the spread of cough sensitivity test.
Methods : Fifteen-seconds tidal breathing methods using our original apparatus and Astograph were compared in 29 healthy subjects. To assess the agreement of the two methods, increasing concentrations of capsaicin solution were inhaled for 15 seconds until 5 or more cough were elicited and cough threshold, the lowest concentration of capsaicin eliciting 5 or more coughs, was determined by each method on 2 separate days at one week interval. On each day, the cough threshold measurement was repeated twice at one-hour interval to assess the repeatability.
Results : Difference and repeatability coefficient were 0.35 and 2.00 in our original method and 0.14 and 1.88 doubling concentration in Astograph method, respectively, indicating good repeatability of both methods. Difference and coefficient of agreement between the two methods was 0.30 and 2.44 doubling concentration, respectively.
Conclusions : Astograph is suitable for measurement of cough sensitivity to capsaicin because of its good repeatability and agreement with our original method already established.
[Rinsho Byori 50 : 410〜414, 2002]
*1Department of Laboratory, Kanazawa University Hospital, Kanazawa 920-8641
【Key Words】cough sensitivity(咳感受性)，tidal breathing method(安静換気法)，astograph method(アストグラフ法)，capsaicin(カプサイシン)，repeatability(再現性)
近年，慢性の咳嗽，とくに乾性咳嗽のみを訴える患者が増加しており，咳嗽の診断および治療は呼吸
器臨床の重大な問題となっている。慢性咳嗽の原因疾患の診断と治療効果の判定に，咳感受性測定は有
受付2001年7月26日・受理2002年1月18日
*1〜3金沢大学医学部附属病院検査部，
*4金沢大学医学部臨床検査医学，*5同 麻酔学，*6同 呼吸器内科(〒920-8641 金沢市宝町13-1)