AIRWAY RESPONSIVENESS TO HYPEROSMOLAR SALINE CHALLENGE IN CYSTIC-FIBROSIS - A PILOT-STUDY

Hyperosmolar aerosols are used to assess airway responsiveness in subj ects with asthma. Using a 10% NaCl aerosol, we investigated airway res ponsiveness in 23 cystic fibrosis (CF) subjects (12 females, 11 males; 19.1 +/- 3.3 years) who had asthma-like symptoms. The pre-challenge p redicted forced expiratory volume in 1 second (FEV(1)) was 74.7 +/- 21 .5. The aerosol was generated by a MistO(2)gen 143A ultrasonic nebuliz er and inhaled for 0.5, 1, 2, 4, 8, 8, and 8 minutes or part thereof. Spirometry was performed before and 1 minute after each inhalation per iod. The challenge was stopped when a greater than or equal to 20% fal l from the baseline FEV(1) was recorded, after the last inhalation per iod, or when requested by the subject. We recorded different responses to 10% NaCl among subjects. In 7, the FEV(1) fell progressively throu ghout the challenge in a manner similar to asthmatics. By contrast, in 15 subjects the FEV(1) was higher at the completion of challenge comp ared to during challenge, i.e., the fall in FEV(1) was transient. In 7 of these subjects, the final FEV(1) at the end of the challenge was h igher than the pre-challenge FEV(1). We conclude that inhaled 10% hype rosmolar saline causes either progressive and sustained or transient a irway narrowing during challenge in the majority of CF subjects. The c ause of the transient airway narrowing requires further investigation. (C) 1996 Wiley-Liss, Inc.