PT  - JOURNAL ARTICLE
AU  - P.M. Gustafsson
AU  - H.K. Ljungberg
AU  - B. Kjellman
TI  - Peripheral airway involvement in asthma assessed by single-breath SF<sub>6</sub> and He washout
AID  - 10.1183/09031936.03.00049302
DP  - 2003 Jun 01
TA  - European Respiratory Journal
PG  - 1033--1039
VI  - 21
IP  - 6
4099  - http://erj.ersjournals.com/content/21/6/1033.short
4100  - http://erj.ersjournals.com/content/21/6/1033.full
SO  - Eur Respir J2003 Jun 01; 21
AB  - The aim of the study was to assess how deep into the acinar region the airway response to cold dry-air hyperventilation challenge (CACh) reaches in subjects with asthma of different severity. Peripheral airway function was measured using a single-breath sulphur hexafluoride (SF6) and helium (He) washout test and overall airway function by forced expiratory volume in one second (FEV1) at rest, after CACh and β2-therapy in 55 adults with a history of asthma. The normalised phase-III slopes (SnIII) for SF6 and He were used to assess peripheral airway obstruction and the (SF6-He) SnIII difference to indicate where obstruction occurred. While a greater He versus SF6 slope increase indicates a response close to the acinar entrance, the reverse indicates a response deeper into the acinar airspaces. Twelve subjects had a major fall in FEV1 (≥20%) after CACh, 16 a minor fall (10–19%), and 27 did not react. Resting He and SF6 SnIII were significantly greater in major responders with respect to minor and nonresponders, while resting FEV1 did not differ between the three groups. The major responders showed marked increases of He and SF6 SnIII after CACh, with greater increase for He resulting in a negative (SF6-He) SnIII difference. To conclude, airways close to the acinar entrance participate in the overall airway response to cold-air challenge in asthmatic adults with marked airway hyperresponsiveness to cold, dry air. This study was supported by the Research and Development Council, Central Hospital, Skövde, Sweden.