[Effects of 21 d -6 degrees head down bed-rest on pulmonary gas distribution and little airway function].

OBJECTIVE: To probe the effect of 21 d -6 degrees head down bed-rest (HDBR) on pulmonary gas distribution and little airway function. METHOD: The indices of the pulmonary gas distribution and little airway function (delta N2, CV, CV/VC%, LCI) were measured in 16 healthy male subjects before, during and after 21 d -6 degrees HD-BR. RESULT: Comparing with before and early days of HDBR, recovery supine delta N2 increased significantly. CV increased significantly only on the first day of HDBR, and changes of CV/VC% were same as CV. The changes of LCI were not significant. CONCLUSION: The indices of pulmonary gas distribution were affected by 21 d -6 degrees HDBR. Pulmonary gas distribution was more uneven during and after 21 d -6 degrees HDBR.