[Simultaneous recording of spirometric parameters and total respiratory resistance on the Astograph in nonspecific...

Parallel study results of spirometric parameters (S.P.) FEV1, FEF50, FEF25 and total respiratory resistance (Rrs) measured by Astograph in nonspecific metacholine bronchoprovocation test were analyzed in 378 patients suspected of bronchial asthma. The patients were divided into 7 groups based on Astograph and S.P. instances criteria. Of 92 patients with positive test results, 91% met the set Astograph criterium; 72% met all three S.P. criteria, 1% one criterium and 12% failed to meet any of the S.P. criteria. It was noted that the patients met more the FEF50 and FEF25 criteria (87%) than FEV1 (73%). Also, there was no significant increase in respiratory resistance for those with a predominant reaction in small airways (9%). This fact points to the need of introducing appropriate complementary Astograph methods.