Drug-induced changes in airways obstruction reflected by forced expiratory flows and airway resistance measured with...

14 patients with partially reversible airways obstruction were studied with forced expiratory flows (FEV1, PEFR) and with airway resistance measured by an oscillometric method (Siregnost FD-5) before and after drug-induced changes in airways obstruction. 10 inhaled methacholine to induce bronchoconstriction, and 4 inhaled salbutamol and an additional dose of neosynephrine to induce bronchodilation. Intraindividual changes in resistance (Rosc) measured by the oscillometer with quiet breathing showed a fair significant correlation with changes in FEV1 (r = 0.54, p less than 0.05) and changes in PEFR measured by the Wright peak flow meter (r = 0.59, p less than 0.05). The present type of oscillator can be used for provocations starting from normal airway resistance but not for measures of treatment effects in markedly obstructive patients.