Summary: Background: The diagnosis of chronic obstructive pulmonary disease (COPD) is based on spirometry that requires a forced expiratory manoeuvre. which is laborious and difficult for mass screening. Impulse oscillometry (IOS) is easier than spirometry and performed with tidal breathing. We sought to develop an equation for predicting forced expiratory volume in 1 s (FEV1)/forced ... https://pipingrockers.shop/product-category/dl-phenylalanine/