- Or: a documented increase in FEV1 of >12 % and > 150 mL within 2 hours following inhalation of 80 µg ipratopium bromide within 6 months of screening and an increase in FEV1 of > 6 % and > 100 mL within 2h following inhalation of 80 µg ipratopium bromide (Atrovent MDI via spacer) at the screening visit (in order to allow for potential fluctuations in the response to ipratropium bromide in patients known to be responders to ipratropium bromide)