A DEVICE FOR OVERCOMING DISCOORDINATION WITH METERED-DOSE INHALERS

Background: Despite widespread acceptance of metered-dose inhalers (MD Is) in the treatment of asthma, many patients fail to operate these de vices correctly. Inability to properly coordinate activation with onse t of inhalation is regarded as the major factor in suboptimal MDI ther apy. Methods: We evaluated Autohaler Inhalation Device (3M Pharmaceuti cals, St. Paul, Minn.), a breath-activated MDI that is typically activ ated at a triggering flow rate of approximately 0.5 L/sec. We compared bronchodilator effect of pirbuterol acetate (Maxair), inhaled from Au tohaler and a standard MDI, under conditions that ensured optimal tech nique in 20 patients with asthma. Spirometric variables (forced expira tory volume in 1 second [FEV1], forced expiratory flow between 25% and 75% of vital capacity [FEF25-75], forced vital capacity [FVC]) were m easured before and at 15, 30, 60, and 90 minutes after two inhalations of full inspiratory reserve volume for each device. Results: Both dev ices produced significant and similar bronchodilation. Mean FEV1 incre ased 32% above baseline 60 minutes after use of Autohaler and 31% afte r use of a standard MDI. Similar changes were noted in FEF25-75 and FV C for the two devices. Differences between devices for all spirometric variables were not statistically significant. Conclusion: Autohaler p rovides a promising alternative to the standard MDI by overcoming brea th-hand discoordination.