Objective: To evaluate the use of inhaler devices by patients with severe asthma treated via the Programa para o Controle da Asma e Rinite Alérgica na Bahia (ProAR, Bahia State Asthma and Allergic Rhinitis Control Program), recording the frequency of their errors in performing key steps and the relationship between such errors and the lack of asthma control. Methods: A cross-sectional study involving 467 patients enrolled in the ProAR in the city of Salvador, Brazil. The devices evaluated were metered dose inhalers (MDIs), with or without a spacer, and dry powder inhalers (DPIs; Pulvinal® or Aerolizer®). For the assessment of the inhalation technique, a checklist was used; the patients were asked to demonstrate the technique so that an interviewer could observe all of the steps performed. For the assessment of asthma control, we used the 6-item asthma control questionnaire. Results: Most of the patients showed appropriate inhalation techniques when using the devices. When using an MDI, few patients made mistakes in the key step of "coordinating activation and inhalation" (5.2% and 9.1% with and without the use of a spacer, respectively). During Pulvinal® use, 39% of the patients did not inhale quickly and deeply, compared with only 5.8% during Aerolizer® use. Of the patients that made use of Aerolizer® alone, 71.3% appropriately performed all of the essential steps, and their asthma was controlled. Conclusions: Most of the patients in this sample, all of whom had been submitted to periodic checks of their inhalation technique (as part of the program), used the devices appropriately. Proper inhalation technique is associated with asthma symptom control.

Keywords: Asthma; Administration, inhalation; Metered dose inhalers; Dry powdered inhalers.