In patients with obstructive lung disease like asthma aerosol therapy is the most used for drug administration. A order to make better use of aerosolized drugs in asthmatic patients, studies focus on ways to optimize this administration. Objective: To evaluate the efficacy of nebulized bronchodilators carried by heliox associated with positive expiratory pressure (PEP) in lung deposition of radiation activity in adult asthmatic patients between episodes and its impact on lung function. Methods: A randomized controlled trial involving 32 with a mean age of 47.28 ± 9.67 of which 25% of the sample are male, these patients were divided into four groups: heliox + PEP, + PEP oxygen, heliox and oxygen in Regarding the anthropometric characteristics, parameters and cardiopulmonary baseline spirometry data were similar for all groups. For inhalation lung scintigraphy was used a noninvasive delivery system - orofacial mask with two unidirectional valves nontoxic - inspiratory and expiratory branch - connected to the nebulizer for radioisotopes associated with PEP of 10 cm H2O. At the end of inhalation, the images were acquired in a scintillation camera at 0, 15, 30, 45 and 60 min. In order to analyze the aerosol deposition in different lung areas were delineated regions of interest (ROIs) in the vertical - the upper, middle and bottom - and horizontal central, intermediate and peripheral. Results: The spirometric data showed an increase in the values of forced expiratory volume in one second (FEV1) predicted when compared with the heliox group + PEP (80%, p = 0.030) with PEP + O2 (65%, p = 0.030). As for CI, there was also an increase in PEP + heliox group (0.05 L, p = 0.012) compared to groups without oxygen and heliox PEP (0.03 L, 0.03 L, p = 0.012 respectively) for the total number of counts, no differences were seen between groups with heliox and oxygen with PEP PEP (482510, 577598, p = 0.262 respectively) for the total number of counts by comparing the oxygen group + PEP (577,598) with the heliox group (332,951, p = 0.004) and oxygen without PEP (409,526, p = 0.045), there was a greater number of counts in the O2 + PEP group. By analyzing the rate of pulmonary deposition (IDP) in the vertical gradient, higher deposition in the middle third (p = 0.001) when compared to upper and lower in both groups. With regard to IDPs in the horizontal gradient, there was greater deposition in the intermediate region when compared to central and peripheral (p = 0.003, 0.001 respectively) in all groups. As the penetration rate, no significant differences between groups (p = 0.726). When considering the pulmonary clearance, decreased with the number of counts over time within groups (p <0.05) but no differences between them: heliox + PEP (20.67%), PEP + oxygen (13.50%), heliox (16.27%) and oxygen (16%) - (p> 0.05). Conclusion: Although no differences in the rate of penetration and clearance of pulmonary radiation activity between groups, we noted a higher number of counts in patients who underwent nebulization with oxygen associated with PEP and a functional improvement in patients who underwent nebulization with PEP as spirometric values and CI.

Inclusion Criteria:

• Patients with clinical diagnosis of persistent asthma
• FEV1 <60% predicted more than one year
• Reversibility of bronchial obstruction after administration of bronchodilators at least 10% in FEV1 on spirometry.

Exclusion Criteria:

• patients unable to understand or perform the spirometric maneuver or failed to keep in proper positioning to obtain the scintigraphic images
• History of smoking over the past three years associated with a consumption greater than 100 cigarettes per year or who had history of smoking increased 10 years
• pulmonary comorbidities such as COPD, bronchiectasis and tuberculosis sequelae
• Pregnancy and any contraindication to the use of PEP, such as active hemoptysis, sinusitis, surgery or facial trauma, oral or injury, epistaxis, esophageal surgery and nausea.