Aerosol Deposition in Asthmatic Obese Women Using Heliox: A Randomized, Crossover, Controlled Clinical Trial Study

BACKGROUND: Obese asthmatics are difficult to treat effectively, worse asthma control, and do not respond as well to standard therapy as lean asthmatic. Medical aerosols an important route of drug delivery in asthma, but narrowing in the airway cause by the obesity, can provoke turbulence and the effectiveness of the treatment could be compromise.

AIM: To assess pulmonary deposition, distribution of radio-aerosol and analyze upper way dimension in obese and normal weight women, using 2-D planar scintigraphyand and computed tomography. METHODS: 20 obese women, 10 asthmatics and 10 non-asthmatics took part of the first part of the study. Anthropometric and clinical assessments were carried out, than lung function was performed. After randomization of the sequence of gas (sequence 1- oxygen and heliox; sequence 2-heliox and heliox) that would be used to inhale an aerosol with technetium labeled diethylenetriamine penteacetic acid (99mTc - DTPA) with an activity of 1 mCi in a total dose volume with normal saline of 2,5 ml using a vibrating mesh inhaler. All patients inhaled two times with one week of washout between then to eliminate risk of residual trace radiation and to avoid the possibility of bias.