RESUMO
BACKGROUND: In vivo deposition studies of aerosol administration during noninvasive ventilation (NIV) are scarce in the literature. The aim of this study was to compare radioaerosol pulmonary index and radioaerosol mass balance in the different compartments (pulmonary and extrapulmonary) of radio-tagged aerosol administered using vibrating mesh nebulizers and conventional jet nebulizers during NIV. METHODS: This was a crossover clinical trial involving 10 healthy subjects (mean age of 33.7 ± 10.0 y) randomly assigned to both treatment arms of this study: group 1 (NIV + vibrating mesh nebulizer, n = 10) and group 2 (NIV + jet nebulizer, n = 10). All subjects inhaled 3 mL of technetium-99m diethylenetriaminepentaacetic acid (25 mCi) and 0.9% saline solution via vibrating mesh and jet nebulizers during NIV through a face mask secured with straps while receiving positive inspiratory and expiratory pressures of 12 and 5 cm H2O, respectively. Scintigraphy was performed to count radioaerosol particles deposited in the regions of interest to determine radioaerosol mass balance from the lungs, upper airways, stomach, nebulizer, ventilator circuit, inspiratory and expiratory filters, and mask as a percentage. RESULTS: Vibrating mesh nebulizers deposited 972,013 ± 214,459 counts versus jet nebulizer with 386,025 ± 130,363 counts (P = .005). In a determination of mass balance, vibrating mesh nebulizers showed a higher deposition of inhaled radioaerosol compared with jet nebulizers (23.1 ± 5.8% vs 6.1 ± 2.5%, P = .005) and a higher proportion of radioaerosol deposited into the lungs (5.5 ± 0.9% versus 1.5 ± 0.6%, respectively, P = .005). The residual drug volume was lower with vibrating mesh nebulizers (5.1 ± 1.5%) compared with jet nebulizers (41.3 ± 4.2%, P = .005). CONCLUSIONS: During NIV in healthy subjects, vibrating mesh nebulizers delivered > 2-fold more radiolabeled drug into the respiratory tract compared with conventional jet nebulizers. Additional studies are recommended in subjects with asthma, COPD, bronchiectasis, and cystic fibrosis to better understand differences in both aerosol delivery and response. (ClinicalTrials.gov registration NCT01889524.).