A mesh nebulizer is more effective than jet nebulizer to nebulize bronchodilators during non-invasive ventilation of subjects with COPD: A randomized controlled trial with radiolabeled aerosols

Background: Beneficial effects from non-invasive ventilation (NIV) in acute COPD are well-established, but the impact of nebulization during NIV has not been well described. Aim: To compare pulmonary deposition and distribution across regions of interest with administration of radiolabeled aerosols generated by vibrating mesh nebulizers (VMN) and jet nebulizer (JN) during NIV. Methods: A crossover single dose study involving 9 stable subjects with moderate to severe COPD randomly allocated to receive aerosol administration by the VMN Aerogen and the MistyNeb jet nebulizer operating with oxygen at 8 lpm during NIV. Radiolabeled bronchodilators (fill volume of 3 mL: 0.5 mL salbutamol 2.5 mg + 0.125 mL ipratropium 0.25 mg and physiologic saline up to 3 mL) were delivered until sputtering during NIV (pressures of 12 cmH2O and 5 cmH2O - inspiratory and expiratory, respectively) using an oro-nasal facemask. Radioactivity counts were performed using a gamma camera and regions of interest (ROIs) were delimited. Aerosol mass balance based on counts from the lungs, upper airways, stomach, nebulizer, circuit, inspiratory and expiratory filters, and mask were determined and expressed as a percentage of the total. Results: Both inhaled and lung doses were greater with VMN (22.78 +/- 3.38% and 12.05 +/- 2.96%, respectively) than JN (12.51 +/- 6.31% and 3.14 +/- 1.71%; p=0.008). Residual drug volume was lower in VMN than in JN (3.08 +/- 1.3% versus 46.44 +/- 5.83%, p=0.001). Peripheral deposition of radioaerosol was significantly lower with JN than VMN. Conclusions: VMN deposited > 3 fold more radioaerosol into the lungs of moderate to severe COPD patients than JN during NIV.