Crossover Evaluation of Compressors and Nebulizers Typically Used by Cystic Fibrosis Patients

Compressor/nebulizer units are used to deliver inhaled medications to patients with cystic fibrosis. Practitioners and parents frequently replace either the compressor or the nebulizer with a similar component from a different brand. We hypothesized that these changes could affect the compressor/nebulizer flow-pressure and aerosol characteristics. The following compressors were studied: Pari Vios, Pulmo-Aide model 5650D, and Inspiration Elite model HS456. The following nebulizers were studied: Pari LC Plus, Viox, and SideStream Plus. Units that underwent intense use were tested. The recommended compressor/nebulizer combinations by the manufacturers were compared to all other combinations. In-line measurements of maximal flow and pressure were done for all combinations. A Next Generation Impactor was used to determine particle-size characteristics of albuterol (2.5 mg/3 mL). A breathing simulator programmed to deliver an adult breathing pattern was used. Albuterol concentration was measured with spectrophotometry at 276 nm. The following variables were studied: maximal flow and pressure generated by the compressor/nebulizer, mass median aerodynamic diameter, percentage of drug mass contained in particles < 5 μm, and inhaled mass in the respirable range. Replacing the nebulizer resulted in changes in the flow-pressure characteristics, particle size, and inhaled mass in the respirable range of the paired compressor/nebulizers. The changes were more pronounced when the nebulizer was replaced than when the compressor was changed. Our findings indicate that, in general, replacing the nebulizer or compressor with a different brand changes the flow-pressure and aerosol characteristics. Practitioners should be cautious when changing compressor/nebulizer pairs unless they are aware of the resulting impact on the flow-pressure and aerosol characteristics.