Efficacy of the PARI Filter/Valve set to prevent environmental contamination with aerosol during nebulizer therapy


Uwe Schuschnig, Rosina Ledermüller & Jens Gramann

PARI GmbH, Lochhamer Schlag 21, Gräfelfing, Germany



During aerosol therapy with a PARI jet nebulizer, about two thirds of the aerosolized drug are inhaled while one third is emitted to the environment during exhalation. In order to avoid environmental contamination with aerosols, PARI is marketing a filter set to capture the exhaled fraction.

The purpose of this study was to test the efficacy of the filter system and to determine the aerosol amounts emitted to the environment during nebulizer therapy with PARI nebulizers.



LC PLUS and LC SPRINT nebulizers were tested (n=6, each) in breath simulation experiments using an adult breathing pattern. In addition to inspiratory and expiratory filters, nebulizer was placed under an extraction hood with a third particle filter to capture the aerosol emitted through leakages or at the inhalation valve. In order to validate the experiments, mass recovery rate was also determined.



With the PARI filter set attached to the nebulizers, the aerosol amounts emitted to the environment are below 1% of the total aerosolized drug amount. The mean values ranged from 0.4% for the LC PLUS to 0.6% for the LC SPRINT. The highest value found in a single experiment was 0.82%. The mean recovery rate in the experiments was 99.7%.

In absolute amounts, of 2.5 ml liquid initially filled into the nebulizer, 0.006 ml liquid was emitted to the environment instead of 0.36 ml without expiratory filter. This corresponds to a 98.4% reduction of aerosol contamination by the expiratory filter set.