Efficacy of Various Mitigation Devices in Reducing Fugitive Emissions from Nebulizers

Fugitive aerosol concentrations generated by different nebulizers and interfaces in vivo and mitigation of aerosol dispersion into the environment with various commercially available devices are not known.

Nine healthy volunteers were given 3 mL saline with a small-volume nebulizer (SVN) or vibrating mesh nebulizer (VMN) with a mouthpiece, a mouthpiece with an exhalation filter, an aerosol mask with open ports for SVN and a valved face mask for VMN, and a face mask with a scavenger (Exhalo) in random order. Five of the participants received treatments using a face tent scavenger (Vapotherm) and a mask with exhalation filter with SVN and VMN in a random order. Treatments were performed in an ICU room with 2 particle counters positioned 1 and 3 ft from participants measuring aerosol concentrations at sizes of 0.3-10.0 μm at baseline, before, during, and after each treatment.

Fugitive aerosol concentrations were higher with SVN than VMN and higher with a face mask than a mouthpiece. Adding an exhalation filter to a mouthpiece reduced aerosol concentrations of 0.3-1.0 μm in size for VMN and 0.3-3.0 μm for SVN (all P < .05). An Exhalo scavenger over the mask reduced 0.5-3.0 μm sized particle concentrations for SVN (all P < .05) but not VMN. Vapotherm scavenger and filter face mask reduced fugitive aerosol concentrations regardless of the nebulizer type.

SVN produced higher fugitive aerosol concentrations than VMN, whereas face masks generated higher aerosol concentrations than mouthpieces. Adding an exhalation filter to the mouthpiece or a scavenger to the face mask reduced aerosol concentrations for both SVN and VMN. Vapotherm scavenger and filter face mask reduced fugitive aerosols as effectively as a mouthpiece with an exhalation filter. This study provides guidance for reducing fugitive aerosol emissions from nebulizers in clinical practice.