Efficacy of Various Mitigation Devices in Reducing Fugitive Emissions from Nebulizers

Abstract

Introduction: 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.

Methods: 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 facemask for VMN, and a facemask 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 feet from participants measuring aerosol concentrations at sizes of 0.3-10 µm at baseline, before, during and after each treatment. The Ethics Committee at Rush University approved this study.

Results: Fugitive aerosol concentrations were higher with SVN than VMN and higher with a facemask 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<0.05). An Exhalo scavenger over the mask reduced 0.5-3.0 µm sized particle concentrations for SVN (all p<0.05) but not VMN. Vapotherm scavenger and filter facemask reduced fugitive aerosol concentrations regardless of the nebulizer type.

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