Aerosol Generation during Peak Flow Testing: Clinical Implications during the COVID-19 Pandemic

ABSTRACT

Background: Peak flow testing is a common procedure performed in ambulatory care. There are currently no data regarding aerosol generation during this procedure. We measured small particle concentrations generated during peak flow testing. Several peak flow devices were compared to assess for differences in aerosol generation. The amount of aerosol generation should objectively inform infection control and mitigation strategies during the COVID-19 pandemic. Methods: Five healthy volunteers performed peak flow maneuvers in a particle free laboratory space. Two devices continuously sampled the ambient air during the procedure. One device can detect ultrafine particles from 0.02 - 1 micron, while the second device can detect particles of size 0.3, 0.5, 1.0, 2.0, 5.0, and 10 microns. Five different peak flow meters were compared to ambient baseline during masked and unmasked tidal breathing. Results: Ultrafine particles (0.02 - 1 micron) were generated during peak flow rate measurement. Ultrafine particle mean concentration was lowest with Respironics peak flow meter (1.25±0.47 particles/cc) and similar between Philips (3.06±1.22), Clement Clarke (3.55±1.22 particles/cc), Respironics low range (3.50±1.52 particles/cc), and Monaghan (3.78±1.31 particles/cc) peak flow meters. Although ultrafine particle mean concentration increased during peak flow measurements compared ambient baseline during masked (0.22±0.29 particles/cc) and unmasked (0.15±0.18 particles/cc) tidal breathing, these differences were small and remained well below ambient PFT room particle concentrations (89.9±8.95 particles/cc). Conclusions: In this study, we were able to establish the feasibility of measuring small particle production after peak flow testing. Our study shows that ultrafine particles are generated during peak flow measurement. Although all peak flow meters demonstrated increased mean particle concentration, differences were small compared to the mean particle concentrations found in the ambient clinical environment. Outpatient practices should be aware of the potential risk of these findings and take appropriate infection control precautions.