Placing a Mask on COVID-19 Patients during High-Flow Nasal Cannula Therapy Reduces Aerosol Particle Dispersion

High-flow nasal cannula (HFNC) has been shown to improve oxygenation and reduce the need for intubation for hypoxemic patients [1]. A retrospective study reported the effectiveness of HFNC to improve oxygenation of COVID-19 patients [2]. The transmission route of the SARS-CoV-2 virus remains controversial [3, and concerns persist of potentially increased virus transmission when utilising HFNC among COVID-19 patients [3–5]. Computational fluid dynamic simulations reported that wearing a surgical/procedure mask over HFNC may reduce aerosol droplet dispersion [6]. Footnotes This manuscript has recently been accepted for publication in the ERJ Open Research . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJOR online. Please open or download the PDF to view this article. Conflict of interest: J. Li reports unrestricted funding from Fisher & Paykel Healthcare during the conduct of the study. Conflict of interest: Dr. Fink is CSO for Aerogen Pharma Corp, developing drug device products for the critical care setting. Conflict of interest: Dr. Elshafei has nothing to disclose. Conflict of interest: Ms. Stewart has nothing to disclose. Conflict of interest: Dr. Barbian has nothing to disclose. Conflict of interest: Dr. Mirza has nothing to disclose. Conflict of interest: Dr. Al-Harthi has nothing to disclose. Conflict of interest: D. Vines reports consultancy fees from Ohio Medical and grants from Teleflex Medical outside the submitted work. Conflict of interest: Dr. Ehrmann reports grants, personal fees and non-financial support from Fisher and Paykel healthcare, grants from Hamilton medical, during the conduct of the study; grants, personal fees and non-financial support from Aerogen Ltd, personal fees and non-financial support from La Diffusion Technique Francaise, outside the submitted work;.