Extract
We read with interest the article by Li et al. [1] entitled “High-flow nasal cannula for COVID-19 patients: low risk of bio-aerosol dispersion”, recently published in the European Respiratory Journal. Although we do agree with the authors that high-flow nasal cannula (HFNC) might be an effective treatment for hypoxaemic coronavirus disease 2019 (COVID-19) patients, we believe that caution should be taken in considering HFNC in COVID-19 patients, as data about droplet dispersion and aerosol generation with HFNC are at least controversial [2]. The authors state that the scientific evidence of generation and dispersion of bio-aerosols via HFNC is similar to standard oxygen therapies. This statement is mainly based on the studies of Hui et al. [3] and Ip et al. [4], which showed that HFNC led to a smaller dispersion distance compared to non-rebreather and Venturi masks during exhaled smoke dispersion experiments. The assumption that the physical extent of exhaled air plumes is equal to the visible extent of exhaled smoke plumes is wrong: the visibility of smoke rapidly decreases when it mixes with clean air, but smoke particles do not disappear. In addition to that, the dispersion of small-sized smoke particles and aerosols is not identical to the dispersion of particles that have a broad range of sizes. These observations are important when studying the actual spread of viruses.
Abstract
HFNC seems to increase droplet spread, so caution should be taken if it is applied for COVID-19, and adequate protective measures should be provided. Further research on viral spread and risks associated with HFNC therapy in COVID-19 patients is needed. https://bit.ly/3gQjjrY
Footnotes
Conflict of interest: J. Elshof reports grants from Vivisol BV and Fisher and Paykel Ltd, outside the submitted work.
Conflict of interest: R.H.J. Hebbink reports grants and non-financial support from Fisher and Paykel Healthcare, outside the submitted work.
Conflict of interest: M.L. Duiverman reports grants from Philips BV, Vivisol BV, and Fisher and Paykel Ltd, and grants and personal fees from Resmed Ltd, outside the submitted work.
Conflict of interest: R. Hagmeijer has nothing to disclose.
- Received August 2, 2020.
- Accepted August 5, 2020.
- Copyright ©ERS 2020
This version is distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0.