Skip to main content

Efficacy of noninvasive ventilation in patients with COVID-19

A Comment to this article was published on 22 December 2022

The Original Article was published on 22 July 2022

To the Editor,

In a recent study, Dr. Polok et al. [1] investigated the potential efficacy of noninvasive ventilation (NIV) in COVID-19 patients aged ≥ 70 years. They reported that primary NIV failure occurred in 74.7% (470/629) of these patients, and compared to primary invasive mechanical ventilation (IMV), primary NIV was significantly associated with increased mortality. This study adds great information to the current knowledge. However, several points should be noted when interpreting these findings.

NIV has been wildly used in COVID-19 patients. However, the efficacy varied greatly within different areas and COVID-19 periods. In the current study, the NIV failure rate is as high as 74.7%. Noteworthy, patients included in this study were recruited between March 2020 and April 2021, during which the medical resource was extremely limited (early stage of the COVID-19 break). During that period, the shortage of intensive care unit (ICU) beds required many COVID-19 patients to be treated outside the ICU despite severe gas exchange impairment, and NIV may be used as a surrogate of IMV. In this case, NIV use may delay necessary intubation and lung protective ventilation in patients with severe hypoxemia, and increase the risk of aspiration pneumonia [2].

Coppadoro et al. [3] compared the NIV efficacy between patients receiving full treatment support and those with limited medical care resources. A total of 306 patients were included, and the NIV failure rate in patients with limited medical care resources was similar to the current study (72% vs. 74%), and significantly higher than those with full treatment support (93/130 (72%) vs. 54/176 (31%), p < 0.001). In addition, another multicenter, randomized trial [4] performed at the late stage of COVID-19 (February 2021–November 2021, low risk of medical resource shortage) reported that 47% (75/159) of patients in the NIV group received endotracheal intubation, and the 28-day mortality was only 27%. Therefore, it is reasonable to infer that the high NIV failure rate in the current study may be caused by potential medical resource shortages and inappropriate application of NIV. Whether NIV can improve prognosis (timing and protocol) without medical resource shortage in COVID-19 needs further investigation [5].

Second, we also have some different opinions on the comparison between primary IMV and NIV. In the sensitivity analysis, we note that compared to primary IMV, NIV increased the mortality rate in patients with life-sustaining limitations (withheld or withdrawn). Withheld or withdrawn from life-sustaining usually represents a severe clinical condition (e.g., severe hypoxemia), in which NIV may be inappropriate. However, in patients without life-sustaining limitations, NIV and IMV showed similar mortality rates. Therefore, whether primary NIV was associated with worse outcomes than primary IMV remains uncertain.

Availability of data and materials

Not applicable.


  1. Polok K, Fronczek J, Artigas A, Flaatten H, Guidet B, De Lange DW, Fjolner J, Leaver S, Beil M, Sviri S, et al. Noninvasive ventilation in COVID-19 patients aged >/= 70 years-a prospective multicentre cohort study. Crit Care. 2022;26(1):224.

    Article  Google Scholar 

  2. Bellani G, Laffey JG, Pham T, Madotto F, Fan E, Brochard L, Esteban A, Gattinoni L, Bumbasirevic V, Piquilloud L, et al. Noninvasive ventilation of patients with acute respiratory distress syndrome: insights from the LUNG SAFE study. Am J Respir Crit Care Med. 2017;195(1):67–77.

    Article  Google Scholar 

  3. Coppadoro A, Benini A, Fruscio R, Verga L, Mazzola P, Bellelli G, Carbone M, Mulinacci G, Soria A, Noe B, et al. Helmet CPAP to treat hypoxic pneumonia outside the ICU: an observational study during the COVID-19 outbreak. Crit Care. 2021;25(1):80.

    Article  Google Scholar 

  4. Arabi YM, Aldekhyl S, Al Qahtani S, Al-Dorzi HM, Abdukahil SA, Al Harbi MK, Al Qasim E, Kharaba A, Albrahim T, Alshahrani MS, et al. Effect of helmet noninvasive ventilation vs usual respiratory support on mortality among patients with acute hypoxemic respiratory failure due to COVID-19: the HELMET-COVID randomized clinical trial. JAMA. 2022;328(11):1063–72.

    Article  CAS  Google Scholar 

  5. Ferreyro BL, Angriman F, Munshi L, Del Sorbo L, Ferguson ND, Rochwerg B, Ryu MJ, Saskin R, Wunsch H, da Costa BR, et al. Association of noninvasive oxygenation strategies with all-cause mortality in adults with acute hypoxemic respiratory failure: a systematic review and meta-analysis. JAMA. 2020;324(1):57–67.

    Article  CAS  Google Scholar 

Download references


Not applicable.



Author information

Authors and Affiliations



YS contributed to conception of the letter; YS and JS contributed to writing of the letter. Both authors read and approved the final manuscript.

Corresponding author

Correspondence to Yanfei Shen.

Ethics declarations

Ethics approval and consent to participate

Not applicable.

Competing interests


Consent for publication

Not applicable.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Shen, Y., Shao, J. Efficacy of noninvasive ventilation in patients with COVID-19. Crit Care 26, 368 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: