Covid-19 respiratory protection: the filtration efficiency assessment of decontaminated FFP2 masks responding to associated shortages

  1. M. Benboubker
  2. B. Oumokhtar
  3. F. Hmami
  4. K. El Mabrouk
  5. L.EL Alami
  6. B. Arhoune
  7. M F. Belahsen
  8. A. Aboutajeddine

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Abstract

During the Covid-19 pandemic, healthcare workers were extremely vulnerable to infection with the virus and needed continuous protection. One of the most effective and widely used means of protection was the FFP2 respirator. Unfortunately, this crisis created a shortage of these masks, prompting hospitals to explore opportunities to reuse them after decontamination.

An approach for assessing the filtration efficiency of decontaminated FFP2 masks has been proposed and applied to evaluate the possibilities of their safe reuse. The decontamination processes adopted are those based on moist heat or hydrogen peroxide. The approach introduces efficiency measures that define the filtration and protection capacity of the masks, which characterize both chemical and structural changes, and encompasses many techniques including scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The test protocol was applied to mask samples that had endured different decontamination cycles and the results of their efficiency measures were compared to brand-new masks’ performances.

The main result was that chemical and structural characterization of the decontaminated masks have shown no substantial change or deformation of their filter media structures. Indeed, the respiratory resistance test has shown that the results of both the FFP2 masks that have undergone a hydrogen peroxide disinfection cycle or a steam autoclave cycle remained constant with a small variation of 10 Pa from the EN149 standard. The chemical characterization, on the other hand, has shown that the filter media of the decontaminated masks remains unchanged, with no detectable chemical derivatives in its constituents.

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    SciScore for 10.1101/2021.01.18.21249976: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    The proposed reprocessing protocols for FFP2 masks or other respiratory protection still poses problems and technical difficulties related to both, logistical conditions and risk management limitations in the collection and reprocessing chain 28. Based on literature data and existing resources, two protocols for reprocessing FFP2 masks have been adopted in this study. One involves the use of hydrogen peroxide doped with silver ions and the other uses moist heat, described as a widely recognized technique in hospital Sterile Processing Systems 28. The undertaken work assessed the feasibility of the reprocessing and the reusing of FFP2 masks, for managing a possible shortage. The results obtained regarding the first reprocessing, based on hydrogen peroxide and silver ions, lead us to conclude that there was no influence on the performance of the tested masks. The characterization tests come to justify the chemical and structural stability of our samples. The presence of silver ions at low doses seemed negligible to cause an effect on the electrostatic filtration provided by the electric charge of the melt (“electret”) used in this type of masks. Another study using the same reprocessing method concluded that the mechanical integrity and performance of the FFP2 is maintained after exposure to 10 or 20 cycles of hydrogen peroxide 5. The concern of inactivation of Sars-CoV has been widely documented; indeed, there is a multitude of scientific research into the inactivation of viru...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  2. Version published to 10.1101/2021.01.18.21249976 on medRxiv