Autoclave Sterilization and Ethanol Treatment of Re-used Surgical Masks and N95 Respirators during COVID-19: Impact on their Performance and Integrity

Link to article at PubMed

Grinshpun SA, et al. J Hosp Infect 2020.


BACKGROUND: An exceptionally high demand for surgical masks and N95 filtering facepiece respirators (FFRs) during the COVID-19 pandemic has considerably exceeded their supply. These disposable devices are generally not approved for routine decontamination and re-use as standard of care while this practice has widely occurred in hospitals. The US Centers for Disease Control and Prevention allowed it "as a crisis capacity strategy." However, limited testing was conducted on the impact of specific decontamination methods on the performance of N95 FFRs and no data was presented for surgical masks.

AIM: We evaluated common surgical masks and N95 respirators with respect to the changes in their performance and integrity resulting from autoclave sterilization and a 70% ethanol treatment; these methods are frequently utilized for re-used filtering facepieces in hospitals.

METHODS: The filter collection efficiency and pressure drop were determined for unused masks and N95 FFRs, and for those subjected to the treatments in a variety of ways. The collection efficiency was measured for particles of approximately 0.037-3.2 μm to represent aerosolized single viruses, their agglomerates, bacteria and larger particles carriers.

FINDINGS: The initial collection efficiency and the filter breathability may be compromised by sterilization in an autoclave and ethanol treatment. The effect depends on a protective device, particle size, breathing flow rate, type of treatment and other factors. Additionally, physical damages were observed in N95 respirators after autoclaving.

CONCLUSION: Strategies advocating decontamination and re-use of filtering facepieces in hospitals should be re-assessed considering the data obtained in this study.

PMID:32599011 | DOI:10.1016/j.jhin.2020.06.030

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