Dry heat sterilization as a method to recycle N95 respirator masks: The importance of fit

Abstract

In times of crisis, including the current COVID-19 pandemic, the supply chain of filtering facepiece respirators, such as N95 respirators, are disrupted. To combat shortages of N95 respirators, many institutions were forced to decontaminate and reuse respirators. While several reports have evaluated the impact on filtration as a measurement of preservation of respirator function after decontamination, the equally important fact of maintaining proper fit to the users’ face has been understudied. In the current study, we demonstrate the complete inactivation of SARS-CoV-2 and preservation of fit test performance of N95 respirators following treatment with dry heat. We apply scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD) measurements, Raman spectroscopy, and contact angle measurements to analyze filter material changes as a consequence of different decontamination treatments. We further compared the integrity of the respirator after autoclaving versus dry heat treatment via quantitative fit testing and found that autoclaving, but not dry heat, causes the fit of the respirator onto the users face to fail, thereby rendering the decontaminated respirator unusable. Our findings highlight the importance to account for both efficacy of disinfection and mask fit when reprocessing respirators to for clinical redeployment.

Brief Cost Analysis of Surgical Personal Protective Equipment During the COVID-19 Pandemic

“… 19 Although the availability of N95s has increased significantly over the course of the pandemic, prices have also increased and uncertainty remains in how the COVID-19 pandemic will continue to evolve. Nevertheless, studies have increasingly suggested that N95s can be decontaminated and reused 20 , 21 ; taken together with our findings implies that healthcare systems could prioritize reuse, particularly for OR procedures.…”

Colônias de bactérias encontradas em máscaras N95 reutilizadas e descontaminadas pelo calor

“…Embora a autoclavagem (ou seja, vapor a ~121°C e > 15 PSI) seja um método comprovado de esterilização da maioria dos patógenos, não é viável para descontaminação de respiradores N95 usados porque o calor úmido pode degradar a eficiência do filtro. No meio da cultura, SARS-CoV-2 foi relatado como inativado pelo tratamento de calor seco em apenas 5 minutos a 70°C e a exposição do SARS-Cov-2 em superfícies para o calor seco a > 70°C por >30 minutos é suficiente para alcançar uma redução de ≥ 3 log de títulos virais, atendendo às recomendações da Food and Drug Administration, ou Administração de Alimentos e Medicamentos (FDA) para FFR (Yuen et al, 2022).…”

“…Os respiradores autoclavados falharam no teste de ajuste do respirador e sugeriram que a mudança na eficiência da filtragem é de até 7,73%. No entanto, a análise do material respirador não corrobora mudanças significativas no material de filtragem que poderiam levar a essas reduções na eficiência da filtragem (Yuen et al, 2022).…”

Disposable Face-Mask Waste Management and Assessment Through Willingness to Pay and SWOT Framework in Post COVID-19 Pandemic

“…Previous research proposed a recycling technique for mask waste using ultraviolet radiation disinfectant and autoclaving [37,38]. This contradicts [39,40], which finds that disposable medical masks are difficult to recycle because they can potentially contain viruses and bacteria.…”