Sent: Sunday, April 5, 2020 6:00:08 PM
Subject: ACEOM's Webinar summary: Protecting Health Care Workers-Reuse and Decontamination of N95 Respirators
Webinar description:COVID-19: Protecting Health Care Workers ‰?? Reuse and Decontamination of N95 Respirators.
Speakers include: David Rempel, MD, FACOEM, UCSF; Marie de Perio, MD, NIOSH; Edward Fisher, MS, NIOSH, CDC; Margaret Gardel, PhD, N95DECON consortium, U. Chicago; Mathew Stiegel, PhD & Antony Schwartz, Duke U. and Duke Health; Shawn G. Gibbs, PhD, MBA, CIH, Indiana U.
Executive summary:
CDC and NIOSH speakers discussed recent guidance for crises capacity strategies to optimize supplies during this national emergency of the COVID-19 pandemic. Specifically, they reviewed the need for decontamination and reuse of N95 respirators in healthcare settings when there are limited supplies. An overview of the decontamination and reuse technologies was also provided. The CDC speaker noted that an update to its February 2020 guidance on this topic will be released late on 4/3/20.
Health care and university speakers reviewed facility-specific validation of two decontamination methods for the reuse of N95 respirators. U. Nebraska tested and confirmed the use of UV germicidal irradiation (UVGI) at their site and Duke Health performed test runs to validate Battelle‰??s vaporized hydrogen peroxide (VHP) decontamination process in Duke‰??s facility. The N95DECON consortium proposed a third and promising method of using moist heat for decontaminating N95 respirators. This method is being evaluated for its potential efficacy.
Additional information is available at:
https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html
The Battelle Report is available at: https://www.fda.gov/media/136386/download
CDC/NIOSH Overview:
CDC identified VHP, UVGI, and moist heat as promising N95 decontamination methods.
Hospitals, healthcare systems, researchers, and decontamination companies should focus their efforts on these three technologies.
On March 29, 2020, the FDA cleared the first decontamination system for reprocessing N95s. Specifically, Battelle‰??s VHP method was approved by the FDA Emergency Use Authorization.
‰?¢ VHP inactivated SARS-COV-2 on N95 without harming filtration and fit. No residual chemical hazard was present.
‰?¢ N95s were decontaminated up to 20 times without degrading their performance (i.e. filter, straps or fit of 3M N95 respirators). This is unknown for other models of N95s.
‰?¢ Fit of the N95 respirator was shown to be unaffected for up to 20 VHP cycles using a head form.
*For more details on VHP, please refer to the webinar summary issued on April 1, 2020: ‰??Duke Health clinicians and researchers have confirmed a method to decontaminate N95 masks using hydrogen peroxide vaporization and described the overall process‰??.
CDC‰??s general crisis capacity guidance is provided below on:
Use of N95s beyond the manufacturer-designated shelf life for healthcare delivery.
Use of N95s evaluated and complying with standards used in other countries.
Perform initial fit tests for N95 respirators. Wearers must perform seal checks with each donning of new and reused N95 respirators.
Use of UVGI, VHP, and moist heat voids NIOSH approval.
Decontamination methods need to reduce the pathogen burden, maintain the function of the N95, and present no residual chemical hazard.
Decontamination technologies should be used cautiously. Only trained professional staff should operate decontamination equipment.
Additional info is available at: https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html
U. Nebraska‰??s Ultraviolet germicidal irraditation (UVGI):
U. Nebraska chose UVGI because of their experience and familiarity with this technology when treating Ebola patients in 2015. Therefore, this UVGI facility was in place and available for immediate use for COVID-19 last resort N95 decontamination procedures.
Qualitative fit tests were conducted on five N95 respirators. They all maintained filtration efficiency and fit. Due to a severe shortage of N95 respirators, quantitative fit tests could not be performed. Therefore, the number of UVGI cycles an N95 can undergo without degradation is unknown.
Filtration and structural integrity for five N95 respirators were maintained after decontamination.
A dose of 1-2 j/cm2 of UVGI inactivated 99.90 to 99.99% of influenza (H1H1, H5N1, H7N9), MERS-CoV, and SARS-CoV on N95 material.
For the confirmation process, BSL2 bacterial and viral surrogates were used to seed the N95 surface to define the UV dosage in the room (i.e. Staphylococcus aureus and Chikungunya virus). Ten N95 respirators were exposed to UVGI and tested for organism kill of 1 million at each round.
Both surfaces of the N95 respirator material were irradiated. The N95 respirator was not penetrated by the UV irradiation.
Antiviral and antimicrobial N95 surface testing confirmed effective decontamination.
Careful placement of N95 respirators in the room was needed to ensure proper UV irradiation doses.
UVGI doses can be difficult to fine-tune.
UVGI was measured in the room with a UV meter for exposure times and dosage consistency.
They optimized the process by painting the room with UV reflective paint to enhance the dosage delivered to the N95s.
Training and understanding of the UVGI process was emphasized to gain the trust of the health care personnel.
Individual N95 assignment to each wearer was implemented to ensure the same wearer reused their decontaminated N95 respirator.
Additional info is available at: https://www.nebraskamed.com/covid
Moist Heat:
A thermal cycle of 60-85 degrees Celcius (140-185 F) with 50-85% relative humidity for 30 minutes is a promising method for inactivation of coronaviruses in solution and on N95 respirators, respectively.
Commonly available devices in hospitals can maintain 140-167 F (i.e. warming cabinets, some autoclaves, bacterial incubators, etc.).
Separate N95 respirators and return to assigned wearer to reduce risk of cross contamination.
CDC released guidance on heat & humidity for N95 respirator decontamination on March 31, 2020.
This method has not been validated in an FDA-approved process.
*Notes of interest:
CDC and NIOSH are starting to see counterfeit and knock-off N95 respirators.
N95 respirator straps tend to break after 18 ‰?? 30 hours of usage without being decontaminated for reuse.
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