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Wigginton KR, Arts PJ, Clack HL, Fitzsimmons WJ, Gamba M, Harrison KR, LeBar W, Lauring AS, Li L, Roberts WW, Rockey NC, Torreblanca J, Young C, Anderegg LG, Cohn AM, Doyle JM, Meisenhelder CM, Raskin L, Love NG, Kaye KS. Validation of N95 Filtering Facepiece Respirator Decontamination Methods Available at a Large University Hospital. Open Forum Infect Dis 2021; 8:ofaa610. [PMID: 33575418 PMCID: PMC7863868 DOI: 10.1093/ofid/ofaa610] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Due to unprecedented shortages in N95 filtering facepiece respirators, healthcare systems have explored N95 reprocessing. No single, full-scale reprocessing publication has reported an evaluation including multiple viruses, bacteria, and fungi along with respirator filtration and fit. METHODS We explored reprocessing methods using new 3M 1860 N95 respirators, including moist (50%-75% relative humidity [RH]) heat (80-82°C for 30 minutes), ethylene oxide (EtO), pulsed xenon UV-C (UV-PX), hydrogen peroxide gas plasma (HPGP), and hydrogen peroxide vapor (HPV). Respirator samples were analyzed using 4 viruses (MS2, phi6, influenza A virus [IAV], murine hepatitis virus [MHV)]), 3 bacteria (Escherichia coli, Staphylococcus aureus, Geobacillus stearothermophilus spores, and vegetative bacteria), and Aspergillus niger. Different application media were tested. Decontaminated respirators were evaluated for filtration integrity and fit. RESULTS Heat with moderate RH most effectively inactivated virus, resulting in reductions of >6.6-log10 MS2, >6.7-log10 Phi6, >2.7-log10 MHV, and >3.9-log10 IAV and prokaryotes, except for G stearothermohphilus. Hydrogen peroxide vapor was moderately effective at inactivating tested viruses, resulting in 1.5- to >4-log10 observable inactivation. Staphylococcus aureus inactivation by HPV was limited. Filtration efficiency and proper fit were maintained after 5 cycles of heat with moderate RH and HPV. Although it was effective at decontamination, HPGP resulted in decreased filtration efficiency, and EtO treatment raised toxicity concerns. Observed virus inactivation varied depending upon the application media used. CONCLUSIONS Both moist heat and HPV are scalable N95 reprocessing options because they achieve high levels of biological indicator inactivation while maintaining respirator fit and integrity.
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Affiliation(s)
- Krista R Wigginton
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter J Arts
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Herek L Clack
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William J Fitzsimmons
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Mirko Gamba
- Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Katherine R Harrison
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William LeBar
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Adam S Lauring
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Lucinda Li
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - William W Roberts
- Department of Urology, University of Michigan Health System, Ann Arbor, Michigan, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicole C Rockey
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Jania Torreblanca
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Carol Young
- Department of Pathology, Clinical Microbiology, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Loïc G Anderegg
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts, USA
| | - Amy M Cohn
- Department of Industrial & Operations Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts, USA
| | | | - Lutgarde Raskin
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Nancy G Love
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Keith S Kaye
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
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Steinberg BE, Aoyama K, McVey M, Levin D, Siddiqui A, Munshey F, Goldenberg NM, Faraoni D, Maynes JT. Efficacy and safety of decontamination for N95 respirator reuse: a systematic literature search and narrative synthesis. Can J Anaesth 2020; 67:1814-1823. [PMID: 32720256 PMCID: PMC7384726 DOI: 10.1007/s12630-020-01770-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 01/24/2023] Open
Abstract
PURPOSE Under times of supply chain stress, the availability of some medical equipment and supplies may become limited. The current pandemic involving severe acute respiratory syndrome coronavirus 2 has highlighted limitations to the ordinary provision of personal protective equipment (PPE). For perioperative healthcare workers, N95 masks provide a stark example of PPE in short supply necessitating the creation of scientifically valid protocols for their decontamination and reuse. METHODS We performed a systematic literature search of MEDLINE, Embase, Cochrane CENTRAL databases, and ClinicalTrials.gov to identify peer-reviewed articles related to N95 mask decontamination and subsequent testing for the integrity of mask filtration and facial seal. To expand this search, we additionally surveyed the official statements from key health agencies, organizations, and societies for relevant citations. RESULTS Our initial database search resulted in five articles that met inclusion criteria, with 26 articles added from the expanded search. Our search did not reveal any relevant randomized clinical trials or cohort studies. We found that moist mask heating (65-80°C at 50-85% relative humidity for 20-30 min) and vaporous hydrogen peroxide treatment were supported by the literature to provide consistent viral decontamination without compromising mask seal and filtration efficiency. Other investigated decontamination methods lacked comprehensive scientific evidence for all three of these key criteria. CONCLUSIONS N95 mask reprocessing using either moist heat or vaporous hydrogen peroxide is recommended to ensure healthcare worker safety.
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Affiliation(s)
- Benjamin E Steinberg
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
| | - Kazuyoshi Aoyama
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
| | - Mark McVey
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
| | - David Levin
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
| | - Asad Siddiqui
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
| | - Farrukh Munshey
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
| | - Neil M Goldenberg
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
| | - David Faraoni
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
| | - Jason T Maynes
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1X8, Canada.
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada.
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Wang Q, Golshahi L, Chen DR. Advanced testing method to evaluate the performance of respirator filter media. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2016; 13:750-758. [PMID: 27104915 DOI: 10.1080/15459624.2016.1177647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Filter media for respirator applications are typically exposed to the cyclic flow condition, which is different from the constant flow condition adopted in filter testing standards. To understand the real performance of respirator filter media in the field it is required to investigate the penetration of particles through respirator filters under cyclic flow conditions representing breathing flow patterns of human beings. This article reports a new testing method for studying the individual effect of breathing frequency (BF) and peak inhalation flow rate (PIFR) on the particle penetration through respirator filter media. The new method includes the use of DMA (Differential Mobility Analyzer)-classified particles having the most penetrating particle size, MPPS (at the constant flowrate of equivalent mean inhalation flow rate, MIFR) as test aerosol. Two condensation particle counters (CPCs) are applied to measure the particle concentrations at the upstream and downstream of test filter media at the same time. Given the 10 Hz sampling time of CPCs, close-to-instantaneous particle penetration could be measured. A pilot study was performed to demonstrate the new testing method. It is found that the effect of BF on the particle penetration of test respirator filter media is of importance at all the tested peak inhalation flow rates (PIFRs), which is different from those reported in the previous work.
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Affiliation(s)
- Qiang Wang
- a Department of Mechanical and Nuclear Engineering , Virginia Commonwealth University , Richmond , Virginia
| | - Laleh Golshahi
- a Department of Mechanical and Nuclear Engineering , Virginia Commonwealth University , Richmond , Virginia
| | - Da-Ren Chen
- a Department of Mechanical and Nuclear Engineering , Virginia Commonwealth University , Richmond , Virginia
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