Comparative analysis of N95 respirators fit testing with commercially available and in house reagent

Objective.Respiratory protection programs, including fit testing of respirators, have been inconsistently implemented; evidence of their long-term efficacy is lacking. We undertook a study to determine the short- and long-term efficacy of training for fit testing of N95 respirators in both untrained and trained healthcare workers (HCWs).Design.Prospective observational cohort study.Methods.A group of at-risk, consenting HCWs not previously fit-tested for a respirator were provided with a standard fit-test protocol. Participants were evaluated after each of 3 phases, and 3 and 14 months afterward. A second group of previously fit-tested nurses was studied to assess the impact of regular respirator use on performance.Results.Of 43 untrained fit-tested HCWs followed for 14 months, 19 (44.2%) passed the initial fit test without having any specific instruction on respirator donning technique. After the initial test, subsequent instruction led to a pass for another 13 (30.2%) of the 43 HCWs, using their original respirators. The remainder required trying other types of respirators to acheive a proper fit. At 3 and 14 months' follow-up, failure rates of 53.5% (23 of 43 HCWs) and 34.9% (15 of 43 HCWs), respectively, were observed. Pass rates of 87.5%-100.0% were observed among regular users.Conclusions.Without any instruction, nearly 50% of the HCWs achieved an adequate facial seal with the most commonly used N95 respirator. Formal fit testing does not predict future adequacy of fit, unless frequent, routine use is made of the respirator. The utility of fit testing among infrequent users of N95 respirators is questionable.

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New Method for Fit Testing N95 Respirators

Gastroenterology Nursing ◽

10.1097/00001610-199801000-00015 ◽

1998 ◽

Vol 21 (1) ◽

pp. 33

Author(s):

&NA;

Keyword(s):

New Method ◽

Fit Testing ◽

N95 Respirators

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Respiratory Protection by Respirators: The Predictive Value of User Seal Check for the Fit Determination in Healthcare Settings

Infection Control and Hospital Epidemiology ◽

10.1086/659151 ◽

2011 ◽

Vol 32 (4) ◽

pp. 402-403 ◽

Cited By ~ 5

Author(s):

Simon Ching Lam ◽

Joseph Kok Long Lee ◽

Linda Yin King Lee ◽

Ka Fai Wong ◽

Cathy Nga Yan Lee

Keyword(s):

Electronic Device ◽

World Health ◽

Respiratory Pathogens ◽

Respiratory Protection ◽

Healthcare Settings ◽

The World ◽

Fit Testing ◽

Control And Prevention ◽

Health Organization ◽

N95 Respirators

The N95 respirator is one type that is recommended by the World Health Organization and the Centers for Disease Control and Prevention (CDC) to prevent inhalation of droplets that may act to transmit respiratory pathogens. However, the reliability of this respirator to prevent transmission is dependent on how well it is fitted to the wearer. For ill-fitting respirators, the average penetration by ambient aerosol was found to be 33%, compared with 4% for well-fitting respirators. Such penetration or leakage may be caused by the gap between the respirator and the wearer's face. Therefore, formal fit testing should be carried out prior to the use of N95 respirators. Quantitative fit testing measures “the adequacy of respirator fit by numerically measuring the amount of leakage into the respirator” using an electronic device.

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Comparing the fit of N95, KN95, surgical, and cloth face masks and assessing the accuracy of fit checking

PLoS ONE ◽

10.1371/journal.pone.0245688 ◽

2021 ◽

Vol 16 (1) ◽

pp. e0245688

Author(s):

Eugenia O’Kelly ◽

Anmol Arora ◽

Sophia Pirog ◽

James Ward ◽

P. John Clarkson

Keyword(s):

Poor Correlation ◽

Protective Equipment ◽

Respiratory Protection ◽

Factor Scores ◽

Self Assessment ◽

Fit Testing ◽

Assessment Guidelines ◽

Facial Differences ◽

N95 Respirators

Introduction The COVID-19 pandemic has made well-fitting face masks a critical piece of protective equipment for healthcare workers and civilians. While the importance of wearing face masks has been acknowledged, there remains a lack of understanding about the role of good fit in rendering protective equipment useful. In addition, supply chain constraints have caused some organizations to abandon traditional quantitative or/and qualitative fit testing, and instead, have implemented subjective fit checking. Our study seeks to quantitatively evaluate the level of fit offered by various types of masks, and most importantly, assess the accuracy of implementing fit checks by comparing fit check results to quantitative fit testing results. Methods Seven participants first evaluated N95 and KN95 respirators by performing a fit check. Participants then underwent quantitative fit testing wearing five N95 respirators, a KN95 respirator, a surgical mask, and fabric masks. Results N95 respirators offered higher degrees of protection than the other categories of masks tested; however, it should be noted that most N95 respirators failed to fit the participants adequately. Fit check responses had poor correlation with quantitative fit factor scores. KN95, surgical, and fabric masks achieved low fit factor scores, with little protective difference recorded between respiratory protection options. In addition, small facial differences were observed to have a significant impact on quantitative fit. Conclusion Fit is critical to the level of protection offered by respirators. For an N95 respirator to provide the promised protection, it must fit the participant. Performing a fit check via NHS self-assessment guidelines was an unreliable way of determining fit.

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Dry Heat as a Decontamination Method for N95 Respirator Reuse

10.26434/chemrxiv.12290621.v2 ◽

2020 ◽

Author(s):

Chamteut Oh ◽

Elbashir Araud ◽

Joseph V. Puthussery ◽

Hezi Bai ◽

Gemma G. Clark ◽

...

Keyword(s):

Heat Treatment ◽

Healthcare Providers ◽

Transmissible Gastroenteritis Virus ◽

Viable Option ◽

Dry Heat ◽

Tulane Virus ◽

Fit Testing ◽

Transmissible Gastroenteritis ◽

Dry Heat Treatment ◽

N95 Respirators

<div> <div> <p>A pandemic such as COVID-19 can cause a sudden depletion in the worldwide supply of respirators, forcing healthcare providers to reuse them. In this study, we systematically evaluated dry heat treatment as a viable option for the safe decontamination of N95 respirators (1860, 3M) before its reuse. We found that the dry heat generated by an electric cooker (100°C, 5% relative humidity, 50 min) effectively inactivated Tulane virus (>5.2-log<sub>10</sub> reduction), rotavirus (>6.6-log<sub>10</sub> reduction), adenovirus (>4.0-log<sub>10</sub> reduction), and transmissible gastroenteritis virus (>4.7-log<sub>10</sub> reduction). The respirator integrity (determined based on the particle filtration efficiency and quantitative fit testing) was not compromised after 20 cycles of 50-min dry heat treatment. Based on these results, we propose dry heat decontamination generated by an electric cooker (e.g., rice cookers, instant pots, ovens) to be an effective and accessible decontamination method for the safe reuse of N95 respirators.<br></p> </div> </div>

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The "Double Eights Mask Brace" Improves the Fit and Protection and Protection of a Basic Surgical Mask Amidst Covid-19 Pandemic

10.1101/2020.05.18.20099325 ◽

2020 ◽

Author(s):

Daniel P Runde ◽

Karisa Harland ◽

Paul Van Heukelom ◽

Brett Faine ◽

Patrick OShaughnessy ◽

...

Keyword(s):

Primary Outcome ◽

Rubber Band ◽

Primary Outcome Measure ◽

Study Objective ◽

Fit Testing ◽

Margin Of Safety ◽

The Subject ◽

N95 Respirators ◽

The Impact ◽

Median Height

Study Objective: The COVID-19 pandemic has resulted in widespread shortages in personal protective equipment, including N95 respirators. While basic surgical facemasks are more commonly available, their efficacy is limited due primarily to their poor face seal. This pilot study examined the impact of a rubber band mask brace on a basic surgical mask, as determined by quantitative fit testing. Methods: Subjects wearing a basic surgical facemask and the rubber band mask brace underwent quantitative fit testing using machinery designed to certify N95 mask fit. Subjects were tested with the brace anchored behind their eyes, with a paperclip behind the head, and on the side knobs of their face shields. The primary outcome measure was whether the subject passed the quantitative fit test at or above the OSHA verified standard for N95 masks. Results: Subjects (n=11) were 54.5% female, with a median height of 70 inches (IQR 68-74), weight of 170 lbs (IQR 145-215) and BMI of 24.6 (IQR 22.2-27.2), and encompassing 5 distinct N95 mask fit types. We found that 45%, 100% and 100% of subjects passed the quantitative fit test when the brace was anchored behind the ears, with a paperclip and on a face shield respectively. Conclusion: Of the 11 subjects included in the analysis, across a range of body habitus and N95 mask fit types, all passed the quantitative fit test when the mask brace was anchored on either face shield or with a paperclip. This data suggests the brace would offer an improved margin of safety when worn with a basic surgical mask.

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The importance of fit testing in decontamination of N95 respirators: A cautionary note

Journal of the American Academy of Dermatology ◽

10.1016/j.jaad.2020.05.008 ◽

2020 ◽

Vol 83 (2) ◽

pp. 672-674 ◽

Cited By ~ 7

Author(s):

David Ozog ◽

Angela Parks-Miller ◽

Indermeet Kohli ◽

Alexis B. Lyons ◽

Shanthi Narla ◽

...

Keyword(s):

Cautionary Note ◽

Fit Testing ◽

N95 Respirators

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Training and Fit Testing of Health Care Personnel for Reusable Elastomeric Half-Mask Respirators Compared With Disposable N95 Respirators

JAMA ◽

10.1001/jama.2020.4806 ◽

2020 ◽

Cited By ~ 9

Author(s):

Lisa A. Pompeii ◽

Colleen S. Kraft ◽

Erik A. Brownsword ◽

Morgan A. Lane ◽

Elisa Benavides ◽

...

Keyword(s):

Health Care ◽

Health Care Personnel ◽

Fit Testing ◽

N95 Respirators

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Evaluation of N95 Respirator Ultraviolet Decontamination and Clinical Reuse with Quantitative Fit Testing

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2021.187 ◽

2021 ◽

pp. 1-10

Author(s):

Gregory K. Wanner ◽

Douglas Ader ◽

Richard Caplan ◽

Amit S. Padaki ◽

Debra Ravert ◽

...

Keyword(s):

Failure Rate ◽

Probability Of Failure ◽

Fit Testing ◽

The Mean ◽

N95 Respirators ◽

Test Failure

Abstract The supply of N95 respirators has been severely strained by COVID-19. We used quantitative fit-testing to evaluate sixteen participants and forty-five respirators through up to four rounds of ultraviolet decontamination and clinical reuse. The mean fit-test failure rate was 29.7% and probability of failure increased through N95 reuse.

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Evaluating N95 Respirator Filtration, Seal, Qualitative and Quantitative Fit with Vaporous Hydrogen Peroxide Reprocessing

Antimicrobial Stewardship & Healthcare Epidemiology ◽

10.1017/ash.2021.38 ◽

2021 ◽

Vol 1 (S1) ◽

pp. s21-s21

Author(s):

Christina Yen ◽

Preeti Mehrotra ◽

Dana Pepe ◽

Sharon Wright ◽

Patrick Gordon ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Filtration Rate ◽

Factor Score ◽

Significant Degree ◽

Fisher Exact Test ◽

Qualitative And Quantitative ◽

Significant Difference ◽

Fit Testing ◽

N95 Respirators ◽

Change In Mean

Background: The COVID-19 pandemic has created personal protective equipment (PPE) shortages, particularly of N95 respirators. Institutions have used decontamination strategies including vaporous hydrogen peroxide (VHP) to augment respirator supplies. VHP can be used to decontaminate nonporous surfaces without compromising material integrity. However, little is known about its impact on N95 respirator efficacy. We assessed whether repeated VHP reprocessing altered 4 key respirator efficacy qualities: quantitative fit, qualitative fit, seal check, and filtration rate. Methods: We conducted a prospective cohort study from June 15 to August 31, 2020. In total, 7 participants were fitted to a 3M 1860 small or regular N95 respirator based on qualitative and quantitative fit testing. Respirators underwent 25 disinfection cycles with the Bioquell BQ-50 VHP generator. After each cycle, participants donned and doffed respirators and performed a seal check. Participants were given 2 attempts to pass their seal check. Every 10 cycles, qualitative fit testing was done using an aerosolized Bitrex solution. Quantitative fit testing was conducted using a PortaCount Pro 8038 Fit Tester to generate a fit factor score. Appropriate fit is defined as a fit factor score of 100 or greater. Quantitative testing was done at cycles 1, 3, 5, 7, 10, 15, 20, and 25. Filtration efficiencies of particles ≥0.3 µm in diameter were measured using the TSI Optical Particle Sizer 3330 at cycles 1, 5, 10, 15, 20, and 25. The Fisher exact test was used to assess qualitative fit and seal check. The Kruskal-Wallis test was used to analyze quantitative fit and filtration rate. Results: We observed no seal-check or quantitative-fit test failures during the study window. All participants passed qualitative fit testing. Although there was a significant degree of variability in fit factor scores across disinfection cycles (mean score 163.5, p <0.05), there was no significant difference between participants (p = 0.6) (Figure 1). There was no statistically significant change in mean filtration rate from cycle 10 to 25 (P = .05), and the filtration rate remained >95% by cycle 25 (Figure 2). Conclusions: VHP reprocessing did not diminish the efficacy of N95 respirators based on the 4 metrics we assessed: filtration rate, seal check, qualitative fit, and quantitative fit. Of significance, the filtration rate remained well above the 95% standard filtration for N95 respirators—even through 25 cycles of reprocessing. VHP reprocessing is a safe, viable strategy to disinfect N95 respirators and extend their use, particularly during supply shortages.Funding: NoDisclosures: None

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