Qualitative Fit Research Articles

Aerosolized Hydrogen Peroxide Decontamination of N95 Respirators, with Fit-Testing and Viral Inactivation, Demonstrates Feasibility for Reuse during the COVID-19 Pandemic.

ABSTRACTIn response to the demand for N95 respirators by health care workers during the COVID-19 pandemic, we evaluated decontamination of N95 respirators using an aerosolized hydrogen peroxide (aHP) system. This system is designed to dispense a consistent atomized spray of aerosolized, 7% hydrogen peroxide (H2O2) solution over a treatment cycle. Multiple N95 respirator models were subjected to 10 or more cycles of respirator decontamination, with a select number periodically assessed for qualitative and quantitative fit testing. In parallel, we assessed the ability of aHP treatment to inactivate multiple viruses absorbed onto respirators, including phi6 bacteriophage, herpes simplex virus 1 (HSV-1), coxsackievirus B3 (CVB3), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For pathogens transmitted via respiratory droplets and aerosols, it is critical to address respirator safety for reuse. This study provided experimental validation of an aHP treatment process that decontaminates the respirators while maintaining N95 function. External National Institute for Occupational Safety & Health (NIOSH) certification verified respirator structural integrity and filtration efficiency after 10 rounds of aHP treatment. Virus inactivation by aHP was comparable to the decontamination of commercial spore-based biological indicators. These data demonstrate that the aHP process is effective, with successful fit-testing of respirators after multiple aHP cycles, effective decontamination of multiple virus species, including SARS-CoV-2, successful decontamination of bacterial spores, and filtration efficiency maintained at or greater than 95%. While this study did not include extended or clinical use of N95 respirators between aHP cycles, these data provide proof of concept for aHP decontamination of N95 respirators before reuse in a crisis-capacity scenario.IMPORTANCE The COVID-19 pandemic led to unprecedented pressure on health care and research facilities to provide personal protective equipment. The respiratory nature of the SARS-CoV2 pathogen makes respirator facepieces a critical protective measure to limit inhalation of this virus. While respirator facepieces were designed for single use and disposal, the pandemic increased overall demand for N95 respirators, and corresponding manufacturing and supply chain limitations necessitated the safe reuse of respirators when necessary. In this study, we repurposed an aerosolized hydrogen peroxide (aHP) system that is regularly utilized to decontaminate materials in a biosafety level 3 (BSL3) facility, to develop a method for decontamination of N95 respirators. Results from viral inactivation, biological indicators, respirator fit testing, and filtration efficiency testing all indicated that the process was effective at rendering N95 respirators safe for reuse. This proof-of-concept study establishes baseline data for future testing of aHP in crisis-capacity respirator-reuse scenarios.

Development of respirator design for children using bamboo-based activated carbon filter and bipolar ionization

This paper proposes a respirator for children integrated with bamboo-based activated carbon filters and bipolar ionization as the sterilizer to increase protection from Covid-19 and other pathogens. The respirator, named as Bion-Kids, was designed based on the children's head-and-face anthropometry from direct measurement. The duration of sterilization process is controlled based on the activities, which are classified using the Recurrent Neural Network (RNN) model with dataset acquired from the accelerometer. Manufacturing process of the main body prototype comprises heat bending and 3D printing. The bamboo-based activated carbon filter was synthesized by applying heat and pressure at the strewed activated carbon particles on the N95 filter. Observation using scanning electron microscope showed the ability of the bamboo-based activated carbon filter to adsorb and trap the particles. Result of the qualitative fit test and questionnaire survey indicated that Bion-Kids is suitable and comfortable for the children's face. The result of filtration and bipolar ionization sterilization system analysis have also met the ISO14698 standard by not showing any infiltration of microorganisms on the blood agar media. This device may become an early-stage personal protective equipment against the transmission of Covid-19 and other pathogens.

The effect of plastic tape seal to reduce face seal leak in respirator N-95 type 1860

The risk of face seal leak while using N-95 respirators is experienced by health workers and thus failing fit test are quite common. Finding solutions to overcome face seal leaks is crucial; one of which is by sealing the N-95 respirator. The seal used in this research was Tegaderm® a transparent film dressing or a plastic tape which is known to have the advantages of strong adhesion, high level of pore density and standardized medical grade. This study tries to determine the effectiveness of plastic tape adhesive on the N-95 type 1860 respirator in overcoming face seal leak qualitative fit test using Bitrex immediately after being worn and after 4 h of using it. The study used a quantitative approach with an incidence study design conducted pre and post experimental without comparison to see the effectiveness of plastic tape sealing. The subjects for the research were 81 health workers in the CMH environment who were at risk of being exposed to COVID-19. The study found a significant difference in the Bitrex fit test immediately after sealing the N-95 type 1860 respirator with plastic tape; 100% passed the fit test immediately after sealing, and 64.2% passed the fit test after 4 h of working. The effectiveness of sealing using plastic tape is considered to be quite good to overcome face seal leak on the N-95 type 1860 respirator. Health care workers need to be more vigilance to ensure better face seal.

Analysis of cellular kinetic models suggest that physiologically based model parameters may be inherently, practically unidentifiable

Physiologically-based pharmacokinetic and cellular kinetic models are used extensively to predict concentration profiles of drugs or adoptively transferred cells in patients and laboratory animals. Models are fit to data by the numerical optimisation of appropriate parameter values. When quantities such as the area under the curve are all that is desired, only a close qualitative fit to data is required. When the biological interpretation of the model that produced the fit is important, an assessment of uncertainties is often also warranted. Often, a goal of fitting PBPK models to data is to estimate parameter values, which can then be used to assess characteristics of the fit system or applied to inform new modelling efforts and extrapolation, to inform a prediction under new conditions. However, the parameters that yield a particular model output may not necessarily be unique, in which case the parameters are said to be unidentifiable. We show that the parameters in three published physiologically-based pharmacokinetic models are practically (deterministically) unidentifiable and that it is challenging to assess the associated parameter uncertainty with simple curve fitting techniques. This result could affect many physiologically-based pharmacokinetic models, and we advocate more widespread use of thorough techniques and analyses to address these issues, such as established Markov Chain Monte Carlo and Bayesian methodologies. Greater handling and reporting of uncertainty and identifiability of fit parameters would directly and positively impact interpretation and translation for physiologically-based model applications, enhancing their capacity to inform new model development efforts and extrapolation in support of future clinical decision-making.

Improving the fit of filtering facepiece respirators.

Aims To assess the effectiveness and acceptability of smartphone customised frame technology to improve the fit of disposable filtering facepiece class 3 (FFP3) respirators for dental staff who previously failed fit testing.Method In total, 20 volunteers who previously failed FFP3 fit testing were recruited to use smartphone technology (Bellus3D FaceApp) to have a 3D-printed bespoke face frame produced for them. They underwent qualitative fit testing with and without the frame with two freely available disposable FFP3 respirator designs (mask A: GVS F31000 Segre folded model; mask B: Valmy Spireor). The order of testing was random. Ease of use of the smartphone technology and the comfort of the frame were determined by questionnaire.Results Fit test passes increased from 5% without the frame to 70% and 95%, respectively, for masks A and B with the frame (p <0.01). Very few participants reported using the technology as difficult (n = 1/20) or the frame uncomfortable (n = 3/20) or difficult to wear (n = 0/20).Conclusion Customised frames produced using smartphone technology improved qualitative fit test pass rates for two commonly available FFP3 respirators. Using smartphone technology for frame design, wearing a frame and frame comfort levels were all acceptable to the majority of participants.

A framework for characterizing heterogeneity in neurodevelopmental data using latent profile analysis in a sample of children with ADHD

BackgroundHeterogeneity in neurodevelopmental disorders, and attention deficit hyperactivity disorder (ADHD) in particular, is increasingly identified as a barrier to identifying biomarkers and developing standards for clinical care. Clustering analytic methods have previously been used across a variety of data types with the goal of identifying meaningful subgroups of individuals with ADHD. However, these analyses have often relied on algorithmic approaches which assume no error in group membership and have not made associations between patterns of behavioral, neurocognitive, and genetic indicators. More sophisticated latent classification models are often not utilized in neurodevelopmental research due to the difficulty of working with these models in small sample sizes.MethodsIn the current study, we propose a framework for evaluating mixture models in sample sizes typical of neurodevelopmental research. We describe a combination of qualitative and quantitative model fit evaluation procedures. We test our framework using latent profile analysis (LPA) in a case study of 120 children with and without ADHD, starting with well-understood neuropsychological indicators, and building toward integration of electroencephalogram (EEG) measures.ResultsWe identified a stable five-class LPA model using seven neuropsychological indicators. Although we were not able to identify a stable multimethod indicator model, we did successfully extrapolate results of the neuropsychological model to identify distinct patterns of resting EEG power across five frequency bands.ConclusionsOur approach, which emphasizes theoretical as well as empirical evaluation of mixture models, could make these models more accessible to clinical researchers and may be a useful approach to parsing heterogeneity in neurodevelopmental disorders.

Why apply yinyang philosophy in mixed methods research: Harmony perspectives from ancient Chinese culture

Yinyang philosophy encompasses an essential understanding of the mechanism and laws of nature, cosmos, and human society in Chinese culture, and reaches to many other parts of Asia and around the world. The purpose of this article is to explore how yinyang philosophy can serve as a philosophical underpinning of mixed methods research (MMR). In particular, harmony, one of the important features in yinyang philosophy, is applied to interpret the design of mixed methods research. Guided by this philosophy, other beliefs about an integrated approach to using qualitative and quantitative methods fit in with the MMR approach. These underlying precepts are not necessarily held by researchers, and will be shown to indicate harmony and a dynamic equilibrium of yin and yang. This perspective provides a novel window for considering controversial issues that have arisen about the use of different philosophical underpinnings for MMR during its emergence over the past several decades. The implications are for a softer interpretation, for example, when selection of quantitative rules needs to harmonize with certain types of MMR, and validity of self-developed questionnaires needs to consider different levels of criteria for MMR.

Qualitative fit test outcomes for N95 filtering facepiece respirators in health care workers

BackgroundWe analyzed the qualitative fit test results of the filtering facepiece respirators (FFRs) used at our institution to determine their performance and utility. MethodsWe retrospectively analyzed 12,582 qualitative fit testing results for several FFR models among 8,809 health care workers (HCWs). ResultsThe overall failure rate for HCWs was 15.2%. Nearly one-third (2933/8809, 33.3%) had multiple FFRs fit tested. HCW sex was a statistically significant indicator of fit testing failure (χ2 = 29.9, df = 1, P < .001), with women having a 44% higher likelihood (OR, 1.4; 95% CI: 1.27–1.65) than men. There were statistically significant differences in the failure rate across FFRs (Fig 4, F[5, 12475] = 8.4, P < .001). Fluidshield 46867S had a significantly higher failure rate (49%) than the 3M 1860 (P = .012), 3M 1860S (P < .001), 3M 8210 (P < .001), and Safelife (P < .001) FFRs. ConclusionsThere was a large degree of variation in fit testing results for the FFRs tested. Although we were unable to find an FFR that fit more than 95% of the HCWs successfully, we identified poorly functioning FFRs that can help our institution with decision-making and budgeting for acquisition and stocking appropriate FFRs.

Face mask fit hacks: Improving the fit of KN95 masks and surgical masks with fit alteration techniques.

During the course of the COVID-19 pandemic, there have been suggestions that various techniques could be employed to improve the fit and, therefore, the effectiveness of face masks. It is well recognized that improving fit tends to improve mask effectiveness, but whether these fit modifiers are reliable remains unexplored. In this study, we assess a range of common "fit hacks" to determine their ability to improve mask performance. Between July and September 2020, qualitative fit testing was performed in an indoor living space. We used quantitative fit testing to assess the fit of both surgical masks and KN95 masks, with and without 'fit hacks', on four participants. Seven fit hacks were evaluated to assess impact on fit. Additionally, one participant applied each fit hack multiple times to assess how reliable hacks were when reapplied. A convenience of four participants took part in the study, three females and one male with a head circumference range of 54 to 60 centimetres. The use of pantyhose, tape, and rubber bands were effective for most participants. A pantyhose overlayer was observed to be the most effective hack. High degrees of variation were noted between participants. However, little variation was noted within participants, with hacks generally showing similar benefit each time they were applied on a single participant. An inspection of the fit hacks once applied showed that individual facial features may have a significant impact on fit, especially the nose bridge. Fit hacks can be used to effectively improve the fit of surgical and KN95 masks, enhancing the protection provided to the wearer. However, many of the most effective hacks are very uncomfortable and unlikely to be tolerated for extended periods of time. The development of effective fit-improvement solutions remains a critical issue in need of further development.

Assessing changes to N95 respirator filtration efficiency, qualitative and quantitative fit, and seal check with repeated vaporized hydrogen peroxide (VHP) decontamination

N95 respirators were reprocessed using vaporized hydrogen peroxide to supplement limited supplies during the COVID-19 pandemic. In this study, we found no statistically significant differences in qualitative and quantitative fit or filtration efficiency with reprocessing. Filtration efficiency remained above 95% even at 25 cycles of reprocessing without statistically significant change from cycle 20-25 compared to cycle 0 (P=.10, P=.05, respectively). Vaporous hydrogen peroxide is an effective option to augment N95 respirator supplies.

Adequacy of a Novel Qualitative Fit Test Kit and Protocol during the COVID-19 Pandemic.

To develop our own qualitative fit test kit and protocol for respirators and validate this against the manufacturer-issued kit. This is a crossover study of 50 healthcare workers in a tertiary government hospital. Some healthcare workers were tested multiple times according to the number of respirators they want tested. Qualitative fit testing was done according to manufacturer protocol for the commercial kits or according to our own protocol for the novel kits. A total of 63 fit tests were analyzed. This novel kit was determined to be noninferior to manufacturer-issued kits in detecting leaks among worn respirators (p=0.005). A fit test kit can be successfully created from readily available household and hospital materials. Fit tests with these novel kits using our validated protocol are shown to be noninferior to commercial test kits. This can greatly aid in qualitative fit testing of respirators in a logistically constrained pandemic setting.

A position statement and practical guide to the use of particulate filtering facepiece respirators (N95, FFP2, or equivalent) for South African health workers exposed to respiratory pathogens including Mycobacterium tuberculosis and SARS-CoV-2

Summary Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted mainly by aerosol in particles &lt;10 µm that can remain suspended for hours before being inhaled. Because particulate filtering facepiece respirators (‘respirators’; e.g. N95 masks) are more effective than surgical masks against bio-aerosols, many international organisations now recommend that health workers (HWs) wear a respirator when caring for individuals who may have COVID-19. In South Africa (SA), however, surgical masks are still recommended for the routine care of individuals with possible or confirmed COVID-19, with respirators reserved for so-called aerosol-generating procedures. In contrast, SA guidelines do recommend respirators for routine care of individuals with possible or confirmed tuberculosis (TB), which is also transmitted via aerosol. In health facilities in SA, distinguishing between TB and COVID-19 is challenging without examination and investigation, both of which may expose HWs to potentially infectious individuals. Symptom-based triage has limited utility in defining risk. Indeed, significant proportions of individuals with COVID-19 and/or pulmonary TB may not have symptoms and/or test negative. The prevalence of undiagnosed respiratory disease is therefore likely significant in many general clinical areas (e.g. waiting areas). Moreover, a proportion of HWs are HIV-positive and are at increased risk of severe COVID-19 and death. Recommendations Sustained improvements in infection prevention and control (IPC) require reorganisation of systems to prioritise HW and patient safety. While this will take time, it is unacceptable to leave HWs exposed until such changes are made. We propose that the SA health system adopts a target of ‘zero harm’, aiming to eliminate transmission of respiratory pathogens to all individuals in every healthcare setting. Accordingly, we recommend: 1. the use of respirators by all staff (clinical and non-clinical) during activities that involve contact or sharing air in indoor spaces with individuals who: (i) have not yet been clinically evaluated; or (ii) are thought or known to have TB and/or COVID-19 or other potentially harmful respiratory infections; 2. the use of respirators that meet national and international manufacturing standards; 3. evaluation of all respirators, at the least, by qualitative fit testing; and 4. the use of respirators as part of a ‘package of care’ in line with international IPC recommendations. We recognise that this will be challenging, not least due to global and national shortages of personal protective equipment (PPE). SA national policy around respiratory protective equipment enables a robust framework for manufacture and quality control and has been supported by local manufacturers and the Department of Trade, Industry and Competition. Respirator manufacturers should explore adaptations to improve comfort and reduce barriers to communication. Structural changes are needed urgently to improve the safety of health facilities: persistent advocacy and research around potential systems change remain essential.

A position statement and practical guide to the use of particulate filtering facepiece respirators (N95, FFP2, or equivalent) for South African health workers exposed to respiratory pathogens including Mycobacterium tuberculosis and SARS-CoV-2.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted mainly by aerosol in particles <10 µm that can remain suspended for hours before being inhaled. Because particulate filtering facepiece respirators ('respirators'; e.g. N95 masks) are more effective than surgical masks against bio-aerosols, many international organisations now recommend that health workers (HWs) wear a respirator when caring for individuals who may have COVID-19. In South Africa (SA), however, surgical masks are still recommended for the routine care of individuals with possible or confirmed COVID-19, with respirators reserved for so-called aerosol-generating procedures. In contrast, SA guidelines do recommend respirators for routine care of individuals with possible or confirmed tuberculosis (TB), which is also transmitted via aerosol. In health facilities in SA, distinguishing between TB and COVID-19 is challenging without examination and investigation, both of which may expose HWs to potentially infectious individuals. Symptom-based triage has limited utility in defining risk. Indeed, significant proportions of individuals with COVID-19 and/or pulmonary TB may not have symptoms and/or test negative. The prevalence of undiagnosed respiratory disease is therefore likely significant in many general clinical areas (e.g. waiting areas). Moreover, a proportion of HWs are HIV-positive and are at increased risk of severe COVID-19 and death. Sustained improvements in infection prevention and control (IPC) require reorganisation of systems to prioritise HW and patient safety. While this will take time, it is unacceptable to leave HWs exposed until such changes are made. We propose that the SA health system adopts a target of 'zero harm', aiming to eliminate transmission of respiratory pathogens to all individuals in every healthcare setting. Accordingly, we recommend: the use of respirators by all staff (clinical and non-clinical) during activities that involve contact or sharing air in indoor spaces with individuals who: (i) have not yet been clinically evaluated; or (ii) are thought or known to have TB and/or COVID-19 or other potentially harmful respiratory infections;the use of respirators that meet national and international manufacturing standards;evaluation of all respirators, at the least, by qualitative fit testing; andthe use of respirators as part of a 'package of care' in line with international IPC recommendations. We recognise that this will be challenging, not least due to global and national shortages of personal protective equipment (PPE). SA national policy around respiratory protective equipment enables a robust framework for manufacture and quality control and has been supported by local manufacturers and the Department of Trade, Industry and Competition. Respirator manufacturers should explore adaptations to improve comfort and reduce barriers to communication. Structural changes are needed urgently to improve the safety of health facilities: persistent advocacy and research around potential systems change remain essential.

The Effect of Training on Knowledge, Perception, and Practice of Healthcare Personnel on the Use of Respiratory Protective Equipment during COVID-19 Pandemic at a Private Hospital in the Northern part of Thailand.

OBJECTIVES: To determine the effect of the respiratory protective training program of healthcare personnel (HCP) during the Coronavirus Disease 2019 (COVID-19) pandemic at a private hospital in the northern part of Thailand. MATERIALS AND METHODS: This cross-sectional study was conducted with 89 healthcare personnel (HCP) of Bangkok Hospital Phitsanulok, who required wearing a tight-fitting respirator during their duties and attended respiratory protective equipment (RPE) video-based training program regarding the general principles of respirator usage and guidelines on safely re-using RPE. A questionnaire-based assessment of participants’ 3-month retention of knowledge and perception was conducted in April 2021. A qualitative fit test (QLFT) was used in terms of practice on RPE. The proportion of correct responses in the 3-month knowledge and perception score were compared with a pre-training test and an immediate post-training test using paired t-test. The same analysis was conducted with QLFT using McNemar’s test. RESULT: Various types of RPE were used in each test depending on the supply. The most commonly used RPE was N95 (58.4%), the majority of N95 was 3MVLFEX 9105. Compared with the pretraining test, the proportion of correct responses in the immediate post-training test increased by 11% (p &lt; 0.001; 95% CI 1.07-2.23). Similarly, in 3-month post-training, the percentage of correct response also increased from pre-training by 10.4% (p &lt; 0.001; 95% CI 0.08-2.28). HCP had an excellent level of perception on using RPE during COVID-19. No significant change in perception was found between pretraining and both immediate and 3-months after training (p = 0.536 and p = 0.384 respectively) The pass rate significantly raised to 96.6% for an immediate post-training test (p &lt; 0.001) and to 98.8% after 3-month (p &lt; 0.001). CONCLUSION: Training has played an important role to help HCP improve their knowledge and practice regarding the usage of RPE, but has no significant effect on perception. The assessment of knowledge, perception and practice retention of RPE usage after 3-month showed the positive impacts of video-based training groups on participants’ knowledge and practice. Further evaluations are needed on the interventions that enhance HPC perceptions and attitudes on safety behavior. Pre- and in-service training programs for frontline HPC during a Coronavirus 19 disease pandemic need to be considered by Thai Ministry of Public Health.

Impact on the fitness of N95 masks with extended use/limited reuse and dry heat decontamination

Substandard use of N95 masks, sometimes combined with dry heat decontamination, lacks safety data. We evaluated the impact of these practices on the fitness of N95 masks. This is a...

Adapted full-face snorkel masks as an alternative for COVID-19 personal protection during aerosol generating procedures in South Africa: A multi-centre, non-blinded in-situ simulation study.

IntroductionSARS-CoV-2 has resulted in increased worldwide demand for personal protective equipment (PPE). With pressure from ongoing epidemic and endemic episodes, we assessed an adapted snorkel mask that provides full-face protection for healthcare workers (HCWs), particularly during aerosol-generating procedures. These masks have a custom-made adaptor which allows the fitment of standard medical respiratory filters. The aim of this study was to evaluate the fit, seal and clinical usability of these masks.MethodsThis multicentre, non-blinded in-situ simulation study recruited fifty-two HCWs to don and doff the adapted snorkel mask. Negative pressure seal checks and a qualitative fit test were performed. The HCWs completed intubation and extubation of a manikin in a university skills training laboratory, followed by a web-based questionnaire on the clinical usability of the masks.ResultsWhilst fit and usability data were generally satisfactory, two of the 52 participants (3.8%) felt that the mask did not span the correct distance from the nose to the chin, and 3 of 34 participants (8.8%) who underwent qualitative testing with a Bitrex test failed. The majority of users reported no fogging, humidity or irritation. It was reportedly easy to speak while wearing the mask, although some participants perceived that they were not always understood. Twenty-one participants (40%) experienced a subjective physiological effect from wearing the mask; most commonly a sensation of shortness of breath.DiscussionA fit-tested modified full-face snorkel mask may offer benefit as a substitute for N95 respirators and face shields. It is, however, important to properly select the correct mask based on size, fit testing, quality of the three-dimensional (3D) printed parts and respiratory filter to be used. Additionally, HCWs should be trained in the use of the mask, and each mask should be used by a single HCW and not shared.

Where do qualitative assessments fit in an era of increasingly quantitative monitoring? Perspectives from Interpreting Indicators of Rangeland Health

Interpreting Indicators of Rangeland Health and other well-designed qualitative assessments are useful for understanding ecological function and can be used to prioritize areas for monitoring, restoration, or management changes. When completed by experienced, trained multidisciplinary teams, qualitative assessments provide reliable information about ecological processes and are repeatable across time and geographic locations. Consistency and repeatability of qualitative assessments are maximized when the assessments are supported by appropriate quantitative indicator data. Likewise, quantitative datasets may be complemented by qualitative assessments, which can provide insight into indicators that are difficult to measure, providing a more complete view of vegetation, soils, and underlying ecological processes. Qualitative assessments can be used as a communication tool for developing a common understanding of resource issues and a shared vision for, and commitment to future stewardship. New opportunities are emerging to enable further integration of qualitative and quantitative field protocols, ecological models, and remotely sensed products to benefit rangeland assessment, monitoring, and management.

Study of the use of a personalized peripheral sealing device on surgical face masks in high-risk situations against COVID-19.

A significant number of health care professionals subjected to high-risk situations have been infected by Covid-19 due to the lack of adequate protection equipment or the deficient safety margins that these present. The aim of this study was to investigate whether the use of a personal peripheral sealing device (PSD) on surgical face masks (SM) allows them to achieve double mask properties, by providing two-way protection to professionals or users. The proposed device is a thermoplastic resin ring composed of a reusable and biodegradable polylactic acid (PLA) designed to be used in a healthcare setting. Since it is a thermoplastic device, it can be molded and adapted to each individual, becoming personalized and ensuring a correct adjustment to the user’s face. First, a qualitative fit test was performed using a saccharin solution (SS) to evaluate respiratory protective equipment in recruited professionals exposed to high-risk situations of infection by Covid-19. Individuals were divided into an intervention group, who used SM with the PSD, and a control group, who used SM without the PSD. In addition, a quantitative inward air leakage fit test was performed using a 2% sodium chloride (NaCl) aerosol in a sealed cabinet with probes sensitive to this substance, in order to validate the SM with the PSD as a Face Filtering Mask (FFP). Only 5% of the individuals who performed the qualitative fit test with the PSD perceived the sweet taste of the SS, while 100% of the individuals who performed the test without the PSD sensed it (p = 0.0001). In the quantitative fit test, the percentage of air leakage of 2% NaCl aerosol into the SM with the PSD was 6.5%, achieving the same range of air leakage as a FFP mask. Thus, the use of a personalized PLA thermoplastic PSD, together with an inexpensive and widely available SM, could have a significant impact in terms of preventive safety by providing bi-directional protection to its user.

Navigating the shifting sands of filtering facepiece respirator provision during the COVID-19 pandemic: a system response for maximising staff safety

IntroductionPersonal protective equipment is essential to protect health workers and patients and to ensure confidence when dealing with aerosolised disease transmission. We describe the process for ensuring adequate filtering facepiece...

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

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 &lt;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 &gt;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