Bioinspired Structures Made of Silicone Nanofilaments for Upcycling Waste Masks to Reusable N95 Respirators.

The increasing demand for personal protective equipment such as single-use masks has led to large amounts of nondegradable plastic waste, aggravating economic and environmental burdens. This study reports a simple and scalable approach for upcycling waste masks via a chemical vapor deposition technique, realizing a trichome-like biomimetic (TLB) N95 respirator with superhydrophobicity (water contact angle ≥150°), N95-level protection, and reusability. The TLB N95 respirator comprising templated silicone nanofilaments with an average diameter of ∼150 nm offers N95-level protection and breathability comparable to those of commercial N95 respirators. The TLB N95 respirator can still maintain its N95-level protection against particulate matter and viruses after 10 disinfection treatment cycles (i.e., ultraviolet irradiation, microwave irradiation, dry heating, and autoclaving), demonstrating durable reusability. The proposed strategy provides new insight into upcycle waste masks, breaking the existing design and preparation concept of reusable masks.

Riboflavin based setup as an alternative method for a preliminary screening of face mask filtration efficiency.

Face masks are essential in reducing the transmission of respiratory infections and bacterial filtration efficiency, a key parameter of mask performances, requires the use of Staphylococcus aureus and specialised staff. This study aims to develop a novel method for a preliminary screening of masks or materials filtration efficiency by a green, easy and rapid setup based on the use of a riboflavin solution, a safe autofluorescent biomolecule. The proposed setup is composed of a commercial aerosol generator commonly used for aerosol therapy, custom 3D printed aerosol chamber and sample holder, a filter for downstream riboflavin detection and a vacuum pump. The filtration efficiency of four different masks was assessed using the riboflavin-based setup and the bacterial filtration efficiency (BFE). The averaged filtration efficiency values, measured with both methods, were similar but were higher for the riboflavin-based setup (about 2% for all tested samples) than bacterial filtration efficiency. Considering the good correlation, the riboflavin-based setup can be considered validated as an alternative method to bacterial filtration efficiency for masks and related materials fabrics filtration efficiency screening but This study aims to develop a novel method for a preliminary screening of masks or materials filtration efficiency by a green, easy and rapid setup based on the use of a riboflavin solution, a safe autofluorescent biomolecule, but not to replace regulation approaches. The proposed setup can be easily implemented at low price, is more rapid and eco-friendly and can be performed in chemical-physical laboratories without the needing of biosafety laboratory and specialised operators.

Switches in non-invasive respiratory support strategies during acute hypoxemic respiratory failure: Need to monitoring from a retrospective observational study

Objective To explore combined non-invasive-respiratory-support (NIRS) patterns, reasons for NIRS switching, and their potential impact on clinical outcomes in acute-hypoxemic-respiratory-failure (AHRF) patients. Design Retrospective, single-center observational study. Setting Intensive Care Medicine. Patients AHRF patients (cardiac origin and respiratory acidosis excluded) underwent combined NIRS therapies such as non-invasive-ventilation (NIV) and High-Flow-Nasal-Cannula (HFNC). Interventions Patients were classified based on the first NIRS switch performed (HFNC-to-NIV or NIV-to-HFNC), and further specific NIRS switching strategies (NIV trial-like vs. Non-NIV trial-like and single vs. multiples switches) were independently evaluated. Main variables of interest Reasons for switching, NIRS failure and mortality rates. Results A total of 63 patients with AHRF were included, receiving combined NIRS, 58.7% classified in the HFNC-to-NIV group and 41.3% in the NIV-to-HFNC group. Reason for switching from HFNC to NIV was AHRF worsening (100%), while from NIV to HFNC was respiratory improvement (76.9%). NIRS failure rates were higher in the HFNC-to-NIV than in NIV-to-HFNC group (81% vs. 35%, p < 0.001). Among HFNC-to-NIV patients, there was no difference in the failure rate between the NIV trial-like and non-NIV trial-like groups (86% vs. 78%, p = 0.575) but the mortality rate was significantly lower in NIV trial-like group (14% vs. 52%, p = 0.02). Among NIV to HFNC patients, NIV failure was lower in the single switch group compared to the multiple switches group (15% vs. 53%, p = 0.039), with a shorter length of stay (5 [2–8] vs. 12 [8–30] days, p = 0.001). Conclusions NIRS combination is used in real life and both switches’ strategies, HFNC to NIV and NIV to HFNC, are common in AHRF management. Transitioning from HFNC to NIV is suggested as a therapeutic escalation and in this context performance of a NIV-trial could be beneficial. ... (AU)

Objetivo Explorar los patrones combinados de soporte-respiratorio-no-invasivo (SRNI), las razones para cambiar de SRNI y su potencial impacto en los resultados clínicos en pacientes con insuficiencia-respiratoria-aguda-hipoxémica (IRAH). Diseño Estudio observacional retrospectivo unicéntrico. Ámbito Cuidados Intensivos. Pacientes Pacientes con IRAH (excluyendo causa cardíaca y acidosis respiratoria) que recibieron tanto ventilación-no-invasiva (VNI) como cánula-nasal-de-alto-flujo (CNAF). Intervenciones Se categorizó a los pacientes según el primer cambio de SRNI realizado (CNAF-to-VNI o VNI-to-CNAF) y se evaluaron estrategias específicas de SRNI (VNI trial-like vs. Non-VNI trial-like y cambio único vs. múltiples cambios de NIRS) de manera independiente. Variables de interés principales Razones para el cambio, así como las tasas de fracaso de SRNI y la mortalidad. Resultados Un total de 63 pacientes recibieron SRNI combinado, 58,7% clasificados en el grupo CNAF-to-VNI y 41,3% en el grupo VNI-to-CNAF. Los cambios de CNAF a VNI ocurrieron por empeoramiento de la IRHA (100%) y de VNI a CNAF por mejora respiratoria (76.9%). Las tasas de fracaso de SRNI fueron mayores de CNAF a VNI que de VNI a CNAF (81% vs. 35%, p < 0.001). Dentro de los pacientes de CNAF a VNI, no hubo diferencia en las tasas de fracaso entre los grupos VNI trial-like y no-VNI trial-like (86% vs. 78%, p = 0.575), pero la mortalidad fue menor en el grupo VNI trial-like (14% vs. 52%, p = 0.02). Dentro de los pacientes de VNI a CNAF, el fracaso de VNI fue menor en grupo de cambio único vs. múltiple (15% vs. 53%, p = 0.039). Conclusiones Los cambios de estrategia de SRNI son comunes en el manejo clínico diario de la IRHA. El cambio de CNAF a VNI impresiona de ser una escalada terapéutica y en este contexto la realización de un VNI-trial puede ser beneficioso. Al contrario, cambiar de VNI a CNAF impresiona de ser una desescalada terapéutica y parece segura si no hay fracaso ... (AU)

An antimicrobial zinc ion fiber for COVID-19 prevention in nonwoven face coverings for healthcare settings.

The COVID-19 pandemic created an unprecedented increase in the usage of personal protective equipment (PPE) in the healthcare industry, especially in the form of face coverings. Subsequently, guidelines related to breathability and wear comfort were published by the Centers for Disease Control (CDC) as an influx of various new materials entered the PPE market. This study evaluated a proprietary, novel, zinc-ion embedded fiber with the ability to deactivate bacteria and viruses, including SARS-COV-2, for its wear comfort in a nonwoven disposable mask in comparison to a commercially available surgical face mask which served as the control. Ten healthy, full-time, career, firefighters participated in this study wearing both masks in a randomized fashion. A medical task simulation (MTS) protocol was developed to replicate nursing task metabolic rates, per the compendium of physical activities, via a graded treadmill walking exercise. Participant ratings including ease of mask fit, overall mask comfort, facial comfort, breathability, and facial temperature sensation were recorded before, during, and after the 50-minute protocol in a controlled environmental chamber. The 100% nylon, zinc ion mask was rated as slightly cooler at the beginning of the trial (at 0.8 vs. 1.3), than the commercially available polypropylene mask. The polypropylene mask also reached a perceived mask facial comfort (MFC) rating of 1.6 just 35 min into the protocol whereas the zinc ion mask did not reach a rating of slight discomfort until the end of the exercise. Findings indicate the novel zinc-ion embedded mask was as comfortable, if not more so, than the commercially available nonwoven mask with more favorable ratings for longer durations. Not only do the zinc properties provide enhanced protection, but they maintain, if not improve, wearer comfort.

Design of customizable personal protective equipment for 3-D printing: Performance evaluation of N95 respirators using computational fluid dynamics.

3-D printing the structural components of facemasks and personal protective equipment (PPE) based on 3-D facial scans creates a high degree of customizability. As a result, the facemask fits more comfortably with its user's specific facial characteristics, filters contaminants more effectively with its increased sealing effect, and minimizes waste with its cleanable and reusable plastic structure compared to other baseline models. In this work, 3-D renditions of the user's face taken with smartphone laser scanning techniques were used to generate customized computer-aided design (CAD) models for the several components of an N95 respirator, which are each designed with considerations for assembly and 3-D printing constraints. Thorough analyses with computational fluid dynamics (CFD) simulations were carried out to verify the respirator's efficiency in filtering airborne contaminants to comply with industry safety guidelines and generate data to showcase the relationships between various input and output design parameters. This involved a comparative study to identify the ideal cross-sectional geometry of exposed filter fabric, a sensitivity study to evaluate the respirator's ability to protect the user in various scenarios, and the 3-D printing of several prototypes to estimate printing time, cost of materials, and comfort level at the user's face. Results showed that the combination of different digital tools can increase efficiency in the design, performance assessment, and production of customized N95-rated respirators.

N95 respirators alter facial skin physiological functions and lipidome composition in health care personnel.

BACKGROUND: During the coronavirus disease 2019 pandemic, wearing medical respirators and masks was essential to prevent transmission. OBJECTIVE: To quantify the effects of N95 mask usage by measuring facial skin biophysical characteristics and changes in the lipidome. METHODS: Sixty healthy volunteers wore N95 respirators for 3 or 6 h. Facial images were acquired and physiological parameters were measured in specific facial areas, before and after mask-wearing. Lipidome analysis was also performed. RESULTS: After N95 respirator usage, facial erythema was observed in both the 3 and 6 h groups. Both sebum secretion and trans-epidermal water loss increased significantly in mask-covered cheeks and chins after 6 h of mask wearing compared with before mask wearing (p < 0.05). Principal component analysis revealed significant differences in lipid composition after mask wearing compared with before. The ceramide subclass NS exhibited a positive correlation with stratum corneum hydration, whereas the AP subclass was negatively correlated with trans-epidermal water loss in the 6 h group. CONCLUSION: Prolonged wear of N95 respirators may impair facial skin function and alter lipidome composition.

Effective volume of rebreathed air during breathing with facepieces increases with protection class and decreases with ambient airflow.

Wearing facepieces is discussed in the context of increasing the volume of rebreathed air. We hypothesized that rebreathed air volume increases with increasing filtering facepiece (FFP) class and that persons breathing via facepieces compensate for the additional dead-space. We have determined the effective amount of rebreathed air for a surgical masks and FFP2 and FFP3 respirators in a physical model and determined tidal volumes, breathing frequency, blood oxygen saturation, and transcutaneously measured blood carbon dioxide partial pressure (PCO2) in lung-healthy subjects breathing without and with facepieces at rest and during exercising on a recumbent ergometer. Rebreathed air volume increased with the facepieces' protection class and with increasing inspiration volume by 45 ± 2 ml to 247 ± 1 ml. Ambient airflow reduced rebreathed air volume by 17% up to 100% (all p < 0.001). When wearing facepieces, subjects increased tidal volume (p < 0.001) but not breathing frequency. Oxygen saturation was not influenced by facepieces. With FFP3 respirators PCO2 increased by up to 3.2 mmHg (p < 0.001) at rest but only up to 1.4 mmHg (p < 0.001) when exercising. Discomfort of breathing increased with increasing protection class of the facepiece but was consistently perceived as tolerable. We conclude that the amount of rebreathed air increases with increasing protection class of facepieces. Healthy adults were capable to compensate the facepieces' dead-space by adapting tidal volume at rest and during physical activity; thereby they tolerated moderate increases in PCO2. Ambient airflow may considerably reduce the amount of facepiece related rebreathed air.

Respiratory fit test panel representing population of Malaysia.

BACKGROUND: The existing respiratory fit test panels (RFTPs) are based on Bivariate and Principal Component Analysis (PCA) which utilise American and Chinese head and facial dimensions. As RFTPs based on local facial anthropometric data for Malaysia are not available, this study was conducted with the aim to develop new RFTPs using Malaysian data. METHODOLOGY: A cross-sectional study was conducted across Malaysia among 3,324 participants of the study of National Health and Morbidity Survey 2020 aged 18 and above. Ten head and facial dimensions were measured. Face length and face width were used to construct bivariate facial panel, whereas the scores from the first two PCA were used to develop the PCA panel. RESULTS: This study showed that Malaysians have the widest upper limit for facial width. It also found that three factors could be reduced from the PCA analysis. However only 2 factors were selected with PCA 1 representing head and facial size and PCA 2 representing facial shape. Our bivariate panel could accommodate 95.0% of population, while our PCA panel accommodated 95.6%. CONCLUSION: This was the first study to use Malaysian head and facial anthropometry data to create bivariate and PCA panels. Respirators constructed using these panels are likely to fit ≥ 95.0% of Malaysia's population.

Comparison of the inward leakage rate between N95 filtering facepiece respirators and modified surgical masks during the COVID-19 pandemic.

BACKGROUND: Owing to shortage of surgical and N95 filtering facepiece respirators (FFRs) during the COVID-2019 pandemic, various masks were developed to prevent infection. This study aimed to examine the inward leakage rate (ILR) of sealed face masks and modified surgical masks using a quantitative fit test and compared it with the ILR of unmodified N95 FFRs. METHODS: We conducted paired comparisons of ILRs of bent nose-fit wire masks, double masks, and N95 FFRs from October to December 2021. To measure the protective effectiveness of masks, participants wore masks, and the number of particles outside and inside the mask were measured. The ILR was based on the percentage of particles entering the mask using a fit tester. RESULTS: We enrolled 54 participants (20 men and 34 women) in this study. The median ILR for surgical masks without and with a W-shaped bend in the nose-fit wire were 96.44% and 50.82%, respectively. The nose-fit wire adjustment reduced the ILR of surgical masks by a mean of 28.57%, which was significantly lower than the ILR without adjustment (P < 0.001). For double masks, with surgical or polyurethane masks on top of the W-shaped mask, the ILR did not differ significantly from that of N95. Although the filtration performance of double surgical masks matched that of N95 masks, their ILR was notably higher, indicating that double masks do not provide equivalent protection. CONCLUSIONS: Wearing N95 masks alone is effective in many cases. However, surgical mask modifications do not guarantee consistent effectiveness. Properly selected, sealed masks with a good fit overcome leakage, emphasizing their crucial role. Without evidence, mask-wearing may lead to unexpected infections. Education based on quantitative data is crucial for preventing adverse outcomes.

Face anthropometry for filtering facepiece respirators: analysis of the association between facial dimensions and respirator fit.

OBJECTIVE: Ensuring proper respirator fit for individuals remains a persistent challenge in occupational environments, yet there is limited knowledge about how respirators interact with the face to "'fit." Previous studies have attempted to understand the association between face dimensions and respirator fit using traditional head/face anthropometry not specifically tailored for respirators. The purpose of this study was to assess and compare the ability of filtering facepiece respirator (FFR)-specific face anthropometry with traditional head/face anthropometry in exploring the relationship between facial dimensions and the fit of FFR. METHODS: The study utilized 3D face scans and quantitative fit factor scores from 56 participants to investigate the relationship between face anthropometry and FFR fit. Both FFR-specific and traditional anthropometric measurements were obtained through 3D anthropometric software. Intra-correlation of anthropometry was analyzed to evaluate the efficiency and effectiveness of FFR-specific and traditional anthropometry respectively. Principal component analysis (PCA) was conducted to test the usefulness of the PCA method for investigating various facial features. Logistic regression was used to develop fit association models by estimating the relationship between each face measurement set and the binary outcome of the fit test result. The prediction accuracy of the developed regression models was tested. RESULTS: FFR-specific face anthropometry consists of a set of measurements that can inform the detailed facial shape associated with the FFRs more effectively than traditional head/face anthropometry. While PCA may have been effective in reducing the variable dimensions for the relatively large parts of the human body such as upper and lower bodies in previous literature, PCA results of FFR-specific and traditional anthropometry were inconsistent and insufficient to describe face dimensions with complex anatomy in a small-detailed area, suggesting that facial shape should be understood through a variety of approaches including statistical methods. Logistic regression analysis results confirmed that the association models of FFR-specific face anthropometry were significant with higher prediction accuracy and had a better model's goodness of fit than those of traditional head/face anthropometry in 3 conditions inputting all measurements, all PC scores, or top 5 measurements from PCA. CONCLUSIONS: The findings showed that the FFR fit association model enables an understanding of the detailed association between face and respirator fit and allows for the development of a system to predict respirator fit success or failure based on facial dimensions. Future research would include testing the validity of the model and FFR-specific measurement set on different respirator types, expanding the population set, and developing an integrated approach using automated and machine learning technologies to inform FFR selection for occupation workers and the general population.

Use, failure, and non-compliance of respiratory personal protective equipment and risk of upper respiratory tract infections-A longitudinal repeated measurement study during the COVID-19 pandemic among healthcare workers in Denmark.

INTRODUCTION: Upper respiratory tract infections (URTI) are common and a common cause of sick-leave for healthcare workers, and furthermore pose a threat especially for patients susceptible to other diseases. Sufficient use of respiratory protective equipment (RPE) may protect both the workers and the patients. The COVID-19 pandemic provided a unique opportunity to study the association between use of RPE and URTI in a real-life setting. The aim of this study was to examine if failure of RPE or non-compliance with RPE guidelines increases the risk of non-COVID-19 URTI symptoms among healthcare workers. METHODS: In a longitudinal cohort study, we collected self-reported data daily on work tasks, use of RPE, and URTI symptoms among healthcare workers with patient contact in 2 Danish Regions in 2 time periods during the COVID-19 pandemic. The association between failure of RPE or non-compliance with RPE guidelines and URTI symptoms was analyzed separately by generalized linear models. Persons tested positive for severe acute respiratory syndrome coronavirus 2 were censored from the analyses. The 2 waves of data collection were analyzed separately, as there were differences in recommendations of RPE during the 2 waves. RESULTS: We found that for healthcare workers performing work tasks with a risk of transmission of viruses or bacteria, failure of RPE was associated with an increased risk of URTI symptoms, RR: 1.65[0.53-5.14] in wave 1 and RR: 1.30[0.56-3.03] in wave 2. Also non-compliance with RPE guidelines was associated with an increased risk of URTI symptoms compared to the use of RPE in wave 1, RR: 1.28[0.87-1.87] and wave 2, RR: 1.39[1.01-1.91]. Stratifying on high- versus low-risk tasks showed that the risk related to failure and non-compliance was primarily associated with high-risk tasks, although not statistically significant. DISCUSSION: The study was conducted during the COVID-19 pandemic and thus may be affected by other preventive measures in society. However, this gave the opportunity to study the use of RPE in a real-life setting, also in departments that did not previously use RPE. The circumstances in the 2 time periods of data collection differed and were analyzed separately and thus the sample size was limited and affected the precision of the estimates. CONCLUSION: Failures of RPE and non-compliance with RPE guidelines may increase the risk of URTI, compared to those who reported use of RPE as recommended. The implications of these findings are that the use of RPE to prevent URTI could be considered, especially while performing high-risk tasks where other prevention strategies are not achievable.

Australian health care workers experience of PPE related side-effects. A cross-sectional survey.

Introduction: Protection of health care workers (HCWs) is a fundamental aspect of an effective pandemic response. During the COVID-19 pandemic, frequency, and duration of Personal Protective Equipment (PPE) use increased. The experience of PPE-related side-effects has potential to contribute to decreased compliance resulting in breaches in infection prevention and increasing risk of HCW exposure. This study aims were to measure the frequency of PPE-related side-effects amongst HCW in Australia, and to establish if an increased frequency of adverse reactions was related to the significant increase in use and extended duration of time spent in PPE. Methods: A descriptive cross-sectional survey was used. Results: Of the 559 respondents the majority were female (83.7%), aged 31-45 years old (33.6%). A pre-existing skin condition was reported by 266 (47.6%). Frequency of PPE related side-effects were: pressure-related 401 (71.7%), skin 321 (57.4%) and respiratory 20 (3.6%). Surgical mask use was significantly associated with pre-exiting skin conditions (ß = 1.494 (SE 0.186), df (1), p < 0.001). Side effects to N95 respirator use was more commonly reported by staff working in COVID-19 high-risk areas (ß = 0.572 (SE 0.211), df (1), p = 0.007) independent of work duration (ß = -0.056 (SE 0.075), df (1), p = 0.456), and pre-existing skin conditions (ß = 1.272, (SE.198), df (1), p < 0.001). Conclusion: The COVID-19 pandemic has seen a significant increase in the use of PPE. While the preventative benefits of PPE are significant, adverse events related to PPE use are frequently reported by HCW. Findings in this study highlight the need for innovation in PPE design to maximize protection while decreasing adverse effects and maintaining adhere to use.

Using the Number of N95® Filtering Facepiece Respirator Models as an Indicator of Supply Chain Stability in a US Health-Care System.

OBJECTIVES: Personal protective equipment (PPE) supply chain disruptions force US health-care entities to adopt conservation strategies such as procurement from different respirator manufacturers. This research seeks to better understand how the number of respirator models on hand can serve as an indicator of N95 filtering facepiece respirator (FFR) supply chain stability or disruption. METHODS: Researchers looked at differences in the mean number of N95 FFR models, averaged weekly, from 10 hospitals in a health-care system over 15 wk from June 1 to September 10, 2020. Participating hospitals entered near-daily PPE inventory data by manufacturer and model number. RESULTS: A linear mixed effect model was run in SPSS v. 26 using a random intercept for hospitals, with week as a fixed predictor and mean number of respirator models (averaged weekly) on hand as the dependent variable. Each week showed a small but significant effect compared with the past week (P < 0.001), where the average weekly number of respirator models on hand decreased. CONCLUSIONS: The limited data may indicate a resolution of supply chain disruptions and warrant further investigation. Consequently, the number of respirator models may be applicable as an indicator of supply chain stability and be more easily ascertained and tracked by health-care entities.

aPDI meets PPE: photochemical decontamination in healthcare using methylene blue-where are we now, where will we go?

Personal protective equipment (PPE) reuse, first recommended in the context of the SARS-CoV-2 pandemic, can mitigate shortages in crisis situations and can greatly reduce the environmental impact of typically single-use PPE. Prior to safe reuse, PPE must be sanitized and contaminating pathogens-in current circumstances viruses in particular-must be inactivated. However, many established decontamination procedures are not equitable and remain unavailable in low-resource settings. In mid-2020, an interdisciplinary consortium of researchers first studied the potential of implementing cheap and easy-to-use antimicrobial photodynamic inactivation (aPDI) using methylene blue as photosensitizer to decontaminate face masks and filtering facepiece respirators. In this perspective piece, we describe the development of this novel method, discuss recent advances, and offer insights into how equitable PPE decontamination via methylene blue-based aPDI may be integrated into circular economy policies in the healthcare sector.

Incidence of Fit Test Failure During N95 Respirator Reuse and Extended Use.

Importance: The COVID-19 pandemic resulted in a widespread acute shortage of N95 respirators, prompting the Centers for Disease Control and Prevention to develop guidelines for extended use and limited reuse of N95s for health care workers (HCWs). While HCWs followed these guidelines to conserve N95s, evidence from clinical settings regarding the safety of reuse and extended use is limited. Objective: To measure the incidence of fit test failure during N95 reuse and compare the incidence between N95 types. Design, Setting, and Participants: This prospective cohort study, conducted from April 2, 2021, to July 15, 2022, at 6 US emergency departments (EDs), included HCWs who practiced N95 reuse for more than half of their clinical shift. Those who were unwilling to wear an N95 for most of their shift, repeatedly failed baseline fit testing, were pregnant, or had facial hair or jewelry that interfered with the N95 face seal were excluded. Exposures: Wearing the same N95 for more than half of each clinical shift and for up to 5 consecutive shifts. Participants chose an N95 model available at their institution; models were categorized into 3 types: dome (3M 1860R, 1860S, and 8210), trifold (3M 1870+ and 9205+), and duckbill (Halyard 46727, 46767, and 46827). Participants underwent 2 rounds of testing using a different mask of the same type for each round. Main Outcomes and Measures: The primary outcome was Occupational Safety and Health Administration-approved qualitative fit test failure. Trained coordinators conducted fit tests after clinical shifts and recorded pass or fail based on participants tasting a bitter solution. Results: A total of 412 HCWs and 824 N95s were fit tested at baseline; 21 N95s (2.5%) were withdrawn. Participants' median age was 34.5 years (IQR, 29.5-41.8 years); 252 (61.2%) were female, and 205 (49.8%) were physicians. The overall cumulative incidence of fit failure after 1 shift was 38.7% (95% CI, 35.4%-42.1%), which differed by N95 type: dome, 25.8% (95% CI, 21.2%-30.6%); duckbill, 28.3% (95% CI, 22.2%-34.7%); and trifold, 61.3% (95% CI, 55.3%-67.3%). The risk of fit failure was significantly higher for trifold than dome N95s (adjusted hazard ratio, 1.75; 95% CI, 1.46-2.10). Conclusions and Relevance: In this cohort study of ED HCWs practicing N95 reuse, fit failure occurred in 38.7% of masks after 1 shift. Trifold N95s had higher incidence of fit failure compared with dome N95s. These results may inform pandemic preparedness, specifically policies related to N95 selection and reuse practices.

Evaluation of the effects of wiping decontamination for filter cartridges of elastomeric half-mask respirators (EHMRs).

BACKGROUND: A major concern among health care experts is a shortage of N95 filtering facepiece respirators during a pandemic. If the supply of N95 filtering facepiece respirators becomes limited, reusable elastomeric half-mask respirators (EHMRs) may be used to protect health care workers. The focus of this study was to evaluate the effects on the filter performance of wiping decontamination for EHMR P100 filter cartridges. METHODS: The filter cartridge exterior of EHMR Honeywell, Moldex, and Mine Safety Appliance (MSA) models was wiped using quaternary ammonium and sodium hypochlorite wipes. These filter cartridge properties were assessed including observational analysis and filter performance tests. These wiping and assessing procedures were repeated after each set of wiping cycles (50, 100, 150, 200, and 400 cycles) to determine the effects of wiping decontamination. RESULTS: For sodium hypochlorite wipes, Honeywell, Moldex, and MSA models passed the National Institute for Occupational Safety and Health (NIOSH) liquid particulate penetration criteria for all wiping cycles from 50 to 400 (penetrations<0.014%). For quaternary ammonium wipes, filter penetrations of Moldex failed (penetrations>0.03%) after 150 cycles, while the filter penetrations of Honeywell and MSA passed for all wiping cycles (penetrations ≤0.013%). CONCLUSIONS: Wiping decontamination methods using sodium hypochlorite and quaternary ammonium wipes could be considered promising decontamination candidates for Honeywell, Moldex, and MSA reuse, except for the wiping number selection for Moldex (<150 cycles) when using the quaternary ammonium wipe.

P2/N95 fit testing and the risk of COVID-19 in Healthcare Workers.

BACKGROUND: Guidelines recommend healthcare workers (HCWs) undertake fit testing of P2/N95 respirators to mitigate the risk of infectious aerosols, however few studies have assessed whether fit testing reduces COVID-19 infection. METHODS: A retrospective cohort study was conducted amongst HCWs across two tertiary health services in Melbourne, Australia during a period of low community transmission. Institution-wide quantitative fit testing and detailed questionnaires assessing COVID-19 acquisition risk factors were undertaken from September 2020. HCWs diagnosed with COVID-19 in the period prior to the fit testing program (February 1st - August 31st 2020) were matched on a 1:3 ratio to HCWs who had not been diagnosed with COVID-19. Risk factors for COVID-19 acquisition, including fit testing outcome, were compared between groups. RESULTS: A total of 1571 HCWs took part in fit testing programs. Seventy-two (4.6%) were diagnosed with COVID-19 within the study period. Younger age, nursing staff, close contact with a COVID-19 case, and working longer periods in wards with COVID-19 patients, were associated with COVID-19 infection. After matching for intensity of occupational exposure to infectious aerosols, close contact was the only independent variable associated with COVID-19 infection (OR 3.50, 95% CI:1.65-7.44, p = 0.001). Adequate fit test for the respirator predominately worn before the fit testing period was not associated with COVID-19 (OR 1.08, 95% CI:0.59-1.98, p = 0.815). CONCLUSION: After controlling for intensity of occupational exposure to infectious aerosols, P2/N95 respirator fit testing was not associated with reduced risk of COVID-19 infection. The utility of widespread fit testing to reduce HCW COVID-19 infections should be reconsidered.

Prospective comprehensive evaluation of an elastic-band beard cover for filtering facepiece respirators in healthcare workers.

OBJECTIVE: To undertake a healthcare-based multimodal evaluation of the combination of filtering facepiece respirator (FFR) with the elastic-band beard cover technique, including quantitative fit test (QNFT) results, skills assessment, and usability assessment. DESIGN AND SETTING: We conducted a prospective study through the Respiratory Protection Program at the Royal Melbourne Hospital from May 2022 to January 2023. PARTICIPANTS: Healthcare workers who required respiratory protection and could not shave for religious, cultural, or medical reasons. INTERVENTION: Online education and personal face-to-face training on the use of FFR with the elastic-band beard cover technique. RESULTS: Among 87 participants (median beard length 38 mm; interquartile range [IQR], 20-80), 86 (99%) passed 3 QNFTs consecutively with the elastic-band beard cover under a Trident P2 respirator and 68 (78%) passed 3 QNFTs consecutively with a 3M 1870+ Aura respirator. The first QNFT pass rate and the overall fit factors were significantly higher when using the technique than without the elastic-band beard cover. Most participants displayed a high skill level in their donning, doffing, and user seal-check techniques. Of 87 participants, 83 (95%) completed the usability assessment. The overall ease of use, comfort, and overall assessment were rated highly. CONCLUSIONS: The elastic-band beard cover technique can provide safe and effective respiratory protection for bearded healthcare workers. The technique was easily taught, comfortable, well tolerated and accepted by healthcare workers, potentially allowing them full participation in the workforce during pandemics with airborne transmission. We recommend further research and evaluation of this technique in a broader health workforce.

Annual N95 respirator fit-testing: an unnecessary burden on healthcare.

US regulations mandate annual N95 mask fit testing for healthcare workers, but the optimal testing interval is unknown. In our study using data from 12,565 healthcare workers, the probability of survival free from fit-test failure after 3 years was 99.4%, suggesting that less frequent fit testing every 3 years would be safe.