Determining the filtration effectiveness of non-standard respiratory protective devices by an ad-hoc laboratory methodology.

The recent pandemic caused by COVID-19 profoundly changed people's habits. Wearing a face mask has become usual in everyday life to reduce the risk of infection from airborne diseases. At the beginning of the pandemic, the massive request of surgical or filtering face piece (FFP) masks resulted in a global shortage of these devices for the most exposed people, such as healthcare workers. Due to this high demand for respiratory protective devices, many industrial plants have partly converted to the production of face masks using adapted materials and not complying with any specific regulation (non-standard respiratory protective devices or community masks). In this work, an ad-hoc laboratory methodology has been developed to evaluate the filtration efficiency of the materials that compose the community masks using specific instrumentation. The instrumentation consists of three main tools: an aerosol generator, a specifically designed measuring chamber, and an optical particle sizer (OPS) for the measurement of aerosol concentration. The generated aerosol was sent into the measuring chamber, divided into two separate sections by the respiratory mask. The OPS measured the aerosol mass concentration upstream and downstream of the respiratory mask, and from the concentration difference the filtration efficiency was evaluated. The proposed methodology has been validated by evaluating the particle filtration efficiency (PFE) of certified respiratory masks and was then applied for the evaluation of the filtration efficiency of different types of non-standard or community masks to analyze their effectiveness in protecting from the risk of infection of airborne diseases.

Health effects of filtering facepiece respirators: Systematic review of pulmonary and cardiovascular effects.

Filtering facepiece respirators (FFRs) were introduced to protect the wearer by removing small particles from inspired air. FFRs are now also used to reduce the spread of transmissible agents from the wearer and are worn outside traditional healthcare and other workplaces. The COVID-19 pandemic increased concerns about potential adverse effects on wearers. A PUBMED query retrieved articles through June 2022. Abstracts and selected full-text articles were systematically reviewed by the authors. This article focuses upon cardiopulmonary physiologic effects (e.g., ventilation, CO2 elimination, oxygen uptake, and respiratory control) with emphasis upon current and potential research methods as well as summarizing results. 1985 records were identified, of which only 26% were published before 2020. FFR effects on CO2 elimination appear more likely to be significant than effects on oxygenation or cardiovascular function. While FFRs appear well tolerated by healthy persons, more research is needed for those with pulmonary or cardiac disorders, and for children. Many traditional pulmonary exercise study methods require special care when applied to filtering facepiece respirators. Studying additional parameters may explain the paradox of many subjective discomfort reports despite very limited physiologic effects.

Health effects of filtering facepiece respirators: Research and clinical implications of comfort, thermal, skin, psychologic, and workplace effects.

Filtering facepiece respirators (FFR's) such as N95s have become widely used in appropriate settings for personal respiratory protection and are increasingly used beyond workplace settings. Concerns about possible adverse effects have appeared in many publications, particularly since the COVID-19 pandemic led to much more widespread use. This paper synthesizes known effects based upon review of publications in PubMed since 1995, addressing effects other than pulmonary and cardiovascular (reviewed elsewhere). Findings: (1) Subjective discomfort is very frequently reported; this includes general discomfort or organ-system-specific complaints such as respiratory, headache, dermatologic, and heat. Research methods are widely divergent, and we propose a taxonomy to classify such studies by methodology, study population (subjects, experimental vs. observational methodology, comparator, specificity, and timeframe) to facilitate synthesis. (2) Objective measures of increased heat and humidity within the mask are well documented. (3) Frequency and characteristics of dermatologic effects have been insufficiently evaluated. (4) Physical mask designs are varied, making generalizations challenging. (5) More studies of impact on work performance and communication are needed. (6) Studies of effect of FFR design and accompanying training materials on ease and consistency of use are needed.

Using infrared imaging and deep learning in fit-checking of respiratory protective devices among healthcare professionals.

AIMS: This study aimed to investigate the application of infrared thermal imaging and adopt deep learning to detect air leakage for determining the fitness of respirators during fit-checks. BACKGROUND: The outbreak of Covid-19 virus constitutes a public health crisis with substantial resultant morbidities and mortalities; has exerted profound impacts. METHODS: This was a prospective observational study, employing a non-probability sampling method on a convenience sample to recruit the participants and followed the Strengthening the Reporting of Observational Studies in Epidemiology statement guidelines. RESULTS: The use of infrared thermal imaging identified air leakage points as a disruption to the facial thermal pattern distribution at (a) front of face; (b) right lateral of the face; (c) left lateral of the face; (d) top of the facemask with the head facing down; and (e) bottom of the facemask with the head facing up. Results also indicated that artificial intelligence tools and the proliferation of deep learning have the potential to detect the location of air leakage locations. CONCLUSION: The use of infrared thermal imaging provides evidence of the feasibility and applicability of infrared thermal imaging techniques in detecting air leakage for individuals wearing respirators. CLINICAL RELEVANCE: The use of infrared thermal technology can serve a potential role in complement fit-checking of respiratory protective devices and offers promising practical utility in determining the fitness of respirators for nurses at the frontline to protect against the air-borne viruses.

Comparison of ISO work of breathing and NIOSH breathing resistance measurements for air-purifying respirators.

The National Institute for Occupational Safety and Health's methods and requirements for air-purifying respirator breathing resistance in 42 CFR Part 84 do not include work of breathing. The International Organization for Standardization Technical Committee 94, Subcommittee 15 utilized work of breathing to evaluate airflow resistance for all classes of respiratory protective devices as part of their development of performance standards regarding respiratory protective devices. The objectives of this study were: (1) to evaluate the relationship between the International Organization for Standardization's work of breathing measurements and the National Institute for Occupational Safety and Health's breathing resistance test results; (2) to provide scientific bases for standard development organizations to decide if work of breathing should be adopted; and (3) to establish regression equations for manufacturers and test laboratories to estimate work of breathing measurements using breathing resistance data. A total of 43 respirators were tested for work of breathing at minute ventilation rates of 10, 35, 65, 105, and 135 liters per minute. Breathing resistance obtained at a constant flow rate of 85 liters per minute per National Institute of Occupational Safety and Health protocol was correlated to each of the parameters (total work of breathing, inhalation, and exhalation) obtained from the work of breathing tests. The ratio of work of breathing exhalation to work of breathing inhalation for all air-purifying respirators is similar to the ratio of exhalation to inhalation resistance when tested individually. The ratios were about 0.8 for filtering facepiece respirators, 0.5 for half-masks, and 0.25 for full-facepiece respirators. The National Institute for Occupational Safety and Health's breathing resistance is close to work of breathing's minute ventilation of 35 liters per minute, which represents the common walking/working pace in most workplaces. The work of breathing and the National Institute of Occupational Safety and Health's breathing resistance were found to be strongly and positively correlated (r values of 0.7-0.9) at each work rate for inhalation and exhalation. In addition, linear and multiple regression models (R-squared values of 0.5-0.8) were also established to estimate work of breathing using breathing resistance. Work of breathing was correlated higher to breathing resistance for full-facepiece and half-mask elastomeric respirators than filtering facepiece respirators for inhalation. For exhalation, filtering facepiece respirators were correlated much better than full-facepiece and half-mask elastomeric respirators. Therefore, the National Institute for Occupational Safety and Health's breathing resistance may reasonably be used to predict work of breathing for air-purifying respirators. The results could also be used by manufacturers for product development and evaluation.

Validation of krypton as a new tracer gas for the standardization tests of collective and individual protection systems.

Sulfur hexafluoride (SF6) is the reference tracer gas in many international standards for characterizing respiratory protective devices (RPD), fume cupboards, building ventilations, and other installations. However, due to its significant impact on global warming, its use is becoming increasingly restrictive. Krypton 84 (Kr) was chosen to be a possible replacement based on theoretical and practical criteria for the properties that a substitute gas should possess. While compliance with these criteria is generally sufficient to guarantee the reliability of the choice, it is essential in the case of widespread use such as a standard to validate experimentally that this tracer has the same behavior as SF6. In this regard, numerous tests have been carried out to characterize the face leakage of RPD and the rupture of containment of fume cupboards performance tests under different operating conditions. The results obtained are identical with both tracers and lead us to propose the use of Kr as a new reference gas in standards for which SF6 was used.

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.

Face mask performance related to potentially infectious aerosol particles, breathing mode and facial leakage.

During the COVID 19 pandemic, wearing certified Respiratory Protective Devices (RPDs) provided important means of protection against direct and indirect infections caused by virus-laden aerosols. Assessing the RPD performance associated with infection prevention in standardised certification tests, however, faces drawbacks, such as the representativeness of the test aerosols used, the protection of third parties during exhalation or the effect of facial leaks. To address these drawbacks, we designed a novel test bench to measure RPD performance, namely the number based total efficiency, size-segregated fractional filtration efficiency and net pressure loss, for 11 types of certified surgical masks and Filtering Face Pieces dependent on breathing mode and facial fit. To be representative for the context of potentially infectious particles, we use a test aerosol based on artificial saliva that is in its size distribution similar to exhaled aerosols. In inhalation mode excluding facial leaks, all investigated samples deposit by count more than 85% of artificial saliva particles, which suggests a high efficiency of certified RPD filter media related to these particles. In exhalation mode most RPDs tend to have similar efficiencies but lower pressure losses. This deviation tends to be significant primarily for the RPDs with thin filter layers like surgical masks or Filtering Face Pieces containing nanofibers and may depend on the RPDs shape. Both the filtration efficiency and pressure loss are strongly inter-dependent and significantly lower when RPDs are naturally fitted including facial leaks, leading to a wide efficiency range of approximately 30-85%. The results indicate a much greater influence of the facial fit than the filter material itself. Furthermore, RPDs tend be more effective in self-protection than in third-party protection, which is inversely correlated to pressure loss. Comparing different types of RPDs, the pressure loss partially differs at similar filtration efficiencies, which points out the influence of the material and the filter area on pressure loss.

Conducting quantitative mask fit tests: application details and affecting factors.

Introduction: Respirators chosen based on their assigned protection factor (APF) enable wearers to effectively reduce particulate matter concentrations to safe levels when used correctly. As a crucial factor in achieving the intended APF, the fit test has become a necessary procedure in respiratory disease protection. Methods: This study involved 225 participants who underwent a fit test using two reusable types of half masks and two types of full masks. Condensation nuclei counting (CNC) and controlled negative pressure (CNP) were performed. Results: The results revealed that the passing rate of full masks was higher compared to half masks. Specifically, the passing rate for the half masks and the full masks were 84.7 and 91.6%, respectively. Gender exerted a statistically significant effect on the passing rate. Nevertheless, age, educational background, and training exhibited relatively negligible effects. Certain movements, such as facing forward, were identified as key actions with strong correlation. Additionally, talking was considered a key action with a high failure rate due to instantaneous leakages. Most participants failed at the initial step of CNP, but nearly all of them passed the fit test using CNC. Discussion: Therefore, putting on full masks, especially for women, provides optimal protection during work. Furthermore, attention should be given to the displacement and deformation of the respirator during the key actions. When it comes to fit test methods, CNC was found to be more practical and comprehensive compared to CNP. Moreover, additional physiological characteristics, such as double chins, could be explored as potential influential factors.

Added Breathing Resistance during Exercise Impairs Pulmonary Ventilation and Exaggerates Exercise-Induced Hypoxemia Leading to Impaired Aerobic Exercise Performance.

Protective masks impose variable breathing resistance (BR) on the wearer and may adversely affect exercise performance, yet existing literature shows inconsistent results under different types of masks and metabolic demands. The present study was undertaken to determine whether added BR impairs cardiopulmonary function and aerobic performance during exercise. Sixteen young healthy men completed a graded exercise test on a cycle ergometer under the four conditions of BR using a customized breathing resistor at no breathing resistance (CON), 18.9 (BR1), 22.2 (BR2), and 29.9 Pa (BR3). The results showed that BR significantly elevates respiratory pressure (p < 0.001) and impairs ventilatory response to graded exercise (reduced VE; p < 0.001) at a greater degree with an increased level of BR which caused mild to moderate exercise-induced hypoxemia (final mean SpO2: CON = 95.6%, BR1 = 94.4%, BR2 = 91.6%, and BR3 = 90.6%; p < 0.001). Especially, such a marked reduction in SpO2 was significantly correlated with maximal oxygen consumption at the volitional fatigue (r = 0.98, p < 0.001) together with exaggerated exertion and breathing discomfort (p < 0.001). In conclusion, added BR commonly experienced when wearing tight-fitting facemasks and/or respirators could significantly impair cardiopulmonary function and aerobic performance at a greater degree with an increasing level of BR.

Personal protective equipment implementation in healthcare: A scoping review.

BACKGROUND: Adherence to infection prevention and control (IPC) measures, including the proper use of protective personal equipment (PPE), in health care is complex and is influenced by many factors. Isolated interventions do not have the potential to achieve optimal PPE adherence and appropriate provision, leading to incomplete PPE implementation. OBJECTIVE: To map PPE implementation in health care with a focus on its barriers and facilitators. METHODS: A scoping review was conducted across 14 electronic databases using the Joanna Briggs Institute methodology. RESULTS: Seventy-four papers were included in the review. Findings were analyzed and synthesized into categories to match the Consolidated Framework for Implementation Research domains. The content was then synthesized into barriers for PPE implementation and interventions to address them. The main barriers were discomfort in clinical work; shortage, supply and logistics problems; inadequacies in facilities infrastructure, weakness in policies and communication procedures; and health workers' (HW) psychological issues and lack of preparedness. Implementation interventions reported were related to HW wellbeing assurance; work reorganization; IPC protocols; adoption of strategies to improve communication and HW training; and adoption of structural and organizational changes to improve PPE adherence. CONCLUSIONS: PPE implementation, which is critical IPC programs, involves multilevel transdisciplinary complexity. It relies on the development of context-driven implementation strategies to inform and harmonize IPC policy in collaboration with local and international health bodies.

What We Are Learning from COVID-19 for Respiratory Protection: Contemporary and Emerging Issues.

Infectious respiratory diseases such as the current COVID-19 have caused public health crises and interfered with social activity. Given the complexity of these novel infectious diseases, their dynamic nature, along with rapid changes in social and occupational environments, technology, and means of interpersonal interaction, respiratory protective devices (RPDs) play a crucial role in controlling infection, particularly for viruses like SARS-CoV-2 that have a high transmission rate, strong viability, multiple infection routes and mechanisms, and emerging new variants that could reduce the efficacy of existing vaccines. Evidence of asymptomatic and pre-symptomatic transmissions further highlights the importance of a universal adoption of RPDs. RPDs have substantially improved over the past 100 years due to advances in technology, materials, and medical knowledge. However, several issues still need to be addressed such as engineering performance, comfort, testing standards, compliance monitoring, and regulations, especially considering the recent emergence of pathogens with novel transmission characteristics. In this review, we summarize existing knowledge and understanding on respiratory infectious diseases and their protection, discuss the emerging issues that influence the resulting protective and comfort performance of the RPDs, and provide insights in the identified knowledge gaps and future directions with diverse perspectives.

Safety in the practice of decontaminating filtering facepiece respirators: A systematic review.

BACKGROUND: Considering the new SARS-CoV-2 pandemic and the potential scarcity of material resources, the reuse of personal protective equipment such as filtering facepiece respirators (FFRs) for N95 filtering or higher is being discussed, mainly regarding the effectiveness and safety of cleaning, disinfection and sterilization processes. AIM: To analyze the available evidence in the literature on the safety in processing FFRs. METHODS: A systematic review conducted by searching for studies in the following databases: PubMed, CINAHL, LILACS, CENTRAL, EMBASE, Web of Science, and Scopus. RESULTS: Forty studies were included in this review. The disinfectant/sterilizing agents most frequently tested at different concentrations and exposure periods were ultraviolet irradiation, vaporized hydrogen peroxide and steam sterilization. Microbial reduction was assessed in 21 (52.5%) studies. The only disinfectants/sterilizers that did not caused degradation of the material-integrity were alcohol, electric cooker, ethylene oxide, and peracetic acid fogging. Exposure to ultraviolet irradiation or microwave generated-steam resulted in a nonsignificant reduction in filter performance. CONCLUSION: There is a complex relationship between the FFR raw materials and the cycle conditions of the decontamination methods, evidencing the need for validating FFRs by models and manufacturers, as well as the process. Some methods may require additional tests to demonstrate the safety of FFRs for use due to toxicity.

The effects of face mask specifications on work of breathing and particle filtration efficiency.

The outbreak of the ongoing coronavirus disease 2019 (COVID-19) pandemic has led to the recommended routine use of face masks to reduce exposure risk. In this study, the increase in work of breathing (WOB) imposed by face masks is theoretically studied for both normals and patients with obstructive and restrictive lung diseases at different levels of activity. The results show a significant increase in WOB due to face masks, which is more severe in higher activity levels. The added WOB is considerable during physical activity and may be intolerable for patients with preexisting lung disease and may contribute to inspiratory muscle fatigue and dyspnea. Moreover, in this study, the effects of the physical properties of a fibrous medium, including thickness, porosity, and fiber diameter, are analyzed on the particle filtration efficiency (PFE) and the added WOB. The relations between the physical properties of the fibrous medium and the added WOB and the PFE are shown on some contour plots as a quick and simple tool to select the desired physical properties for a single layer filter to ensure that the added WOB is comfortable while the PFE is sufficiently high.

An Integrated Strategy for the Prevention of SARS-CoV-2 Infection in Healthcare Workers: A Prospective Observational Study.

BACKGROUND: Since the beginning of SARS-CoV-2 outbreak, a large number of infections have been reported among healthcare workers (HCWs). The aim of this study was to investigate the occurrence of SARS-CoV-2 infection among HCWs involved in the first management of infected patients and to describe the measures adopted to prevent the transmission in the hospital. METHODS: This prospective observational study was conducted between February 21 and April 16, 2020, in the Padua University Hospital (north-east Italy). The infection control policy adopted consisted of the following: the creation of the "Advanced Triage" area for the evaluation of SARS-CoV-2 cases, and the implementation of an integrated infection control surveillance system directed to all the healthcare personnel involved in the Advance Triage area. HCWs were regularly tested with nasopharyngeal swabs for SARS-CoV-2; body temperature and suggestive symptoms were evaluated at each duty. Demographic and clinical data of both patients and HCWs were collected and analyzed; HCWs' personal protective equipment (PPE) consumption was also recorded. The efficiency of the control strategy among HCWs was evaluated identifying symptomatic infection (primary endpoint) and asymptomatic infection (secondary endpoint) with confirmed detection of SARS-CoV-2. RESULTS: 7595 patients were evaluated in the Advanced Triage area: 5.2% resulted positive and 72.4% was symptomatic. The HCW team was composed of 60 members. A total of 361 nasopharyngeal swabs were performed on HCWs. All the swabs resulted negative and none of the HCWs reached the primary or the secondary endpoint. CONCLUSIONS: An integrated hospital infection control strategy, consisting of dedicated areas for infected patients, strict measures for PPE use and mass surveillance, is successful to prevent infection among HCWs.

Feasibility Assessment of a New Surveillance Tool for Respiratory Protective Devices Used in U.S. Healthcare.

BACKGROUND: Respiratory protective devices (RPDs) are used for infection prevention in healthcare settings during routine patient care and public health emergencies. In recent years, healthcare systems have experienced shortages of RPDs during outbreaks of infectious diseases, in part due to a lack of information about their availability. New tools to track RPD inventories may improve accessibility during an emergency. Investigators at Vanderbilt University have identified four major themes that influence RPD use for infection prevention: hospital preparedness, responsiveness to airborne pathogens, potential exposure outcomes, and infection control practices related to respirator effectiveness. Based on these findings, an RPD surveillance tool (RST) was developed to collect and share near real-time data about RPD supplies in healthcare facilities. The objective of this study was to conduct a feasibility assessment of this RST. METHODS: The new online surveillance tool was implemented at four large, urban, acute care U.S. hospitals in January 2014; data was collected about RPD inventory, tracking systems, hospital characteristics, and utility of gathered information. RESULTS: The RST was implemented successfully and without difficulty at hospitals that had 78 to 90 percent occupancy rates. Participating hospitals reported that the RST (1) provided value for benchmarking their RPD supply, (2) promoted understanding about RPD accessibility among hospital systems engaged in infection control, and (3) served as a means to assess RPD program quality. CONCLUSION: Implementation of this newly developed RST is feasible and appears to have utility in U.S. hospitals for tracking and understanding RPD use for routine healthcare delivery and public health emergencies.

Pre-World War I Firefighter Respirators and the U.S. Bureau of Mines Involvement in WWI.

The U.S. Bureau of Mines (USBM) was established on July 1, 1910 with a mission to address the previous decade's coal mine fatality incidence rate of greater than 2,000 annually. The need for federal government involvement to assure dependable and safe mine rescue respirators was recognized by the USBM with the first respirator approval being issued in 1919. Prior to this, some occupations exposed individuals to inhalation hazards. Firefighters, in particular, had a critical need of respiratory protection. This article provides a brief summary of pre-World War I (WWI) (1914 to 1918) respiratory protection for firefighters based largely on the work of Bruce J. Held. Also discussed is the then newly established United States Bureau of Mines' (USBM) role with the U.S. War Department during WWI for protection against chemical warfare agents.

Work of Breathing for Respiratory Protective Devices: Method Implementation, Intra-, Inter-Laboratory Variability and Repeatability.

As part of development of performance standards, the International Organization for Standardization (ISO) technical committee, ISO/TC 94/SC 15 Respiratory protective devices (RPD), adopted work of breathing (WOB) to evaluate airflow resistance for all designs (classes) of respiratory protective devices. The interests of the National Institute for Occupational Safety and Health's (NIOSH) National Personal Protective Technology Laboratory (NPPTL) are to compare the proposed WOB method and results for current RPD with those for present resistance methods. The objectives here were to assemble a method to meet the ISO SC15 standards, validate operation and conformance, and assess repeatability of WOB measurements for RPD. WOB method implementation and use followed standards ISO 16900-5:2016 and ISO 16900-12:2016. Volume-averaged total work of breathing (WOBT/VT where VT is tidal volume) determined for standard orifices was analyzed for variation and bias. After fabrication and assembly, the method gave preliminary verification orifice results that met ISO requirements and were equivalent to those from other laboratories. Evaluation of additional results from RPD testing showed tidal volume and frequency determined compliance. Appropriate adjustments reduced average absolute bias to 1.7%. Average coefficient of variation for WOBT/VT was 2.3%. Over 97% of results obtained during significant use over time met specifications. WOBT/VT for as-received air-purifying and supplied-air RPD were repeatable (p<0.05). WOBT/VT for unsealed half mask air-purifying RPD was an average of 31% lower compared to sealed. When experimental parameters were appropriately adjusted, the ISO WOB method implemented by NIOSH NPPTL consistently provided ISO-compliant verification WOBT/VT. Results for appropriately sealed RPD were reproducible.

Lung function and functional capacity among foundry workers using effective risk control measures.

BACKGROUND: Inhaled dust in the environment can trigger specific reactions in the airways and cause various respiratory diseases. OBJECTIVE: Evaluate the lung function and functional capacity of foundry workers who are exposed to metals and use effective control measures. METHOD: A cross-sectional study was realized with 108 workers at a bronze foundry and machining plant and in maintenance at a private university, both in Brazil. The workers were divided into two groups: the study group exposed to metals but using risk control measues and a control group not exposed to metal work. The Medical Research Council Questionnaire on Respiratory Symptoms and the International Physical Activity Questionnaire were administered, and lung function and functional capacity were evaluated. Comparative statistics were used to identify differences in the outcome measures between the two groups. RESULTS: The groups had similar personal and anthropometric characteristics and time on the job. Spirometry and peak expiratory flow presented no significant differences between the groups. And there was also no statistically significant difference between groups in functional capacity as assessed by performance on the six-minute walk test. CONCLUSION: Foundry industry workers in Brazil who were exposed to metal but used risk control measures had similar lung function and functional capacity when compared to the control group who were not exposed to metal. This is a positive results and maybe related to age, time exposure and control of occupational hazards. However, these workers need to continue being monitored in longitudinal studies.

Disinfection of reusable elastomeric respirators by health care workers: a feasibility study and development of standard operating procedures.

BACKGROUND: This was a feasibility study in a Department of Veterans Affairs Medical Center to develop a standard operating procedure (SOP) to be used by health care workers to disinfect reusable elastomeric respirators under pandemic conditions. Registered and licensed practical nurses, nurse practitioners, aides, clinical technicians, and physicians took part in the study. METHODS: Health care worker volunteers were provided with manufacturers' cleaning and disinfection instructions and all necessary supplies. They were observed and filmed. SOPs were developed, based on these observations, and tested on naïve volunteer health care workers. Error rates using manufacturers' instructions and SOPs were compared. RESULTS: When using respirator manufacturers' cleaning and disinfection instructions, without specific training or supervision, all subjects made multiple errors. When using the SOPs developed in the study, without specific training or guidance, naïve health care workers disinfected respirators with zero errors. CONCLUSION: Reusable facial protective equipment may be disinfected by health care workers with minimal training using SOPs.