Use Of Filtering Facepiece Respirators Research Articles

Efficacy of powered air-purifying respirators (PAPRs) for source control of simulated respiratory aerosols

Loose-fitting powered air purifying respirators (PAPRs) are a popular alternative to the use of filtering facepiece respirators for healthcare workers. Although PAPRs protect the wearer from aerosol particles, their ability to block infectious aerosol particles exhaled by the wearer from being released into the environment (called source control) is unclear. The source control performance of four PAPRs with loose-fitting facepieces were tested using a manikin that exhales aerosol particles. The PAPRs were tested by themselves and in combination with a face-worn product intended to provide source control (either a surgical mask or an N95® filtering facepiece respirator.) RESULTS: Two PAPR facepieces with filtration panels significantly reduced the release of exhaled aerosols into the environment, while three facepieces without such panels did not. Wearing a surgical mask or respirator under the facepiece significantly improved the source control performance. Most PAPR facepieces do not block aerosols exhaled by the wearer. Facepieces designed to filter exhaled particles can prevent aerosols from being released into the environment. Wearing a surgical mask or a filtering facepiece respirator under the facepiece can also provide source control, but PAPRs are not typically certified for use with masks and respirators.

Comparison of 2 methods for sterilization of filtering facepiece respirators worn for extended periods during the COVID-19 pandemic: An experimental laboratory study

During the COVID-19 pandemic, there was a shortage of filtering facepiece respirators (FFR), leading to prolonged use and reuse of FFRs. FFRs were collected in 3 hospitals after extended use (up to 15 or 30days). We assessed the physical characteristics and filtration levels of worn FFRs, before sterilization. Respirators that achieved at least 94% filtration of aerosol particles, nasal clip still attached, had no tears, had preserved elastic bands, and had no dirt were randomized to receive or not receive cleaning before being submitted to hydrogen peroxide plasma gas sterilization. A total of 1,055 FFRs were collected. Over 85% of them exhibited secured nose clips, preserved strap elasticity, and no tears. However, more than 78% of samples contained dirt, leaving only 101 (19.6%) eligible to undergo sterilization. After sterilization, none of the FFRs in either group achieved minimum filtration, although 72% without cleaning and 80% with cleaning had filtration between 90.0% and 93.9%. A large proportion of FFRs were ineligible for sterilization due to factors unrelated to health care (eg, dirt from makeup). Prolonged reuse of FFRs significantly reduced aerosol filtration efficiency. Eligible FFRs did not maintain 94% filtration after sterilization with or without cleaning.

Estimation of Particle Emission Rates and Calculation of Human Dose from Arc Welding and Cutting of Stainless Steel in a Simulated Confined Workspace

The objective of this study was to estimate the particle emission rates, human dose and retention from two arc welding processes and cutting of stainless steel. The two arc welding processes were Shielded Metal Arc Welding (SMAW) and Tungsten Inert Gas (TIG). In a simulated confined workspace of experimental chamber under controlled conditions, four different scenarios were considered, including the use of filtering face piece respirator (FFR), leaving or staying in the workspace after the emission. Deposited and retained dose in the respiratory tract was assessed for the different regions of the human respiratory tract using a dosimetry model (ExDoM2). The three investigated processes generated high particle number concentrations ranging from 2.4 to 3.6 × 106 particles/cm3 and were the highest during TIG. Among all three processes, PM10 concentrations from cutting reached the highest levels [11 and 22 (× 103) μg/m3], while SMAW had the highest contribution of fine particles [~ 4.1 (× 103) μg/m3], consisting mostly of PM1–2.5. The examination of different scenarios revealed that there is only a slight difference in respect to deposited dose while staying in the workspace for the entire investigated time period (4 h) with or without use of Filtering Facepiece Respirator (FFR). It would be more beneficial in respect to deposited dose if the exposed subject was not wearing a FFR during the emission process and would leave the polluted workspace immediately after the emission period. In the first two scenarios (staying 4 h in the polluted workspace with and without FFR), both welding processes had higher cumulative deposited (~ 23%) and retained dose (~ 20%) in thoracic region compared to cutting (~ 9% and ~ 7%). These results demonstrate that even a short emission period can cause a considerable increase in concentrations of harmful respirable particles, thus increasing the human dose. The approach applied in this study could be used for the determination of personal exposure and dose to particles of known composition particularly in confined workspaces.

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

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. We conducted a prospective study through the Respiratory Protection Program at the Royal Melbourne Hospital from May 2022 to January 2023. Healthcare workers who required respiratory protection and could not shave for religious, cultural, or medical reasons. Online education and personal face-to-face training on the use of FFR with the elastic-band beard cover technique. 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. 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.

Evaluation of Bacterial Contaminants on N95 FFRS after Reuse in Hospital Personnels: A Prospective Study in the Era of COVID-19 Pandemic

Introduction: N95 Filtering Face-piece Respirators (FFRs) prevent the spread of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection and protect medical personnel. It is considered as one of the essential protective equipment. An increased demand for N95 FFRs during the Coronavirus Disease 2019 (COVID-19) pandemic has resulted in shortage crisis for the care of cases arising in hospitals. Therefore, this situation generated the need to implement alternatives like four mask policy that allows reuse of N95 FFRs in settings with limited resources. Aim: To find out the burden of bacterial isolates on N95 FFRs after reuse. Materials and Methods: The present study was a prospective study conducted at Govt. R.D.B.P. Jaipuria hospital, Jaipur, Rajasthan, India, from May 2021 to October 2021 on 526 used N95 FFRs after multiple or extended use by 96 hospital personnel who attended Outpatient Department (OPD) services. Swab samples were collected from both external as well as internal surface of the mask after each use and further subcultured to identify any microorganism present on them. Results: Growth of Gram positive bacilli, and micrococci were found on 499 samples out of total 526 samples. Other bacteria like Pseudomonas spp. and other gram negative were also observed in 19 samples. Furthermore, it was also observed that bacterial load on reused N95 FFRs was mainly commensal flora. Conclusion: Mainly commensal floras were found over internal and external surface of used N95 FFRs. This proves that four mask policy is optimum for judicious use of N95 FFRs and resulted in saving of funds for other more emergency works mainly in OPD settings.

Frenotomy procedure of a cleft lip and palate case

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease can be transmitted through direct or indirect contact with droplets from the infected person’s respiratory system. The aim of this study was a rapid review of the use of personal protective equipment against coronavirus in the field of dentistry.Methods: This study was a rapid cross-sectional review and research. A search was performed in Scopus and PubMed. The key words were PPE) personal protective equipment) with “Corona virus” OR “Coronavirus” OR “Covid 19” as well as thecombination of “oral health” and “dent” with “Corona virus” OR “Covid 19” OR “coronavirus.” Finally, we selected nine articles and excluded 545 irrelevant articles. We reviewed these nine studies in full text and excluded two of them as they were unrelated to the review of personal protective equipment.Results: One study showed that patients with COVID-19 who do not yet have symptoms might seek emergency dental treatment. Two researchers concluded that dentists had good information about how the virus was transmitted but did not know its symptoms well. One study concluded that the use of filtering facepiece respirators (FFRs) during the COVID-19 pandemic is essential to preventing exposure to aerosols and droplets, as it is more fluid-resistant and functions better than surgical masks, which cause flooding around the mouth and nose.Conclusion: This study shows that many dentists do not have enough information about the disease and proper personal protective equipment. This may be due to a lack of precise operating instructions.

Filtering Facepiece Respirator Use in Oral and Maxillofacial Surgery Program Clinics During COVID-19 Peak: A National Survey

The COVID pandemic has caused a shift in the use of filtering facepiece respirators (FFRs) from disposal to reuse when certain criteria are met. However, the use of FFRs by the OMS community and their challenges are not well documented.

Unfolding the effects of decontamination treatments on the structural and functional integrity of N95 respirators via numerical simulations

Filtering facepiece respirators (FFRs) provide effective protection against diseases spread through airborne infectious droplets and particles. The widespread use of FFRs during the COVID-19 pandemic has not only led to supply shortages, but the disposal of single-use facemasks also threatens the environment with a new kind of plastic pollution. While limited reuse of filtering facepiece respirators has been permitted as a crisis capacity strategy, there are currently no standard test methods available for decontamination before their repeated use. The decontamination of respirators can compromise the structural and functional integrity by reducing the filtration efficiency and breathability. Digital segmentation of X-ray microcomputed tomography (microCT) scans of the meltblown nonwoven layers of a specific N95 respirator model (Venus-4400) after treatment with one and five cycles of liquid hydrogen peroxide, ultraviolet radiation, moist heat, and aqueous soap solution enabled us to perform filtration simulations of decontaminated respirators. The computed filtration efficiencies for 0.3 µm particles agreed well with experimental measurements, and the distribution of particle penetration depths was correlated with the structural changes resulting from decontamination. The combination of X-ray microCT imaging with numerical simulations thus provides a strategy for quantitative evaluation of the effectiveness of decontamination treatments for a specific respirator model.

Use of thin silicone dressings for prolonged use of filtering facepiece respirators: Lessons from the universal community testing programme during the COVID-19.

A universal community testing programme (UCTP) was initiated by the government of the Hong Kong Special Administrative Region of the People's Republic of China, as part of a territory‐wide initiative to enhance the control of the coronavirus disease (COVID‐19) pandemic, to facilitate the early identification of asymptomatic patients in the community‐transmission chain. The authors (who were also engaged in this programme) observed that, at the end of their 6‐hour shift, most of the HCPs sustained medical device‐related pressure injuries (MDRPI), frequently on their faces, over the bridge of their nose, the upper cheeks, above the ears, lower jaws, and chin that caused pain and erythema. In this study, our team examined whether two different types of dressing (light silicone foam dressing and soft silicone perforated tape dressing) applied on the anatomical locations (including the bridge of the nose, upper cheek, above the ears, and lower jaw) would enable the wearer to pass the quantitative respirator fit testing that was conducted using a PortaCount Pro+ Respirator Fit Tester 8038. We also investigated if any skin reactions occurred after the participants worn the respirator with our applied dressing materials for 240 minutes in a safe laboratory setting. Lastly, we collected the qualitative feedback concerning how the participants felt about the performance of our dressing materials in preventing MDRPI associated with the prolonged use of tight‐fitting FFRs. A small convenience sample of HCPs (n = 24) who participated in the UCTP was recruited. We randomly selected 12 participants for one type of dressing, and the rest for the second type of dressing. Quantitative fit testing showed an adequate seal of the respirators with the use of both types of thin dressings that were available in the clinical settings. All of the participants except one tolerated the dressings for prolonged use without any report of adverse skin reactions. Our findings may move a step forward in assisting the process of developing feasible pre‐emptive skincare practice guidelines to reduce MDRPI during the prolonged use of nanofiber bacterial surgical respirators.

Sensorized Facemask With Moisture-Sensitive RFID Antenna.

Due to the ongoing COVID-19 pandemic, the use of filtering facepiece respirators (FFRs) is increasingly widespread. Since the masks' wetness can reduce its filtering capabilities, the World Health Organization advises to replace the FFRs if they become too damp, but currently, there is no practical way to monitor the masks' wetness. A low-cost moisture sensor placed inside the FFRs could discriminate a slightly damp mask from a wet one, which must be replaced. In this letter, a radio frequency identification (RFID) tag exploiting an auto-tuning microchip for humidity sensing is designed and tested during an ordinary working day and a physical exercise. The tag returns about 1unit of the digital metric every 3mg of water generated by breathing and sweating, and it can identify excessively wet masks from commonly used ones.

Physiological Effects of N95 FFP and PPE in Healthcare Workers in COVID Intensive Care Unit: A Prospective Cohort Study.

BackgroundHealthcare workers (HCWs) are at increased risk of exposure to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Personal protective equipment (PPE) is mandated for HCWs. However, the physiological effects on the HCWs while working in the protective gear remains unexplored. This study aimed to assess the physiological effects of the prolonged use of PPE on HCWs.Materials and methodsSeventy-five HCWs, aged 18–50 years were enrolled in this prospective, observational, cohort study. The physiological variables [heart rate, oxygen saturation, and perfusion index (PI)] were recorded at the start of duty, 4 hours after wearing N95 filtering facepiece respirator (FFR), pre-donning, and post-doffing. The rating of perceived exertion (RPE) score and modified Borg scale for dyspnea was evaluated. The physiological variables were represented as the mean ± standard deviation. Wilcoxon signed-rank test was used to show any difference in RPE and modified Borg scale for dyspnea. A p value of <0.05 was considered significant.ResultsThere is a statistically significant difference in the physiological parameters post-doffing compared with baseline: Heart rate (p < 0.001); oxygen saturation (p < 0.001); PI (p < 0.001). RPE score showed increased discomfort with continuous use of N95 FFR. However, exertion increased only marginally. The major adverse effects noted with PPE use were fogging, headache, tiredness, difficulty in breathing, and mask soakage, with a resultant mean duration of donning to be 3.1 hours.ConclusionThe use of PPE can result in considerable changes in the physiological variables of healthy HCWs. The side effects may lead to excessive exhaustion and increased tiredness after prolonged shifts in the intensive care unit (ICU) while wearing PPE.How to cite this articleChoudhury A, Singh M, Khurana DK, Mustafi SM, Ganapathy U, Kumar A, et al. Physiological Effects of N95 FFP and PPE in Healthcare Workers in COVID Intensive Care Unit: A Prospective Cohort Study. Indian J Crit Care Med 2020;24(12):1169–1173.

How Effective Is the Filtration of 'KN95' Filtering Facepiece Respirators During the COVID-19 Pandemic?

ObjectivesThe high demand of filtering facepiece respirators (FFRs) worldwide during the period of the COVID-19 pandemic has led to a critical situation for decision-makers regarding their supply. After authorizing the use of FFRs certified by other regions of the world, decision-makers in many countries have published alerts, particularly concerning the ‘KN95’ type.MethodsThis paper investigated the filtration performance of different FFRs using an experimental setup already employed during several studies on FFRs filtration performance. Its high-resolution measuring devices permit to determine filtration performance according to the normative criteria: the pressure drop and the filtration efficiency. Eight different FFRs have been used: four NIOSH-approved FFRs and four not NIOSH-approved with a ‘KN95’ shape available during the beginning of the COVID-19 pandemic.ResultsThe data show a high disparity between different FFRs purchased by healthcare establishments, and between those that are NIOSH-approved and those that are not NIOSH-approved. The results confirm that the NIOSH certification offers good protection according to the normative criteria. The ‘KN95’ types present pressure drops which correspond to the normative value, however their efficiencies are lower than the efficiencies of FFRs certified by NIOSH and lower than 95% at the most penetrate particle size.ConclusionsFFRs marking is not sufficient to conclude on the FFRs’ efficiency. Visual inspection can not determine which samples are counterfeit or have manufacturing defects.

N95 Filtering Facepiece Respirator Use during Pregnancy: A Systematic Review.

Objective This study was aimed to systematically review the use of filtering facepiece respirators, such asN95 masks, during pregnancy. Study Design A comprehensive search for primary literature using Medline, Embase, Scopus, Web of Science, and ClinicalTrials.gov was conducted from inception until April 2020 to find articles reporting outcomes of pregnant women using filtering facepiece respirator (FFR). Studies were selected if they included the use of FFR in pregnant women and reported an outcome of interest including physiologic changes (heart rate, respiratory rate, pulse oximetry, and fetal heart rate tracing) or subjective measures (thermal or exertional discomfort or fit). The Newcastle-Ottawa Quality Assessment scale was used to assess the risk of bias. The main outcome was to describe the physiologic changes in pregnant women compared with nonpregnant women. Due to the small number of studies and heterogeneity of reported outcomes a meta-analysis was not conducted. Results of the studies were synthesized into a summary of evidence table. Results We identified four studies, three cohort studies and one crossover study, comprising 42 women using FFR during pregnancy. Risk of bias was judged to be low. Studies were consistent in showing no significant increase in maternal heart rate, respiratory rate, oxygen saturation, and fetal heart rate between pregnant and nonpregnant women using N95 FFRs for short durations. Repeat fit testing was not supported for women gaining the recommended amount of weight during pregnancy. No evidence was found to reach conclusions about prolonged N95 FFR use in pregnancy. Conclusion Limited duration N95 FFR use during pregnancy is unlikely to impart risk to the pregnant women or her fetus. Key Points Limited N95 use unlikely to impart risk to pregnant woman/fetus.Prolonged N95 use in pregnancy is unstudied.Repeat fit testing in pregnancy likely unnecessary.

Limited Reuse and Extended Use of Filtering Facepiece Respirators

ObjetivoLos equipos de protección individual (EPI), y dentro de ellos las mascarillas, son fundamentales en una pandemia como la del COVID-19, que ha requerido, en muchas ocasiones, de reutilización de material debido a su escasez. El objetivo de esta revisión es sintetizar la evidencia disponible sobre la reutilización y uso extendido de las mascarillas de media y alta filtración.MétodoRevisión exploratoria. Búsqueda a través de lenguaje natural en PubMed y Centros, Agencias y Organizaciones para el Control de Enfermedades. Se limitó a artículos publicados entre 2010-2020 en inglés y en español.ResultadosSe localizaron 83 artículos, seleccionándose 14, más cinco recomendaciones. Los temas abordados se clasifican en siete apartados: Caducidad, uso extendido y reutilización de mascarillas, técnica de manipulación, sellado, efectos físicos psicológicos y cumplimentación, contaminación y descontaminación de mascarillas.ConclusionesLa reutilización de las mascarillas no está recomendada por los organismos oficiales ni los fabricantes, sólo se acepta en casos extraordinarios, como las pandemias. Los estudios se caracterizan por contar con muestras pequeñas, usan diferentes modelos de mascarillas ajustando su recomendación al modelo.

Survival of Microorganisms on Filtering Respiratory Protective Devices Used at Agricultural Facilities.

Bioaerosol is a threat at workplaces, therefore the selection and safe use of filtering facepiece respirators (FFRs) is important in preventive activities. The aim of the study was to assess the survival of microorganisms on materials used for FFRs construction. The parameters for microorganism growth under model conditions were described using the Gompertz equation, model verification was also carried out using FFRs at the farmers’ workplaces. We found that the factors determining a high survival of microorganisms were as follows: moisture corresponding to the conditions of use and storage of FFRs at workplaces, the presence of sweat and organic dust; inorganic dust and addition of biocide in nonwovens limited the growth of microorganisms, resulting in a shortening of the stationary growth phase and decreased cell numbers (5–6 log). Dust concentration at workplaces was higher than EU occupational exposure limit values and WHO recommendations for airborne particulate matter. Microbial contaminations of the air (103–104 CFU/m3), settled dust (104–106 CFU/g) and FFRs (105 CFU/4cm2) during the grain harvest were high, the main contamination being bacteria (actinomycetes, Pseudomonas fluorescens) and xerophilic fungi. A high correlation was found between the number of microorganisms and the weight of dust on FFRs (R2 = 0.93–0.96).

Health care workers' reported discomfort while wearing filtering face-piece respirators.

Filtering face-piece respirators (FFRs) are one method of protecting health care workers from airborne particles; however,research suggests adherence is poor, perhaps due to worker discomfort. Three separate focus groups were conducted at two Veterans Affairs health care facilities. Seventeen health care workers who reported using FFRs as part of their job duties were in the focus groups. Focus group transcripts were coded using qualitative descriptive coding techniques. Participants described experiences of discomfort and physical mask features they believed ,contributed to discomfort. Participants believed FFRs influenced patient care because some patients felt uneasy and changed healthcare workers' behaviors (e.g., doffing procedures, loss of concentration, rushed patient care, and avoidance of patients in isolation resulting from FFR discomfort). Assessment of comfort and tolerability should occur during fit-testing. These factors should also be taken into account by management when training employees on the proper use of FFRs, as well as in future research to improve comfort and tolerability.

Guidance on the use of respiratory and facial protection equipment

Infectious micro-organisms may be transmitted by a variety of routes, and some may be spread by more than one route. Respiratory and facial protection is required for those organisms that are usually transmitted via the droplet/airborne route, or when airborne particles have been artificially created, such as during ‘aerosol-generating procedures’. A range of personal protective equipment that provides different degrees of facial and respiratory protection is available. It is apparent from the recent experiences with severe acute respiratory syndrome and pandemic (H1N1) 2009 influenza that healthcare workers may have difficulty in choosing the correct type of facial and respiratory protection in any given clinical situation. To address this issue, the Scientific Development Committee of the Healthcare Infection Society established a short-life working group to develop guidance. The guidance is based upon a review of the literature, which is published separately, and expert consensus.

Physiological Burden Associated with the Use of Filtering Facepiece Respirators (N95 Masks) during Pregnancy

The purpose of this study was to review the available literature regarding the physiological burden imposed on pregnant women by their wearing filtering facepiece respirators. A medical literature search was conducted using MEDLINE (1996-2008) for English language articles, bibliographies of retrieved articles, electronic references from medical and governmental agency sources, and selected textbook articles. Two hundred thirty-four articles from the medical literature and 267 electronic references were retrieved, of which 51 articles from the medical literature, 25 electronic references, and 2 textbook articles were selected for data acquisition. Very little rigorous scientific data exist on the physiological burden associated with the use of filtering facepiece respirators by pregnant women, and no definitive conclusions can be reached at this time. Although studies are warranted, they may be difficult to undertake because of health concerns and potential liability associated with the use of pregnant women in medical research. Computer modeling that incorporates features of pulmonary function in pregnancy might offer an alternative to human studies. Filtering facepiece respirators developed to meet the respiratory limitations of pregnant wearers might offer a universal design that would improve the comfort and tolerability for all users. Alternative strategies that limit the pregnant woman's contact with potentially infectious agents (e.g., job reassignment, working from home) may have to be employed in certain circumstances.