N95 Respirators Research Articles

Impacts of indoor masks wearing on air contamination during 10-minute speaking in patients with SARS-CoV-2 omicron variant infection.

In 10-minute speaking, N95 respirators significantly decreased SARS-CoV-2 emissions compared with no-mask wearing. However, SARS-CoV-2 was detected in the air even when wearing N95 and surgical masks in patients with high viral loads. Therefore, universal masking of infected and uninfected persons is important for preventing COVID-19 transmission via the air.

Ten questions concerning particle exposure in open electrosurgery and its control strategies

The increasing use of high-frequency electrosurgical pencils in open surgeries has heightened concerns about the adverse implications of electrosurgical smoke (ES) on perioperative personnel. Since 2015, there has been an increasing amount of research on electrosurgical smoke particles annually. Despite data discrepancies, nanoparticles (core particle size <200 nm) generally dominate in number distributions. Particulate matter (PM) concentration is closely related to the type of target tissue. Most studies show that ultrafine particle (UFP) concentrations near the main surgeon’s breathing zone inversely correlate with operating room air changes and positively correlate with the power of the electrosurgical pencil. Local smoke evacuation devices with negative ions, specialized filters and N95 respirators are more effective in protecting perioperative staff health, particularly against UFPs. The objective is to summarize particle exposure knowledge in open electrosurgery and establish a research agenda to protect medical personnel from ES exposure.

Fit Testing Failure of Reprocessed "Duckbill"-Type N95 Masks.

In response to worldwide shortages of N95 masks during the severe acute respiratory syndrome-coronavirus-2 pandemic, various strategies have been used. The Centers for Disease Control and Prevention recommend several strategies, including simple isolation to reprocessing methods using vaporized hydrogen peroxide to guide reuse of masks up to five times. National Institute for Occupational Safety and Health (NIOSH) quantitative fit testing was performed after five trials of donning and doffing in one cohort of new masks and two cohorts of repeatedly sterilized "duckbill"-type N95 masks. One cohort of new masks and two cohorts of sterilized masks were repeatedly subjected to 35% vaporized hydrogen peroxide for either five or 10 cycles. Then, they were subjected to five trials of donning and doffing, with NIOSH quantitative fit testing performed after each wear cycle to assess for any degradation on fit performance caused by sterilization and/or repeated donning and doffing up to the recommended Centers for Disease Control and Prevention limit of five times. All of the fit testing was performed on a single volunteer. The means and 95% confidence intervals for each cohort and the individual results for each mask within each cohort were reported. A χ2 analysis showed significant differences in percentages of masks that pass fit testing in both recycled mask cohorts. These data show the variability of NIOSH fit testing results of both new and sterilized masks. The mask recycling program of our partner health systems thus discarded these types of masks due to the variable failure rate. Health systems should consider individual evaluation to inform their overall policies on mask reuse and recycling.

Efficacy and feasibility of a novel semi-facial respirator with chitosan nanoparticles on the incidence of SARS-CoV-2 infection in healthcare professionals: randomized controlled trial

BackgroundEvidence suggests that semi-facial respirators provide protection against contamination in high-risk environments, although the COVID-19 pandemic called for greater protection and viral inactivation capacity. Thus, the aim of this study was to investigate the efficacy of a novel semi-facial respirator containing chitosan nanoparticles, compared with a conventional N95 respirator on the incidence of laboratory-confirmed SARS-CoV-2 in healthcare professionals. The secondary outcomes were influenza infection, usability and comfort.MethodsRandomized controlled trial within a large public hospital (reference for COVID-19 patients) carried out between March 2021 and June 2023. We included 230 healthcare professionals exposed to SARS-Cov-2 and influenza, working in emergency departments, hospital wards, and intensive care units. Participants were assessed at baseline, after 10 days, and 21 days of follow-up. Researchers, participants, and outcome assessors were blinded to the allocated groups. Outcomes were analyzed by bivariate and multivariate comparisons using logistic regression. Crude (cOR) and adjusted odds ratios (aOR) were estimated, followed by 95% confidence intervals (CIs 95%). We adopted intention-to-treat (ITT) and complete-case (CC) analyses.ResultsBaseline characteristics were considered homogeneous between groups, and usability and comfort were reported as excellent in both groups. Non-significant differences were found for all outcomes, both in the ITT and CC analyses. The incidence of COVID-19 and influenza were, respectively, cOR: 0.96 [CI95%: 0.21–4.42] and cOR: 1.25 [CI95%: 0.34–4.62]; and aOR: 1.08 [CI95%: 0.21–5.47] and aOR: 1.11 [CI95%: 0.17–7.01].ConclusionsWe found that the incidence of SARS-Cov-2 and influenza infections were similar between the new respirator compared to the conventional respirator. Furthermore, we observed that usability and comfort were similar and considered excellent for both respirators.Trial registrationClinicaltrials.gov (NCT04490200, 29/07/2020).

A retrospective characterization of pediatric facemasks marketed in the United States and implications for future designs

Background Device manufacturers who seek to market their pediatric facemasks in the United States (U.S.), as part of anthropometric data requirement, need to demonstrate their mask designs are expected to fit the intended user population. However, currently there are no well accepted test methodologies for pediatric facemasks. In addition, unlike N95 respirators, the expected maximum flow rate, and the pressure drop at that expected maximum flow rate for pediatric facemasks have not been established. Method The objective of this article is three-fold; use a literature survey to determine the worst-case flow rate, and an acceptable breathing resistance; and come up with a bench-test based protocol for assessing fit of pediatric facemasks. Results &amp; discussion The worst-case breathing flow rate for mask testing in the pediatric population is 45–60 Liters/minute (LPM), and the acceptable pressure drop at the worst-case flow rate is 2.0 mmH2O. A retrospective assessment of all the four brands of legally marketed facemasks in the U.S. that could be purchased, revealed that majority of the brands have high filtration efficiency (&gt;95%) at low flow rate 5 LPM which reduces to ~ 80% at 45 LPM. At 5 LPM, the pressure drop ranges from 0.3–0.6 mmH2O, remaining below the 2.0 mmH2O. However, at higher flow rates, (representing strenuous activities, or older children (&gt; 12 years)), most masks exhibited a pressure drop within the range of 2.9 to 6.0 mmH2O. Furthermore, opening the pleats of the facemasks completely results in a notable reduction in pressure drop (a 6.6-fold decrease, p = 0.03). To assess fit of these same brands of facemasks, we then updated our previous validated adult manikin fit-test method and used it in manikins in the age group of 2 to 14 years. Either poor nose-clip adherence to the manikin, low filtration efficiency of the pediatric facemasks, or off-label use (i.e. when donned on manikins representing 2 years to 14 years) contributed to low fit. Conclusions A new bench-top tool to evaluate quantitative fit of pediatric facemasks was developed. In addition, based on the research reported here, we provide practical implications for the members of the community: users, academia and medical device manufacturers.

Total outward leakage of face-worn products used by the general public for source control

During Coronavirus disease 2019 pandemic, the general public used any face-worn products they could get to overcome the shortage of N95 respirators and surgical masks. These products, often not meeting any standards, raised concerns about their effectiveness in reducing the spread of respiratory viruses. This study quantified total outward leakage (TOL) of units from 9 face-worn product categories used by members of the general public. A benchtop system was devised to test 2 units from each category on 2 different-sized headforms with silicone elastomer skin. Each unit was donned 5 times per headform. Both face-worn product category and headform size significantly affected TOL (Pvalue < .05). The TOL of tested face-worn products varied from 10% to 58% depending on both model and headform size. Face-worn products donned on the medium headform had a higher mean TOL compared to those donned on the larger headform. Overall, single-layer cloth masks are the least effective measure for source control due to their highest TOL among the tested face-worn products. Three-layer disposable face masks may be a favorable option for source control among the public. A standard should be developed for face-worn product design and manufacturing to accommodate different facial sizes.

Functionalized N95 Face Mask with a Chemical-Free Paper-Based Collector for Exhaled Breath Analysis: SARS-CoV-2 Detection with a Printed Immunosensor as a Case Study.

Exhaled breath electrochemical sensing is a promising biomedical technology owing to its portability, painlessness, cost-effectiveness, and user-friendliness. Here, we present a novel approach for target analysis in exhaled breath by integrating a comfortable paper-based collector into an N95 face mask, providing a universal solution for analyzing several biomarkers. As a model analyte, we detected SARS-CoV-2 spike protein from the exhaled breath by sampling the target analyte into the collector, followed by its detection out of the N95 face mask using a magnetic bead-based electrochemical immunosensor. This approach was designed to avoid any contact between humans and the chemicals. To simulate human exhaled breath, untreated saliva samples were nebulized on the paper collector, revealing a detection limit of 1 ng/mL and a wide linear range of 3.7-10,000 ng/mL. Additionally, the developed immunosensor exhibited high selectivity toward the SARS-CoV-2 spike protein, compared to other airborne microorganisms, and the SARS-CoV-2 nucleocapsid protein. Accuracy assessments were conducted by analyzing the simulated breath samples spiked with varying concentrations of SARS-CoV-2 spike protein, resulting in satisfactory recovery values (ranging from 97 ± 4 to 118 ± 1%). Finally, the paper-based hybrid immunosensor was successfully applied for the detection of SARS-CoV-2 in real human exhaled breath samples. The position of the collector in the N95 mask was evaluated as well as the ability of this paper-based analytical tool to identify the positive patient.

Modeling Nursing Home Harms From COVID-19 Staff Furlough Policies

Current guidance to furlough health care staff with mild COVID-19 illness may prevent the spread of COVID-19 but may worsen nursing home staffing shortages as well as health outcomes that are unrelated to COVID-19. To compare COVID-19-related with non-COVID-19-related harms associated with allowing staff who are mildly ill with COVID-19 to work while masked. This modeling study, conducted from November 2023 to June 2024, used an agent-based model representing a 100-bed nursing home and its residents, staff, and their interactions; care tasks; and resident and staff health outcomes to simulate the impact of different COVID-19 furlough policies over 1 postpandemic year. Simulating increasing proportions of staff who are mildly ill and are allowed to work while wearing N95 respirators under various vaccination coverage, SARS-CoV-2 transmissibility and severity, and masking adherence. The main outcomes were staff and resident COVID-19 cases, staff furlough days, missed care tasks, nursing home resident hospitalizations (related and unrelated to COVID-19), deaths, and costs. In the absence of SARS-CoV-2 infection in the study's 100-bed agent-based model, nursing home understaffing resulted in an annual mean (SD) 93.7 (0.7) missed care tasks daily (22.1%), 38.0 (7.6) resident hospitalizations (5.2%), 4.6 (2.2) deaths (0.6%), and 39.7 (19.8) quality-adjusted life years lost from non-COVID-19-related harms, costing $1 071 950 ($217 200) from the Centers for Medicare & Medicaid Services (CMS) perspective and $1 112 800 ($225 450) from the societal perspective. Under the SARS-CoV-2 Omicron variant conditions from 2023 to 2024, furloughing all staff who tested positive for SARS-CoV-2 was associated with a mean (SD) 326.5 (69.1) annual furlough days and 649.5 (95% CI, 593.4-705.6) additional missed care tasks, resulting in 4.3 (95% CI, 2.9-5.9) non-COVID-19-related resident hospitalizations and 0.7 (95% CI, 0.2-1.1) deaths, costing an additional $247 090 (95% CI, $203 160-$291 020) from the CMS perspective and $405 250 (95% CI, $358 550-$451 950) from the societal perspective. Allowing 75% of staff who were mildly ill to work while masked was associated with 5 additional staff and 5 additional resident COVID-19 cases without added COVID-19-related hospitalizations but mitigated staffing shortages, with 475.9 additional care tasks being performed annually, 3.5 fewer non-COVID-19-related hospitalizations, and 0.4 fewer non-COVID-19-related deaths. Allowing staff who were mildly ill to work ultimately saved an annual mean $85 470 (95% CI, $41 210-$129 730) from the CMS perspective and $134 450 (95% CI, $86 370-$182 540) from the societal perspective. These results were robust to increased vaccination coverage, increased nursing home transmission, increased importation of COVID-19 from the community, and failure to mask while working ill. In this modeling study of staff COVID-19 furlough policies, allowing nursing home staff to work with mild COVID-19 illness was associated with fewer resident harms from staffing shortages and missed care tasks than harms from increased COVID-19 transmission, ultimately saving substantial direct medical and societal costs.

Assessing the health risks of dermal exposure to heavy metals dust among nail salon technicians.

Nail salon technicians are susceptible to potential exposure to a diverse array of hazardous chemicals in the form of dust or vapors. One of the main routes of exposure is dermal contact. The aim of present study was to health risk assessment of dermal exposure to dust containing heavy metals in nail salon technicians. Dust sampling was done on the work surface of 20 available nail salon technicians. The concentration of five metals including cadmium, lead, chromium, nickel, and manganese were determined using ICP-MS. Afterwards, the United States Environmental Protection Agency (USEPA) guideline was used to estimate the potential health risks, including carcinogenic and non-carcinogenic risks, associated with the analyzed metals. Results indicated the mean concentrations of Pb, Cd, Ni, Cr and Mn were 0.7953±0.4373, 0.0952±0.0264, 0.7666±0.8629, 0.4900±0.5994 and 1.134±0.4736, respectively. The hazard quotient (HQ) of all metals was within the permissible value, while hazard index (HI) was greater than 1. The probability of cancer risk (CR) resulting from dermal exposure to Ni, Cd and Cr exceeded the acceptable risk levels (10-6-10-4), but CR calculated for Pb was less than allowable value. Implementation of engineering controls such as downdraft vented nail tables and portable source capture systems is necessary. Besides, the use of personal protective equipment such as disposable nitrile gloves, N95 respirator masks, and ensuring proper training on safe work practices is recommended.

THE USE OF PERSONAL PROTECTIVE EQUIPMENT BY PHARMACISTS AND RADIOGRAPHERS DURING THE COVID-19 PANDEMIC IN KENDAL DISTRICT

In order to control the transmission of covid-19 which entered Indonesia in early 2020, the government implemented health protocol regulations. Apart from health protocols, one of the steps that health workers can implement to control the transmission of covid-19 when providing services during the pandemic is to use personal protective equipment while working. This is the background for the author to study further in research that aims to determine the use of personal protective equipment used by pharmacists and radiographers during the covid-19 pandemic while in service in Kendal District. The research method used was descriptive qualitative by giving questionnaires electronically using google form to research respondents. The research results obtained include, the majority of respondents were female with a percentage of 62%, the health workers who participated as research respondents consisted of 38% pharmacists and 62% radiographers. The use of personal protective equipment used by pharmacists during the covid-19 pandemic includes masks and gloves which are adjusted to the risks of the work activities carried out. The use of personal protective equipment used by radiographers during the covid-19 pandemic includes wearing work clothes according to hospital regulations, surgical isolation gowns, N95 respirators, eye protection, medical gloves, closed shoes, face shields when carrying out medical interventions and tools additional personal protection according to the risks of the work activities carried out. So, it can be concluded that the personal protective equipment used by pharmacists and radiographers in Kendal District while on duty during the covid-19 pandemic has met the elements of compliance requirements in efforts to control the transmission of covid-19, such as the use of personal protective equipment based on indications for their use by considering the risk of exposure and possible transmission dynamics. By implementing appropriate personal protective equipment when working, it is hoped that pharmacists and radiographers in Kendal District can be protected from transmission of covid-19.

Admission screening testing of patients and staff N95 respirators are cost-effective in reducing COVID-19 hospital-acquired infections

Coronavirus disease 2019 (COVID-19) outbreaks in acute care settings can have severe consequences for patients due to their underlying vulnerabilities, and can be costly due to additional patient bed-days and the need to replace isolating staff. This study assessed the cost-effectiveness of clinical staff N95 respirators and admission screening testing of patients to reduce COVID-19 hospital-acquired infections. An agent-based model was calibrated to data on 178 outbreaks in acute care settings in Victoria, Australia between October 2021 and July 2023. Outbreaks were simulated under different combinations of staff masking (surgical, N95) and patient admission screening testing [none, rapid antigen test (RAT), polymerase chain reaction]. For each scenario, average diagnoses, COVID-19 deaths, quality-adjusted life years from discharged patients, and costs (masks, testing, patient COVID-19 bed-days, staff replacement costs while isolating) from acute COVID-19 were estimated over a 12-month period. Compared with no admission screening testing and staff surgical masks, all scenarios were cost saving with health gains. Staff N95 respirators+ RAT admission screening of patients was the cheapest scenario, saving A$78.4M [95% uncertainty interval (UI) 44.4M-135.3M] and preventing 1543 (95% UI 1070-2146) deaths state-wide per annum. Both interventions were individually beneficial: staff N95 respirators saved A$54.7M and 854 deaths state-wide per annum, while RAT admission screening of patients saved A$57.6M and 1176 deaths state-wide per annum. In acute care settings, staff N95 respirators and admission screening testing of patients can reduce hospital-acquired COVID-19 and COVID-19 deaths, and are cost saving because of reduced patient bed-days and staff replacement needs.

Variation in the fitted filtration efficiency of disposable face masks by sex.

Disposable face masks are a primary protective measure against the adverse health effects of exposure to infectious and toxic aerosols such as airborne viruses and particulate air pollutants. While the fit of high efficiency respirators is regulated in occupational settings, relatively little is known about the fitted filtration efficiencies of ear loop style face masks worn by the public. We measured the variation in fitted filtration efficiency (FFE) of four commonly worn disposable face masks, in a cohort of healthy adult participants (N = 100, 50% female, 50% male, average age = 32.3 ± 9.2 years, average BMI = 25.5 ± 3.4) using the U.S. Occupational Safety and Health Administration Quantitative Fit Test, for an N95 (respirator), KN95, surgical, and KF94 masks. The latter three ear loop style masks were additionally tested in a clip-modified condition, tightened using a plastic clip to centrally fasten loops in the back of the head. The findings show that sex is a major determinant of the FFE of KN95, surgical, and KF94 masks. On average, males had an 11% higher FFE relative to females, at baseline testing. We show that a simple modification using an ear loop clip, results in improvements in the average FFE for females but provides comparatively minor changes for males. On average, females had a 20% increased FFE when a clip was worn behind the head, relative to a 6% increase for males. The efficacy of a disposable face mask as protection against air contaminants depends on the efficiency of the mask materials and how well it fits the wearer. We report that the sex of the wearer is a major determinant of the baseline fitted filtration efficiency (FFE) of commonly available ear loop style face masks. In addition, we show that a simple fit modifier, an ear loop clip fastened behind the head, substantially improves baseline FFE for females but produces only minor changes for males. These findings have significant public health implications for the use of face masks as a protective intervention against inhalational exposure to airborne contaminants.

Effects of Mask Usage During the COVID-19 Pandemic on Sign and Symptoms of Temporomandibular Joint Disorder: A Survey Study.

To evaluate possible temporomandibular disorders (TMD) symptoms that may occur due to mask use in dentists during the coronavirus disease-2019 pandemic period and identify potentially effective factors. An online questionnaire consisting of three parts was sent to dentists and clinical dental students. The first part included questions regarding sociodemographic information. In the second part, questions were asked to evaluate stress levels, TMD symptoms, and treatment of TMD, if any, before (T0) and during the pandemic (T1). In the last part, professional mask choice, mask-related parafunctional movements, and breathing patterns while wearing a mask were evaluated. TMD symptoms and stress levels were significantly higher at T1. An increase in mouth breathing and mask-related parafunctional movements was reported during the use of N95 masks compared with daily life in dentists whose professional mask selection was an N95 respirator. The change in temporomandibular joints pain and muscle pain at rest between T0 and T1 was higher in those whose professional mask choice was N95 respirators than in those who chose to wear one surgical mask. The increase in mouth breathing and mask-related parafunctional movements during the use of N95 respirators may increase TMD.

NIoBReTH: A novel integrative paradigm of protection against SARS-CoV-2 and other airborne pathogens with fewer socioeconomic constraints

There is an imperative need of an effective prophylactic strategy to contain or even end the SARS-CoV-2 pandemic, and to protect the human race from further such pandemics. We propose that NIoBReTH, a composite paradigm of Negative air Ions, virus Blockage, Respiratory Treatment with disinfectants, and Hand hygiene, may provide enough protection against infection by SARS-CoV-2 and perhaps other airborne pathogens, with acceptable safety and less restriction on social/economic activities. Compared to traditional paradigms like N95 respirators and strict social distancing or even large-scale lockdown, the new paradigm may be more easily practiced by individuals, and government adoption may be more robust to individual non-compliance.

Physiological Effects and Tolerance of Wearing Surgical and N95 Masks during Sleep in Normal Individuals and Patients with Mild-Moderate Obstructive Sleep Apnea: A Randomized Crossover Trial

BackgroundIn certain situations, masks are worn during sleep to prevent respiratory infections. However, the effects of mask wearing on cardiopulmonary function during sleep are unknown. This study aimed to determine whether wearing masks during sleep has an impact on cardiopulmonary function, including in patients with obstructive sleep apnea. MethodsThis was a prospective, randomized crossover-controlled trial. The effects of wearing surgical masks or N95 respirators on cardiopulmonary function were measured in healthy subjects and patients with mild-moderate obstructive sleep apnea. Sleep breathing parameters were monitored during nocturnal sleep using a sleep monitor, and subjective feelings about mask wearing were assessed using a questionnaire. ResultsWearing masks during sleep at night did not significantly impact sleep breathing parameters. Furthermore, there were no significant differences in heart rate, blood oxygenation, and blood pressure before and after wearing masks. However, wearing masks, especially the N95 mask, had an adverse impact on sleep quality, and masks were found to be subjectively uncomfortable. ConclusionWearing masks during sleep at night does not adversely affect cardiopulmonary function but they can be uncomfortable, especially the N95 mask. Thus, in circumstances where wearing N95 masks during nocturnal sleep proves intolerable, we recommend the use of surgical masks as a more comfortable alternative.

Enhanced personal protective equipment and dental students' experience and quality of a restorative procedure in a simulated clinical setting.

To evaluate the effects of enhanced personal protective equipment (Enhanced_PPE) on student-operator's experience and restorative procedure. Student-operators (N=29 Year 3 dental students) performed Class II composite restorations (SimpliShade, Kerr) in typodont upper molars (OneDental) equipped with N95 respirators, full-face shields, disposable headwear and gowns (Enhanced_PPE) or surgical masks, protective glasses/goggles and non-disposable gowns (Standard_PPE) 2 weeks later. Cavity dimensions were measured on cone beam computed tomography images. The quality of composite restorations was assessed using selected FDI criteria and Vickers hardness. A questionnaire assessed the operators' discomfort, anxiety, confidence, ability to perform, and procedure outcome. Data were analyzed using paired t-test and McNemar test (alpha=0.05). Student-operators experienced greater discomfort and anxiety, reduced confidence and ability to perform, and rated the procedure as less satisfactory with Enhanced_PPE (p<0.05). Differences in proximal box width were marginally significant (Enhanced_PPE 1.8±0.4mm, Standard_PPE 1.6±0.3mm) (p=0.047). Other cavity dimensions were similar between groups (p>0.05) as were restorations regarding surface luster, anatomical form, marginal adaptation, proximal contour, and contact (p>0.05). There were no differences in the hardness of composite restorations (top p=0.349, bottom p=0.334). Enhanced_PPE led to student-operator discomfort, anxiety, and reduced confidence, but did not impact the quality of Class II preparation and composite restorations versus Standard_PPE.

Comparison of the Time-Course and Magnitude of Cardiorespiratory Responses to Superimposed Surgical Masks or N95 Respirators during 20-min Treadmill Walking

Wearing medical barriers has recently expanded from healthcare to public settings, and could increase dead space and facilitate rebreathing of expired air resulting in heat accumulation, hypercapnia, and hypoxia, particularly during physical activity. We recently showed that participants wearing surgical masks (SM) and N95 respirators (N95) over 60-min during seated rest had mild and immediately reversible (a) increases face microclimate temperature, (b) increases in the pressure of end-tidal (PET)CO2, (c) decreases in PETO2, but (d) no differences in peripheral oxygen saturation (SpO2). Previous publications showed conflicting results of superimposed barrier wearing during physical activity, and there are limited studies that assessed face microclimate temperature and end-tidal gases, particularly comparing superimposed SM and N95. We hypothesized that participants wearing SM and N95 will experience mild face microclimate hyperthermia, hypoxia, and hypercapnia during 3mph treadmill walking. Participants (n=18; 8F) randomly wore (a) no barrier (NB), (b) SM or (c) N95 during a 10-min standing baseline, 20-min treadmill walking (3 mph), and a 10-min standing recovery. We continuously measured face microclimate temperature (thermistor), end tidal gases (PETCO2, PETO2; oro-nasal cannula), SpO2 (peripheral pulse oximeter). Average 20-min PETCO2 (higher; p&lt;0.0001, P=0.0001) and PETO2 (lower; P=0.0003, P=0.0178) were significantly from baseline for both SM and N95, respectively. The delta between the 20-min average compared to the baseline data was not statistically significant for PETCO2 or PETO2 in all three conditions, except for ΔPETCO2 NB vs. N95 (higher; P=0.0344). Additionally, there was no difference in SpO2 across all barrier conditions during exercise. These mild physiological effects may account for qualitative reports of shortness of breath and increased perceived exertion while wearing barriers during physical activity. However, these effect-magnitudes are not physiologically-meaningful, and are immediately reversed upon cessation of exercise and/or barrier removal. NSERC. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The Impact of Electrocautery Smoke on Surgical Staff and the Efficacy of Normal Surgical Masks Versus N95 Masks.

Electrocautery is a commonly used technique in surgical procedures, generating smoke that poses health risks to surgical staff. This study investigates the comparative efficacy of normal surgical masks versus N95 masks in mitigating the harmful effects of electrocautery smoke. Through a systematic review of literature spanning two decades, we explore the causes and effects of electrocautery smoke exposure, including potential long-term inhalation effects. Our findings highlight significant disparities in the protection offered by different masks and underscore the importance of adequate respiratory protection in surgical settings. In addition, we examine the factors influencing the generation and composition of electrocautery smoke, such as the power settings used, the type of tissue being cauterized, and the duration of the procedure. Furthermore, we discuss the potential health risks associated with long-term exposure to electrocautery smoke, including the possibility of respiratory conditions, cardiovascular effects, and carcinogenicity. Our analysis also addresses the importance of implementing appropriate smoke evacuation systems and optimizing operating room ventilation to minimize the concentration of smoke particles in the surgical environment. Overall, this comprehensive analysis provides valuable insights into the impact of electrocautery smoke in surgical settings and the varying levels of protection offered by different masks.

Trichome-Like Biomimetic Air Filters via Templated Silicone Nanofilaments.

Air pollution threats to human health have increased awareness of the role of filter units in air cleaning applications. As an ideal energy-saving strategy for air filters, the slip effect on nanofiber surfaces can potentially overcome the trade-off between filtration efficiency and pressure drop. However, the potential of the slip effect in nanofibrous structures is significantly limited by the tight nanofiber stacks. In this study, trichome-like biomimetic (TLB) air filters with 3D-templated silicone nanofilaments (average diameter: ≈74 nm) are prepared based on an in situ chemical vapor deposition (CVD) method inspired by plant purification. Theoretical modeling and experimental results indicate that TLB air filters make significant use of the slip effect to overcome the efficiency-resistance tradeoff. The selectable filter class (up to U15, ≈99.9995%) allows TLB air filters to meet various requirements, and their integral filtration performance surpasses that of most commodity air filters, including melt-blown cloth, ePTFE membranes, electrospun mats, and glass fiber paper. The proposed strategy directly transforms commercial filter media and filters into TLB air filters using a bottom-up, one-step approach. As a proof-of-concept, reusable N95 respirators and air purifiers equipped with TLB air filters are fabricated, overcoming the limitations of existing filter designs and fabrication methods.

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.