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.

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

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

Chest compression quality comparing 1-min vs 2-min rotation of rescuers wearing N95 masks.

BACKGROUND: During the COVID-19 pandemic, cardiopulmonary resuscitation (CPR) performed by rescuers wearing well-sealed respirators such as N95 masks, was associated with significant reduction in the chest compression rate and depth. This was attributed to fatigue during the standard 2-min rescuer rotations. We hypothesized that in such situations, rotating rescuers every one minute, instead of the standard two minutes would improve CPR quality. AIM: To compare the quality of chest compressions when rescuers wearing N95 masks are rotated every one minute, instead of the standard practice of two-minute rotations. METHODS: A randomized, controlled, crossover trial was conducted, with the approval of the institutional Ethics Committee. Medical students who volunteered as rescuers were trained to perform high-quality chest compressions on a manikin, and then randomly allocated into pairs. Each pair was randomized to one of two trial groups viz. one-minute rotations crossed-over to two-minute rotations; and vice versa. Thus, each pair performed CPR with one-minute rotations, as well as two-minute rotations Each CPR session included chest compressions for a duration of 12 min. The outcome parameters included CPR quality, compression depth, compression rate, and chest compression fraction. Rescuer fatigue was measured before and after each study session using the modified Borg scale. RESULTS: Fifty-six participants completed the study. The overall CPR quality was statistically similar in the study arms (median 88% vs. 81%, p = 0.09). However, the minute-to-minute inter-arm comparison revealed significantly lower CPR quality in the 2-min rotation arm, at the end of minutes 4, 6, 8, 10 and 12 (respective p-values 0.03, 0.001, 0.008, 0.02, 0.002). A similar trend was observed in compression depth also. Rescuer fatigue score was significantly less with 1-min rotations compared to 2-min rotations (p < 0.001). Rescuer vital signs and cardiorespiratory parameters were not different with the two types of rotations. CONCLUSION: During CPR performed by rescuers wearing N95 masks, the quality of CPR appears to be superior with rescuers rotating at 1-min instead of 2-min intervals. More frequent rotation was also associated with less rescuer fatigue.

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

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

Study on the relationship between the fitness of three types of N95 respirators and facial dimensions.

N95 respirators are the core equipment used by healthcare workers to prevent the spread of respiratory diseases. The protective effect of N95 against infection spread depends on the fit of the N95 to the wearer, which is related to the wearer's facial dimensions. The purpose of this cross-sectional study was to assess the relationship between the fit of three types of N95 and facial dimensions. A total of 305 healthcare workers from ten hospitals in Beijing were recruited for this study. Facial dimensions of workers were measured using Intel RealSense Depth Camera D435. Fit testing was conducted on three types of N95 using the TSI-8038 Porta Count Pro + Respirator Fit Tester. Possible associations between the fit test results and facial dimension data were examined. A Porta Count reading of 100 was used as the criterion for an acceptable fit. The fit of the folding respirators was positively correlated with nose length (r = 0.13, p = 0.02), nose height (r = 0.14, p = 0.02), and face width (r = 0.12, p = 0.03), whereas that of flat respirators was correlated with nose width (r = 0.16, p < 0.01), chin length (r = 0.18, p < 0.01), and pro-face width (r = 0.13, p = 0.02), and that of arched respirators was correlated with the nose length (r = 0.13, p = 0.03). The fit of N95 for wearers depends on their facial features. The results of this study can provide advice for medical workers to choose the appropriate N95. Medical staff should fully consider their facial dimensions when choosing an appropriate N95 to improve the protective efficacy of respirators and to reduce the risk of infection by respiratory diseases.

A comparative study of point-of-care protection from N95 filtering face-piece respirators in a Residential Aged Care Facility and a Tertiary Hospital-Respiratory protection challenges remain amidst long-term impacts of COVID-19.

This study compared the effectiveness of N95 FFRs in providing respiratory protection for healthcare staff in a residential aged care facility (RACF) and tertiary teaching hospital (TTH) who had previously passed their occupational respiratory protection program fit test. A total of 126 healthcare workers who were regularly using N95 FFRs and who had previously passed a fit test participated in this comparative study. In this study, participants were again fit tested with the PortaCount machine, and their self-assessed tolerability of wearing an N95 FFR was assessed using a standardized questionnaire. The main outcome measures included the pass rate of the fit test and the assessment of tolerability and comfort of the N95 FFR. Across all participants, the fit test pass rate was low (27%), indicating persistent gaps in respiratory protection programs for healthcare workers during the ongoing COVID-19 pandemic. Hospital workers were 3.7 times more likely to pass the test compared to their counterparts in RACFs (p < 0.001). It was also found that workers in RACFs reported higher levels of discomfort and overall dissatisfaction with N95 FFRs compared to hospital staff. These findings highlight the need for targeted interventions and improvements in respiratory protection practices beyond annual fit testing, particularly in RACFs, to ensure the safety of healthcare workers and the vulnerable population they serve.

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

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

The effect of mask usage of the health personnel on blood gas analysis and cognitive strengthening during COVID-19 pandemic.

Objectives: To investigate the effect of lengthy mask use on blood gas values and cognitive functions. METHODS: The cross-sectional study was conducted in February and March 2022 at Mersin City Training and Research Hospital, Mersin, Turkey, and comprised healthcare professionals of either gender aged 20-60 years working in the 3rd level intensive care unit. Each volunteer was subjected to venous blood gas analysis at the beginning and end of the 8-hour morning shift. Coronavirus disease-2019 status was noted, and further data related to cognitive functions was collected using a 7-item questionnaire. Data was analysed using SPSS 20. RESULTS: Of the 63 subjects, 43(68.3%) were women and 20(31.7%) were men. The overall mean age was 33.53±6.76 years. There were 42(66.7%) subjects using N95 mask; 27(64.3%) women and 15(35.7%) men with mean age 32.38±6.54 years. There were 21(33.3%) subjects wearing surgical masks; 16(76.2%) women and 5(23.8%) men with mean age 35.95±0.76 years. Intergroup comparisons were non-significant for all the markers (p>0.05). Within the N95 mask group, potential of hydrogen and lactate values were significantly different (p<0.05), while in the surgical mask group, potential of hydrogen and partial pressure of oxygen were significantly different (p<0.05). There were 28(66.7%) subjects in the N95 group who had been affected by coronavirus disease-2019 compared to 16(76.2%) in the surgical mask group (p>0.05). Subjects in the N95 mask group had significant impaired cognitive functions compared to the surgical mask group (p<0.05). Conclusion: Impairment in cognitive functions in intensive care unit workers using masks could be explained by the development of intermittent long-term moderate hypoxia.

Evaluation of eyelid features' changes before and after COVID-19 pandemic amongst healthcare and home office workers.

PURPOSE: To evaluate the eyelid features' changes after N95 face mask (FM) usage in healthcare workers through the new type of Coronavirus Disease 2019 (COVID-19) pandemic and make a comparison with home-office workers as a control group with a computer vision algorithm. MATERIALS AND METHODS: Sixty healthcare workers and forty control participants with similar demographic features included. Standardized biometric photographs which were taken before and after the COVID-19 pandemic, analyzed by the ImageJ program (NIH, Bethesda, Md.) software. The distances between the central light reflex on the cornea and the upper (UE) and lower eyelid (LE) were recorded as the marginal reflex distances. (MRD1, MRD2 respectively) Parameters of pretarsal show (PTS) of UE and brow pupil diameter (BPD) were analyzed for both of the eyes. RESULTS: There were no significant differences among the groups' measurements before the COVID-19 pandemic. In healthcare workers' group after the pandemic, values of MRD1, PTS, BPD showed a significant decrease in their right eye (p = 0.001, p = 0.002, p = 0.001 respectively) and same values reduced in the left eyes as well when compared with pre-pandemic measurements. (p = 0.048, p = 0.001, p = 0.001 respectively) PTS and BPD values were decreased for both right and left eyes of the controls. (p = 0.044, p = 0.001 and p = 0.001, p = 0.001 respectively) MRD1 measurements after the pandemic showed no difference either in the right or left eyes of the control group after the pandemic. (p = 0.071 and p = 0.065 respectively). DISCUSSION: Results showed that both BPD and PTS values decreased independently from the previous FM usage in both of the groups. Even though MRD1 values remained within the normal values, a significant decrease was detected in the healthcare workers group which suggested the cause was newly developed upper eyelid (UE) dermatochalasis after long hours of FM usage. Although it is hard to make a truly objective evaluation both usage of standardized biometric photographs and a computer-based measurement system makes the results reliable.

Impact of COVID-19 vaccination on transmission risk of breakthrough infections: Lessons from adapted N95 mask sampling for emerging variants and interventions.

This study used an adapted N95 mask sampling to understand the effect of COVID-19 vaccination in the context of circulating variants on infected individuals to emit the virus into the air, a key risk factor of transmission. Mask, swab, and blood samples were collected from 92 COVID-19 patients vaccinated (Covishield/COVAXIN-partial/fully) or unvaccinated between July and September 2021 during the Delta-dominated period in Mumbai. Mask/swab samples were analyzed by reverse transcription polymerase chain reaction for viral RNA. Blood was evaluated for SARS-CoV-2 anti-spike and nucleocapsid antibody responses. At <48 h of diagnosis, 93% of the patients emitted detectable viral RNA, with 40% emitting >1000 copies in 30 min (high emitters). About 8% continued to be high emitters even after 8 days of symptom onset. No significant difference was observed in emission patterns between partial, full, and unvaccinated patients. However, when vaccinated patients were stratified based on spike protein neutralization and nucleocapsid immunoglobulin G (IgG), the group with moderate/high neutralization showed a significantly lower proportion of high emitters and viral RNA copies than the group with no/low neutralization, which further reduced in the group having antinucleocapsid IgG. In conclusion, mask sampling showed that Delta infections were associated with greater virus emission in patients, which was significantly reduced only in vaccinated patients with moderate/high SARS-CoV-2 neutralization, especially with evidence of past infection. The study demonstrated that mask sampling could be useful for understanding the transmission risk of emerging variants, screening vaccine/booster candidates, and guiding control interventions.

The Effects of Wearing a 3-Ply or KN95 Face Mask on Cerebral Blood Flow and Oxygenation.

BACKGROUND: The SARS-CoV-2 virus has impacted life in many ways, one change being the use of face masks. Their effect on MRI-based measurements of cerebral oxygen levels with quantitative susceptibility mapping (QSM) and cerebral blood flow (CBF) is not known. PURPOSE: This study investigated whether wearing a face mask leads to changes in CBF and cerebral venous oxygen saturation measured with MRI. STUDY TYPE: Repeated-measures cohort study. POPULATION: A total of 16 healthy volunteers (eight male, eight female; 22-36 years) were recruited for the 3-ply study. Ten of the 16 participants (five male, five female; 23-36 years) took part in the KN95 study. FIELD STRENGTH/SEQUENCE: A 3 T, single-delay 3D gradient-and spin-echo pseudo-continuous arterial spin labeling (pCASL) scan for CBF quantification, and gradient-echo for QSM and oxygenation quantification. ASSESSMENT: Gray matter CBF and magnetic susceptibility were assessed by masking the pCASL CBF map and the QSM map to the T1 -weighted gray matter tissue segmentation. Venous oxygenation was determined from venous segmentation of QSM maximum intensity projections. STATISTICAL TESTS: Paired Student's t-tests and Cohen's d effect sizes were used to compare the face mask and no face mask scans for gray matter CBF, gray matter magnetic susceptibility, and cerebral venous oxygen saturation. Standard t-tests were used to assess whether the order of scanning with and without a mask had any impact. A statistical cut off of P < 0.05 was used. RESULTS: The 3-ply masks increased gray matter CBF from an average of 43.99 mL/(100 g*min) to 46.81 mL/(100 g*min). There were no significant changes in gray matter magnetic susceptibility (P = 0.07), or cerebral venous oxygen saturation (P = 0.36) for the 3-ply data set. The KN95 masks data set showed no statistically significant changes in gray matter CBF (P = 0.52) and magnetic susceptibility (P = 0.97), or cerebral venous oxygen saturation (P = 0.93). DATA CONCLUSION: The changes in blood flow and oxygenation due to face masks are small. Only CBF increased significantly due to wearing a 3-ply mask. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 3.

Bleach Emissions Interact Substantially with Surgical and KN95 Mask Surfaces.

Mask wearing and bleach disinfectants became commonplace during the COVID-19 pandemic. Bleach generates toxic species including hypochlorous acid (HOCl), chlorine (Cl2), and chloramines. Their reaction with organic species can generate additional toxic compounds. To understand interactions between masks and bleach disinfection, bleach was injected into a ventilated chamber containing a manikin with a breathing system and wearing a surgical or KN95 mask. Concentrations inside the chamber and behind the mask were measured by a chemical ionization mass spectrometer (CIMS) and a Vocus proton transfer reaction mass spectrometer (Vocus PTRMS). HOCl, Cl2, and chloramines were observed during disinfection and concentrations inside the chamber are 2-20 times greater than those behind the mask, driven by losses to the mask surface. After bleach injection, many species decay more slowly behind the mask by a factor of 0.5-0.7 as they desorb or form on the mask. Mass transfer modeling confirms the transition of the mask from a sink during disinfection to a source persisting >4 h after disinfection. Humidifying the mask increases reactive formation of chloramines, likely related to uptake of ammonia and HOCl. These experiments indicate that masks are a source of chemical exposure after cleaning events occur.

Effect of Wearing N95 Mask on the Quality of Chest Compressions in Prehospital Emergency Personnel: A Cross-over Study.

OBJECTIVE: To evaluate the effect of wearing an N95 mask on the quality of chest compression and fatigue of prehospital emergency personnel during cardiopulmonary resuscitation (CPR). METHODS: Twenty-four eligible participants were recruited. Participants' age, sex, height, and weight were recorded. After completing the CPR training and examination, participants were tested twice, wearing surgical mask or an N95 mask, while performing chest compressions for 2 minutes. The quality of chest compression (including compression frequency, depth, rebound, and position) was recorded by the simulator. Borg fatigue scores and physiological parameters (including heart rate, mean arterial pressure, pulse oxygen saturation, and respiratory rate) were recorded before and after chest compressions. RESULTS: Compared to wearing surgical masks, participants wearing N95 masks had significantly lower quality of chest compression, including compression frequency (98.3 ± 4.9 bpm vs 104.0 ± 6.0 bpm, P < 0.001), depth (47.1 ± 4.5 mm vs 50.5 ± 5.4 mm, P < 0.001), and rebound (90.2 ± 2.7% vs 94.3 ± 2.1%, P < 0.001). The compression position was not affected. The period data showed that the difference in compression quality started after 1 minute of compressions. Participants wearing N95 masks had higher Borg fatigue scores [6.1(2) vs 5.1(2), P < 0.001], heart rates (121.2 ± 5.7 bpm vs 109.9 ± 6.0 bpm, P < 0.001), mean arterial pressures (106.3 ± 8.0 mmHg vs 99.0 ± 8.5 mmHg, P = 0.012), and respiratory rates (29.5 ± 2.7 bpm vs 24.7 ± 2.5 bpm, P < 0.001). CONCLUSION: This study showed that the use of an N95 mask by prehospital emergency personnel during the performance of chest compressions resulted in a reduction of compression quality and increased clinician fatigue. There is a need for CPR training for medical personnel wearing personal protective equipment.

Medical Masks Versus N95 Respirators for Preventing COVID-19 Among Health Care Workers : A Randomized Trial.

BACKGROUND: It is uncertain if medical masks offer similar protection against COVID-19 compared with N95 respirators. OBJECTIVE: To determine whether medical masks are noninferior to N95 respirators to prevent COVID-19 in health care workers providing routine care. DESIGN: Multicenter, randomized, noninferiority trial. (ClinicalTrials.gov: NCT04296643). SETTING: 29 health care facilities in Canada, Israel, Pakistan, and Egypt from 4 May 2020 to 29 March 2022. PARTICIPANTS: 1009 health care workers who provided direct care to patients with suspected or confirmed COVID-19. INTERVENTION: Use of medical masks versus fit-tested N95 respirators for 10 weeks, plus universal masking, which was the policy implemented at each site. MEASUREMENTS: The primary outcome was confirmed COVID-19 on reverse transcriptase polymerase chain reaction (RT-PCR) test. RESULTS: In the intention-to-treat analysis, RT-PCR-confirmed COVID-19 occurred in 52 of 497 (10.46%) participants in the medical mask group versus 47 of 507 (9.27%) in the N95 respirator group (hazard ratio [HR], 1.14 [95% CI, 0.77 to 1.69]). An unplanned subgroup analysis by country found that in the medical mask group versus the N95 respirator group RT-PCR-confirmed COVID-19 occurred in 8 of 131 (6.11%) versus 3 of 135 (2.22%) in Canada (HR, 2.83 [CI, 0.75 to 10.72]), 6 of 17 (35.29%) versus 4 of 17 (23.53%) in Israel (HR, 1.54 [CI, 0.43 to 5.49]), 3 of 92 (3.26%) versus 2 of 94 (2.13%) in Pakistan (HR, 1.50 [CI, 0.25 to 8.98]), and 35 of 257 (13.62%) versus 38 of 261 (14.56%) in Egypt (HR, 0.95 [CI, 0.60 to 1.50]). There were 47 (10.8%) adverse events related to the intervention reported in the medical mask group and 59 (13.6%) in the N95 respirator group. LIMITATION: Potential acquisition of SARS-CoV-2 through household and community exposure, heterogeneity between countries, uncertainty in the estimates of effect, differences in self-reported adherence, differences in baseline antibodies, and between-country differences in circulating variants and vaccination. CONCLUSION: Among health care workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in hazard of RT-PCR-confirmed COVID-19 for medical masks when compared with HRs of RT-PCR-confirmed COVID-19 for N95 respirators. The subgroup results varied by country, and the overall estimates may not be applicable to individual countries because of treatment effect heterogeneity. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research, World Health Organization, and Juravinski Research Institute.

Effect of an N95 respirator and a surgical mask-covered N95 on the cardiovascular responses of dentists treating paediatric patients: A crossover clinical trial.

BACKGROUND: The studies on cardiovascular alterations when using an N95 respirator or surgical mask-covered N95 during dental treatments are limited. AIM: To investigate and compare the cardiovascular responses of dentists treating paediatric patients while wearing an N95 respirator or a surgical mask-covered N95. DESIGN: This was a crossover clinical trial in 18 healthy dentists wearing an N95 respirator or surgical mask-covered N95 during the dental treatment of paediatric patients. Oxygen saturation (SpO2 ), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were monitored at baseline, intraoperation, and postoperation. The data were analyzed using the generalized estimating equation. RESULTS: The mean SpO2 , HR, SBP, DBP, and MAP significantly changed from baseline up to the end of the procedures after wearing an N95 by 3.1%, 19.3%, 11.5%, 17.7%, and 13.8% and after wearing a surgical mask-covered N95 by 3.0%, 20.2%, 5.3%, 13.9%, and 8.8%, respectively (p < .05). No significant differences in these values were found between groups (p > .05). CONCLUSIONS: N95 respirators and surgical mask-covered N95s significantly impact the cardiovascular responses of dentists treating paediatric patients with no differences between the two types of masks.

Simulated workplace protection factor study of a quarter-facepiece elastomeric respirator.

The assigned protection factor (APF) for quarter-facepiece respirators is currently 5, based on fit test data from the 1970s with models no longer commercially available. The goal of this project was to evaluate the respirator fit capability of a NIOSH-approved N95 quarter-facepiece elastomeric respirator with a gel-based facial seal design (Envo Mask by Sleepnet Corporation). Human subjects were recruited from healthcare and the general population to satisfy a 25-member NIOSH bivariate panel. Subjects were fit tested with a fast fit protocol using a TSI Portacount Model 8038 in the N95 mode. Second-by-second measures of fit were then collected while subjects performed a 30-min series of simulated healthcare activities. Subjects completed a short comfort questionnaire. The median (5th, 95th percentile) fit factor was 188 (48, 201). Simulated workplace protection factors (SWPFs) had a median (5th, 95th percentile) of 181 (94, 199) (data truncated at 200) and 570 (153, 1508) (non-truncated data). Subjects ranked inhalation and exhalation as "easy" with average scores of 5.0/6.0 and 5.2/6.0, respectively. The facepiece was ranked between slightly comfortable and comfortable (4.8/6.0) and the harness as comfortable (5.0/6.0). Most users agreed (5.2/6.0) that the mask was stable on their faces. The 5th percentile SWPF of 95 supports an APF of at least 10 for this quarter-facepiece elastomeric respirator, similar to the APF for half-facepiece respirators. This study supports increasing the APF for quarter-facepiece respirators, a class that has been largely ignored by manufacturers for the past 40 years. A lightweight, low profile, reusable quarter-facepiece respirator is an effective option for healthcare and other worker protection during a pandemic and similar situations.

Validation of N95 respirator models for pressure drop and particle capture efficiency.

Despite efforts to apply administrative and engineering controls to minimize worker exposure to aerosols, filtering facepiece respirators (FFRs) continue to be an important form of personal protective equipment in hard-to-control settings such as healthcare, agriculture, and construction. Optimizing the performance of FFRs can be advanced with the use of mathematical models that incorporate the forces that act on particles during filtration as well as those filter characteristics that influence filter pressure drop. However, a thorough investigation of these forces and characteristics using measurements of currently available FFRs has not been undertaken. Filter characteristics such as fiber diameter and filter depth were measured from samples taken from six currently-available N95 FFRs from three manufacturers. A filtration model was developed that included diffusion, inertial and electrostatic forces to estimate the filtration of an aerosol with a Boltzmann charge distribution. The diameter of the filter fibers was modeled as either a single "effective" diameter or as a lognormal distribution of diameters. Both modeling schemes produced an efficiency curve that simulated efficiency measurements made over a range of particle diameters (0.01 - 0.3 µm) with the use of a scanning mobility particle sizer in the region where efficiency is at a minimum. However, the method using a distribution of fiber diameters produced a better fit for particles > 0.1 µm. The coefficients associated with a simple form of the diffusion equation constituting a power law incorporating the Peclet number were adjusted to enhance model accuracy. Likewise, the fiber charge of the electret fibers was also adjusted to maximize model fit but remained within levels reported by others. A filter pressure drop model was also developed. Results demonstrated the need for a pressure drop model applicable to N95s relative to existing models developed with the use of fibers with larger diameters than those used in current N95 FFRs. A set of N95 FFR characteristics are provided that can be used to develop models of typical N95 FFR filter performance and pressure drop in future studies.

Fit evaluation of NIOSH approved N95 filtering facepiece respirators with various skin protectants: A pilot study.

Widespread disease outbreaks can result in prolonged wear times of National Institute for Occupational Safety and Health Approved N95 filtering facepiece respirators by healthcare personnel. Prolonged wear times of these devices can cause the development of various adverse facial skin conditions. Healthcare personnel have been reported to apply "skin protectants" to the face to reduce the pressure and friction of respirators. Because tight-fitting respirators rely on a good face seal to protect the wearer, it is important to understand if the fit is affected when skin protectants are used. This laboratory pilot study included 10 volunteers who performed quantitative fit tests to evaluate respirator fit while wearing skin protectants. Three N95 filtering facepiece respirator models and three skin protectants were evaluated. Three replicate fit tests were performed for each combination of subject, skin protectant (including a control condition of no protectant), and respirator model. Fit Factor (FF) was affected differently by the combination of the protectant type and respirator model. The main effects of the protectant type and respirator model were both significant (p < 0.001); additionally, their interaction was significant (p = 0.02), indicating FF is affected by the combined effects of the protectant type and respirator model. Compared to the control condition, using a bandage-type or surgical tape skin protectant decreased the odds of passing the fit test. Using a barrier cream skin protectant also decreased the odds of passing the fit test across all models compared to the control condition; however, the probability of passing a fit test was not statistically significantly different from the control condition (p = 0.174). These results imply that all three skin protectants reduced mean fit factors for all N95 filtering facepiece respirator models tested. The bandage-type and surgical tape skin protectants both reduced fit factors and passing rates to a greater degree than the barrier cream. Respirator users should follow respirator manufacturers' guidance on the use of skin protectants. If a skin protectant is to be worn with a tight-fitting respirator, the fit of the respirator should be evaluated with the skin protectant applied before use in the workplace.

Personalized 3D-printed frames to reduce leak from N95 filtering facepiece respirators: A prospective crossover trial in health care workers.

Correctly fitting N95 filtering facepiece respirators (FFRs) have become increasingly important in health care throughout the COVID-19 pandemic. We evaluated the hypothesis that personalized 3D-printed frames could improve N95 FFRs quantitative fit test pass rates and test scores in health care workers (HCWs). HCWs were recruited at a tertiary hospital in Adelaide, Australia (ACTRN 12622000388718). A mobile iPhone camera + app was used to produce 3D scans of volunteers' faces, which were then imported into a software program to produce personalized virtual scaffolds suited to each user's face and their unique anatomical features. These virtual scaffolds were printed on a commercially available 3D printer, producing plastic (and then silicone-coated, biocompatible) frames that can be fitted inside existing hospital supply N95 FFR. The primary endpoint was improved pass rates on quantitative fit testing, comparing participants wearing an N95 FFR alone (control 1) with participants wearing the frame + N95 FFR (intervention 1). The secondary endpoint was the fit factor (FF) in these groups, and R-COMFI respirator comfort and tolerability survey scores. N = 66 HCWs were recruited. The use of intervention 1 increased overall fit test pass rates to 62/66 (93.8%), compared to 27/66 (40.9%) for controls. (OR for pFF pass 20.89 (95%CI: 6.77, 64.48, p < 0.001.) Average FF increased, with the use of intervention 1-179.0 (95%CI: 164.3,193.7), compared to 85.2 (95%CI: 70.4,100.0) with control 1. Pass rates and FF were improved with intervention 1 compared to control 1 for all stages of the fit-test: bending, talking, side-to-side, and up-down motion. (p < 0.001 all stages). Tolerability and comfort of the frame were evaluated with the validated R-COMFI respirator comfort score, showing improvement with the frame compared to N95 FFR alone (p = 0.006). Personalized 3D-printed face frames decrease leakage, improve fit testing pass rates and FF, and provide improved comfort compared to the N95 FFR alone. Personalized 3D-printed face frames represent a rapidly scalable new technology to decrease FFR leakage in HCW and potentially the wider population.

Influence of N95 Mask-related Hypoxemia on Headache, Stress, Anxiety, and Quality of Sleep during COVID-19 Patient Care among Frontline Health Care Professionals.

BACKGROUND: Prolonged use of N95 masks by healthcare workers might affect physical health due to mask-related hypoxia in addition to the psychological effects of N95 masks. We tried to explore the association of N95 mask-related hypoxia and headache with stress, quality of sleep, and anxiety in the current study. MATERIALS AND METHODS: The sample (N = 78) consisted of 41 doctors and 37 nurses involved in COVID-19 patient care and using N95 masks with or without PPE for at least 4 hours. Perceived stress scale (PSS), Coronavirus anxiety scale (CAS), and Pittsburgh sleep quality index (PSQI) were administered, and physical parameters like heart rate and oxygen saturation (SpO2) were measured. RESULTS: Around 42% of the study participants experienced headaches after wearing an N95 mask and had a higher increase in heart rate (mean percent:10.5% vs 6.3%) and decline in SpO2 (mean percent: 2.6% vs 1.5%) compared to those who didn't develop a headache after N95 mask use. Independent samples t-test showed a mean difference for PSS and CAS between those who experienced headaches and those who didn't. The mean PSQI scores among the study participants were 8.91 ± 5.78; the score among those participants with and without headache was 10.57 ± 3.11 and 7.68 ± 2.53, respectively. CONCLUSION: Perceived corona anxiety, poor sleep quality, and corona anxiety are associated with N95-related headaches and SpO2 drop among health professionals who wear N95 masks for at least 4 hours.