BACKGROUND: The protective effectiveness of an N95 respirator depends on the filtration efficiency of the material from which the N95 respirator is made of, as well as the wearers' facial fit. The facial fit of an N95 respirator mainly depends on the degree of matching between the wearers' facial dimension characteristics and the N95 respirator. Quantitative fit testing objectively evaluates the fit of N95 respirators; however, it is not easy to promote because of the limitations of testing conditions. The aim of this study is to establish a fit prediction model of N95 respirator based on facial images. METHODS: Facial images and fit factor (FF) value of 5 N95 respirators were gathered from 299 medical staffs in 10 hospitals in Beijing. Face geometry measurement was based on 3D face modelling, and the American TSI-8038 Porta Count Pro+ was used to conduct quantitative fit test. Multiple linear regression analysis was employed to identify facial dimensional features that significantly influenced the fit of N95 respirators. Through matching training of facial image and FF values, a fit prediction model has been established, enabling rapid recommendation of N95 respirators meeting the fit standard via facial image recognition. RESULTS: A fit prediction model for N95 respirators based on facial images has been developed, which enables the rapid recommendation of N95 respirators with acceptable FF value for healthcare personnel. The model demonstrated an accuracy of 55.93%, a precision of 98.43%, a recall of 51.65%, and an F1 score of 0.68. CONCLUSIONS It is feasible to utilize computer-based facial recognition technology to rapidly recommend N95 respirators for medical personnel. Given the high level of accuracy achieved, the model demonstrates significant potential for practical application.
Humans ; Face/anatomy & histology* ; N95 Respirators/standards* ; Male ; Adult ; Female ; Middle Aged ; Beijing

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.
Male ; Humans ; Female ; N95 Respirators ; COVID-19/epidemiology* ; Masks ; Pandemics/prevention & control* ; Respiratory Protective Devices ; Materials Testing ; Equipment Design ; Occupational Exposure/prevention & control*

Objectives: To develop our own qualitative fit test kit and protocol for respirators and validate this against the manufacturer-issued kit. Methods: This is a crossover study of 50 healthcare workers in a tertiary government hospital. Some healthcare workers were tested multiple times according to the number of respirators they want tested. Qualitative fit testing was done according to manufacturer protocol for the commercial kits or according to our own protocol for the novel kits. Results: A total of 63 fit tests were analyzed. This novel kit was determined to be noninferior to manufacturer-issued kits in detecting leaks among worn respirators (p=0.005). Conclusion A fit test kit can be successfully created from readily available household and hospital materials. Fit tests with these novel kits using our validated protocol are shown to be noninferior to commercial test kits. This can greatly aid in qualitative fit testing of respirators in a logistically constrained pandemic setting.
healthcare workers ; respirators ; SARS-CoV-2

COVID-19 ; Health Personnel ; Humans ; Masks ; N95 Respirators ; Pandemics ; SARS-CoV-2

Objective: We determined if there was a significant change in the intraocular pressure (IOP) of healthcare workers with extended use of N95 masks. Methods: This was a prospective time-series study involving 58 eyes of 29 healthcare workers who were assigned to 3 groups: surgical mask (control) and 2 intervention arms consisting of valved N95 (8511, 3M, USA) and non-valved N95 (8210, 3M, USA) masks. Each participant underwent IOP measurements of both eyes by Goldmann applanation tonometry at baseline, 5 minutes, 1 and 4 hours of mask use on three separate days. The primary outcome was the difference in IOP between the N95 and surgical mask groups. Results: Mean baseline IOP of the cohort was 13.85 ± 1.11 mmHg with no significant difference among the groups. Compared to surgical mask use, mean IOP was increased at the 1 hour and 4 hour time points with valved N95 use (+0.88, p<0.001; +1.48, p<0.001 respectively) and increased at the 5 minute, 1 hour and 4 hour time points with nonvalved N95 use (+0.52, p=0.01; +1.07 p<0.001; +1.62, p<0.001, respectively). Conclusion There was a statistically significant increase in IOPs with prolonged N95 mask use. However, the levels of IOP increase were less than 2 mmHg and may be not clinically significant.
Intraocular Pressure ; N95 Respirators ; Glaucoma

Background: In the time of the COVID-19 pandemic, the use of personal protective equipment (PPE) as an infection control measure is recommended for healthcare settings to prevent the spread of the virus. However, given the increased demand for PPEs worldwide and the limited resources available in the country, supply shortages are experienced by many healthcare facilities and workers. Furthermore, most PPEs should be discarded after use and may only be reused under emergency situations. Thus, the study sought to determine how to maximize PPE usage. Objective: The study aimed to compare the effect of Ultraviolet Germicidal Irradiation (UVGI) against Bacillus subtilis between 30 and 40-minute periods. Specifically, the study targetted to establish if there is a difference in the mean percent reduction in CFUs of B. subtilis between that of the 40-minute and 30-minute treatment group of N95 FFRs and coverall suits. Methodology: The study is a secondary research which builds upon the experimental results of the commissioned study conducted by the Department of Medical Microbiology (DMM), College of Public Health, University of the Philippines Manila researchers to conduct data analysis. Furthermore, the PPE evaluated were coverall suits and N95 filtering facepiece respirators. They inoculated a total of 30 samples with B. subtilis for each type of PPE and subjected them to UVGI treatment in 30 and 40-minute periods. This study then employed inferential statistics, particularly a two-sample independent t-test, to further analyze the data from DMM and assess the difference between the two UVGI exposure durations on PPE decontamination. Results: After calculating and analyzing the data using OpenEpi, the mean percent reduction was statistically greater (p-value = <0.0000001, α = 0.05) in the 40-minute exposure than the 30-minute exposure. The mean percent reductions of the N95 respirators were 98.68% and 99.41% for the 30 and 40-minute exposures, respectively. On the other hand, the mean percent reductions of the coverall suits were 80.40% and 99.71% for the 30 and 40-minute exposures. Conclusion Based on the significant difference in bacterial reduction between the two time exposures, the longer UVGI time exposure was more effective as a disinfectant. The results of the study contributed to knowledge on infection control using UVGI and its possibility as a method of decontaminating PPEs.
N95 Respirators

COVID-19/therapy* ; Equipment and Supplies ; Female ; Humans ; Infant, Newborn ; N95 Respirators ; Patient Isolators ; Personal Protective Equipment ; Practice Guidelines as Topic ; Pregnancy ; Pregnancy Complications, Infectious ; Respiratory Protective Devices ; Resuscitation/methods* ; SARS-CoV-2 ; Singapore