N95 Respirators Research Articles

Adverse effects of prolonged use of mask among employees at selected departments in Nedumkandam, Idukki, Kerala

Introduction: “The surgical face mask has become a symbol of our times”. In March 17, 2020 this was headline of an article in the New York Times on the role of face mask during the COVID-19 outbreak. This study was undertaken to assess the effects of prolonged use of mask on physical well-being of employees in selected departments of Nedumkandam, Idukki, Kerala Method: The present study was an explorative study of 110 employees working in different sectors in Nedumkandam. Data were collected by using self-structured questionnaire. . There were total 20 questions related to physical effects of prolonged mask usage.. All participants wore either surgical mask or N95 respirators for a minimum of 6 hours per day. Result: Majority of the participants were male (56.3%) and between the age group of 36-45 years. The result indicated that 80.9% (N=89) were uncomfortable with mask usage. Reported side effects include head ache, breathing difficulty, nasal discomfort, skin related problems, Mask related infection. The majority of the respondents (N=89, 80.9%) report one or more of these adverse effect while 19% (N=21) report none of these side effects. Conclusion: The study was concluded that majority of the employees suffering with various physical discomforts including head ache, nose related problem, breathlessness, skin related problems. Employees who wear masks for extended periods reported increased fatigue and a sense of breathlessness.

Analysis of SARS-CoV-2 transmission in a university classroom based on real human close contact behaviors

Due to high-population density, frequent close contact, possible poor ventilation, university classrooms are vulnerable for transmission of respiratory infectious diseases. Close contact and long-range airborne are possibly main routes for SARS-CoV-2 transmission. In this study, taking a university classroom in Beijing for example, close contact behaviors of students were collected through a depth-detection device, which could detect depth to each pixel of the image, based on semi-supervised learning. Finally, >23 h of video data were obtained. Using Computational Fluid Dynamics, the relationship between viral exposure and close contact behaviors (e.g. interpersonal distance, relative facial orientations, and relative positions) was established. A multi-route transmission model (short-range airborne, mucous deposition, and long-range airborne) of infectious diseases considering real close contact behaviors was developed. In the case of Omicron, the risk of infection in university classrooms and the efficacy of different interventions were assessed based on dose-response model. The average interpersonal distance in university classrooms is 0.9 m (95 % CI, 0.5 m–1.4 m), with the highest proportion of face-to-back contact at 87.0 %. The risk of infection of susceptible students per 45-min lesson was 1 %. The relative contributions of short-range airborne and long-range airborne transmission were 40.5 % and 59.5 %, respectively, and the mucous deposition was basically negligible. When all students are wearing N95 respirators, the infection risk could be reduced by 96 %, the relative contribution of long-range airborne transmission increases to 95.6 %. When the fresh air per capita in the classroom is 24 m3/h/person, the virus exposure could be decreased by 81.1 % compared to the real situation with 1.02 m3/h/person. In a classroom with an occupancy rate of 50 %, after optimized arrangement of student distribution, the infection risk could be decreased by 62 %.

Incidence of Fit Test Failure During N95 Respirator Reuse and Extended Use

The COVID-19 pandemic resulted in a widespread acute shortage of N95 respirators, prompting the Centers for Disease Control and Prevention to develop guidelines for extended use and limited reuse of N95s for health care workers (HCWs). While HCWs followed these guidelines to conserve N95s, evidence from clinical settings regarding the safety of reuse and extended use is limited. To measure the incidence of fit test failure during N95 reuse and compare the incidence between N95 types. This prospective cohort study, conducted from April 2, 2021, to July 15, 2022, at 6 US emergency departments (EDs), included HCWs who practiced N95 reuse for more than half of their clinical shift. Those who were unwilling to wear an N95 for most of their shift, repeatedly failed baseline fit testing, were pregnant, or had facial hair or jewelry that interfered with the N95 face seal were excluded. Wearing the same N95 for more than half of each clinical shift and for up to 5 consecutive shifts. Participants chose an N95 model available at their institution; models were categorized into 3 types: dome (3M 1860R, 1860S, and 8210), trifold (3M 1870+ and 9205+), and duckbill (Halyard 46727, 46767, and 46827). Participants underwent 2 rounds of testing using a different mask of the same type for each round. The primary outcome was Occupational Safety and Health Administration-approved qualitative fit test failure. Trained coordinators conducted fit tests after clinical shifts and recorded pass or fail based on participants tasting a bitter solution. A total of 412 HCWs and 824 N95s were fit tested at baseline; 21 N95s (2.5%) were withdrawn. Participants' median age was 34.5 years (IQR, 29.5-41.8 years); 252 (61.2%) were female, and 205 (49.8%) were physicians. The overall cumulative incidence of fit failure after 1 shift was 38.7% (95% CI, 35.4%-42.1%), which differed by N95 type: dome, 25.8% (95% CI, 21.2%-30.6%); duckbill, 28.3% (95% CI, 22.2%-34.7%); and trifold, 61.3% (95% CI, 55.3%-67.3%). The risk of fit failure was significantly higher for trifold than dome N95s (adjusted hazard ratio, 1.75; 95% CI, 1.46-2.10). In this cohort study of ED HCWs practicing N95 reuse, fit failure occurred in 38.7% of masks after 1 shift. Trifold N95s had higher incidence of fit failure compared with dome N95s. These results may inform pandemic preparedness, specifically policies related to N95 selection and reuse practices.

A meta-analysis evaluating the effect of N95 respirators in healthcare and non-healthcare providers on laboratory-confirmed respiratory virus infection

A meta-analysis evaluating the effect of N95 respirators in healthcare and non-healthcare providers on laboratory-confirmed respiratory virus infection

Microscopy of Woven and Nonwoven Face Covering Materials: Implications for Particle Filtration.

A suite of natural, synthetic, and mixed synthetic-natural woven fabrics, along with nonwoven filtration layers from a surgical mask and an N95 respirator, was examined using visible light microscopy, scanning electron microscopy, and micro-X-ray computed tomography (µXCT) to determine the fiber diameter distribution, fabric thickness, and the volume of solid space of the fabrics. Nonwoven materials exhibit a positively skewed distribution of fiber diameters with a mean value of ≈3 μm, whereas woven fabrics exhibit a normal distribution of diameters with mean values roughly five times larger (>15 μm). The mean thickness of the N95 filtration material is 1093 μm and is greater than that of the woven fabrics that span from 420 to 650 μm. A new procedure for measuring the thickness of flannel fabrics is proposed that accounts for raised fibers. µXCT allowed for a quantitative nondestructive approach to measure fabric porosity as well as the surface area/volume. Cotton flannel showed the largest mean isotropy of any fabric, though fiber order within the weave is poorly represented in the surface electron images. Surface fabric isotropy and surface area/volume ratios are proposed as useful microstructural quantities to consider for future particle filtration modeling efforts of woven materials.

N95 Respirators for Cardiovascular Protection During Wildfire Smoke Events.

N95 Respirators for Cardiovascular Protection During Wildfire Smoke Events.

Comparative Evaluation of Microorganism Disinfection Methods for N95 Respirators

Background: An excessive demand for N95 respirators occurred during the SARS-CoV-2 pandemic. Therefore, health care workers were obligated to reuse N95 respirators, which were intended to be disposable. Aim: The primary objective of this study was to establish a standard procedure for safe disinfection or sterilization that does not affect the performance of an N95 respirator. Methods: As disinfection or sterilization methods, immersion in 70% ethanol, 0.1% hypochlorous acid, 0.3% peracetic acid, 0.2% alkyldiaminoethylglycine hydrochloride aqueous solution, hypochlorous acid water, or plant mineral-activated water, autoclaving, pasteurization and hydrogen peroxide plasma sterilization were used. After sterilization/disinfection, the filtration capacity of each N95 respirator was examined. Findings: The performance changes in the N95 respirator caused by each sterilization/disinfection method differed for each manufacturer’s product. Seventy percent ethanol, 0.1% sodium hypochlorite aqueous solution, 0.3% peracetic acid aqueous solution, autoclaving, hypochlorous acid water, and plant mineral-activated water significantly deteriorated the performance of N95 respirators. Performance degradation (increased permeability) was observed in 0.2% alkyldiaminoethylglycine hydrochloride aqueous solution and hydrogen peroxide plasma sterilization, and the permeation performance significantly deteriorated by 50–70% in all N95 respirators tested. Only pasteurization resulted in no deterioration in performance, even after five repeated sterilizations. Conclusion: Verification of sterilization/disinfection methods for the reuse of N95 respirators has shown that the currently recommended hydrogen peroxide plasma sterilization is inadequate as it increases permeability by more than 50% with a single treatment. In this study, pasteurization was found to be the optimal sterilization method.

Effect of Combined Oxygen Therapy and Use of a Surgical Mask or N95 Mask on Inspired Oxygen Fraction and Expired Carbon Dioxide Fraction.

Combined use of a surgical mask and oxygen mask might decrease the inspired oxygen concentration and increase the risk of hypercapnia. We investigated the fraction of inspired oxygen (FiO2) and end-tidal carbon dioxide (ETCO2) under different combinations of masks and oxygen flows. Five healthy volunteers were administered oxygen using the following methods: oxygen mask alone (O group), oxygen mask over a surgical mask (S group), and oxygen mask over an N95 mask (N group). FiO2 and ETCO2 were measured at oxygen flow rates of 0, 5, and 8L/min under each mask condition. At oxygen flow rates of 5 and 8L/min, FiO2 was lower in the order of N group (0.32 at 5L/min, 0.36 at 8L/min), S group (0.45 at 5L/min, 0.52 at 8L/min), and O group (0.61 at 5L/min, 0.73 at 8L/min). ETCO2 was higher in the order of N, S, and O groups. In conclusion, wearing the oxygen mask over the surgical mask or N95 mask reduces FiO2 and increases ETCO2 in healthy volunteers. Since patients who have emerged from general anaesthesia are more likely to have worse respiratory conditions, they need close observation to avoid hypoxemia and hypercapnia.

Effect of surgical mask and N95 respirator mask use on cerebrovascular reactivity.

<p>Face masks are crucial parts of personal protective equipment (PPE) to reduce the risk of respiratory infections. The COVID-19 outbreak has increased healthcare workers&rsquo; use of face masks. This study aimed to evaluate changes in cerebrovascular response among healthcare workers using surgical and N95 respirator masks.&nbsp;</p>. <p>90 healthcare workers: 30 wearing surgical masks, 30 wearing N95 respirators, and 30 without masks were included. After two-hour of face mask use, the baseline mean flow velocity (MFV) and the mean breath-holding index (BHI) of the bilateral middle cerebral arteries (MCAs) were evaluated with transcranial Doppler ultrasound. The presence of de-novo headache was recorded. BHI values ​​below 0.69 were evaluated as a sign of impaired cerebrovascular reactivity (CVR).&nbsp;</p>. <p>The rate of de-novo headache was significantly higher in the N95 respirator mask group (p = 0.004). Compared to the control and surgical mask groups, the N95 respirator mask group had significantly lower values of the baseline MFV of the right MCA (p = 0.003 and p = 0.021, respectively) and mean BHI (p = 0.003 and p = 0.012, respectively). Still, only one N95 respirator mask user had a mean BHI value below 0.69.</p>. <p>Surgical masks did not signi&shy;fi&shy;cantly affect cerebral hemodynamics. Although N95 respirator mask use significantly decreased BHI values, the CVR is still within normal limits, and the development of de-novo headache is not directly associated with low CVR.&nbsp;</p>.

Comparison of Face Masks by Arduino Sensors

&#x0D; &#x0D; &#x0D; The COVID-19 pandemic in early 2020 has created a health crisis around the world. There have been many precautions taken against the virus, such as social distancing and the use of personal protective equipment. Face masks are an essential part of personal protective equipment, especially for essential workers. Although the pandemic has caused a high demand for facemasks, there is limited scientific knowledge available on the various types of masks. Knowledge about the air quality inside the different facemasks could be beneficial for both the COVID-19 pandemic and future disease outbreaks, which will seemingly increase in the future. There are different types of masks, ranging from tight-fitting N95 respirator masks to looser surgical masks to homemade cloth masks. Herein, N95 respirator masks, surgical masks, cloth face masks, and surgical masks on top of N95 respirator masks were compared in terms of CO2 levels, Volatile Organic Compound levels (VOCs), temperature, humidity, and O2 concentrations. To record these measurements, Arduino-based sensors were constructed and utilized for the measurements. It was found that the N95 mask and the surgical mask on top of the N95 mask trapped the highest concentration of carbon dioxide, VOCs, temperature, humidity, and the lowest oxygen levels compared to the surgical mask and cloth mask.&#x0D; &#x0D; &#x0D;

Why Face Masks Should not be Imposed on the Public Again: A Review Article

Viral epidemics of acute respiratory infections pose a global threat. Influenza outbreaks occur almost every year. Specifically, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19), emerged in late 2019. This unprecedented event resulted in many countries requiring masks in public spaces to contain the spread of SARS-CoV-2. However, the early and previous systematic reviews of randomized controlled trials (RCTs) found that medical/surgical masks did not appear to reduce respiratory viral infections. Also, N95 respirators did not provide superior protection over surgical masks against viral infections or influenza-like infections among healthcare workers (HCWs), although N95 respirators theoretically provide better protection. This led to the recommendation not to wear facemasks as potential benefits are limited, and there is a risk of self-contamination if misused. However, with the ongoing spread of SARS-CoV-2, several health authorities suddenly shifted their recommendations and advised the general public to wear masks, with some governments even mandating it. By July 2023, the health-protective benefits of wearing facemasks are still conflicting, and debate over the idea of a mask mandate is ongoing. Therefore, this review aims to discuss ten reasons why face masks should not be imposed on the public again, which include the functional weaknesses of facemasks, lack of justification for the sudden change in the recommendations during the COVID-19 pandemic, the effectiveness of facemasks in the community and among HCWs based on the systematic reviews of the RCTs, their effectiveness based on the RCTs, the effectiveness of N95 respirators versus surgical masks in protecting from acute respiratory infection based on the systematic reviews, their potential harms, the poor quality of most masks used by the public, their misuse, the trajectory of the COVID-19 pandemic despite masking, and the importance of acknowledgment of the rights of people in wearing masks or not.

Strategies to maintain an N95 respirator supply during a pandemic supply-chain shortage.

Strategies to maintain an N95 respirator supply during a pandemic supply-chain shortage.

Lesões de pele associadas ao uso de respiradores N95 entre profissionais de saúde no Brasil em 2020

Objective: to investigate the prevalence of skin lesions and factors associated with the use of N95 respirators among health professionals in Brazil. Method: cross-sectional study conducted with 11,368 health professionals using a respondent-driven sampling method adapted for online environments. Univariate and multivariate analyses were performed to investigate the association between the “skin lesions with the use of N95 respirators” variable and gender, professional category, workplace, training, COVID-19 diagnosis, and availability of sufficient and high-quality Personal Protective Equipment. Results: the prevalence of skin lesions was 61.8%. Women were 1.203 times (95% CI: 1.154-1.255) more likely to develop a lesion than men. The chances of skin lesions in psychologists (PR=0.805; 95% CI: 0.678-0.956) and dentists (PR=0.884; 95% CI: 0.788-0.992), were lower when compared to Nursing professionals. Professionals with a positive COVID-19 diagnosis and working in the Intensive Care Unit have an increased chance of presenting skin lesions (PR=1.074; 95% CI: 1.042-1.107); (PR=1.203; 95% CI: 1.168-1.241), respectively. Conclusion: the prevalence of skin lesions caused by the use of N95 respirators was 61.8% and was associated with female gender, professional category, workplace, training, COVID-19 diagnosis, and availability of sufficient and highquality Personal Protective Equipment.

A re-usable, locally manufactured, half-face respirator provides better protection than fitted disposable N95 masks

BACKGROUND The coronavirus disease 2019 pandemic has led to persistent shortages of respiratory protective equipment in many jurisdictions. Re-usable industrial respirators have been proposed and deployed as an alternative, but also face severe supply limitations. Numerous respirator designs have been proposed since the start of the current pandemic, but few have been systematically tested on healthcare workers (HCWs). OBJECTIVE In this paper, we describe a locally manufactured respirator named ‘Duo’ that includes separate, valved, inspiratory and expiratory pathways and accommodates up to two filters. Duo was compared with the disposable commercial N95 in a cohort of 41 HCWs using standardised quantitative fit-testing. DESIGN A prospective observational cross-sectional study. SETTING Conducted between May and June 2020 among HCWs at Toronto General Hospital. PARTICIPANTS Forty-one HCWs of both sexes working at Toronto General Hospital. MAIN OUTCOME MEASURES Quantitative fit-testing involving seven tests as prescribed by Canadian standard CSA Z94.4-18. We measured the median overall fit-factors; the individual manoeuvre fit-factors and pass rate. RESULTS The median [IQR] overall fit-factors were 2947 [2228 to 4405] and 77.2 [51.9 to 152.1] for the Duo and disposable N95 respirators respectively (P &lt; 0.0001). The overall pass rate of quantitative fit-testing fitted disposable N95 was 58.5% (24/41), and 100% for the Duo. CONCLUSIONS A re-usable, locally manufactured, half-face respirator performs better than fitted disposable N95 masks as assessed by quantitative fit-testing. This can help address the global supply disruption for a better response to future pandemics. The device requires further modification and testing to optimise exhalation flow resistance, and full conformance with technical standards is required for regulatory approval.

Skin lesions associated with the use of N95 respirators among health professionals in Brazil in 2020.

to investigate the prevalence of skin lesions and factors associated with the use of N95 respirators among health professionals in Brazil. cross-sectional study conducted with 11,368 health professionals using a respondent-driven sampling method adapted for online environments. Univariate and multivariate analyses were performed to investigate the association between the "skin lesions with the use of N95 respirators" variable and gender, professional category, workplace, training, COVID-19 diagnosis, and availability of sufficient and high-quality Personal Protective Equipment. the prevalence of skin lesions was 61.8%. Women were 1.203 times (95% CI: 1.154-1.255) more likely to develop a lesion than men. The chances of skin lesions in psychologists (PR=0.805; 95% CI: 0.678-0.956) and dentists (PR=0.884; 95% CI: 0.788-0.992), were lower when compared to Nursing professionals. Professionals with a positive COVID-19 diagnosis and working in the Intensive Care Unit have an increased chance of presenting skin lesions (PR=1.074; 95% CI: 1.042-1.107); (PR=1.203; 95% CI: 1.168-1.241), respectively. the prevalence of skin lesions caused by the use of N95 respirators was 61.8% and was associated with female gender, professional category, workplace, training, COVID-19 diagnosis, and availability of sufficient and highquality Personal Protective Equipment. (1) The overall prevalence of skin lesions was 61.8%. (2) The most affected professional category was Nursing. (3) Women were more likely to develop skin lesions than men.

Skin lesions associated with the use of N95 respirators among health professionals in Brazil in 2020

Objetivo: investigar a prevalência de lesões de pele e fatores associados ao uso de respiradores N95 entre profissionais de saúde no Brasil. Método: estudo transversal realizado com 11.368 profissionais de saúde por meio de um método de amostragem dirigido por respondentes adaptado para ambientes online. Análises univariadas e multivariadas foram realizadas para investigar a associação entre a variável “lesão de pele com uso de respirador N95” e sexo, categoria profissional, local de trabalho, treinamento, diagnóstico de COVID-19 e disponibilidade suficiente de equipamentos de proteção individual de qualidade. Resultados: a prevalência de lesões cutâneas foi de 61,8%. As mulheres foram 1,203 vezes (IC 95%: 1.154-1.255) mais propensas a desenvolver uma lesão do que os homens. As chances de lesão de pele em psicólogos (RP=0,805; IC 95%: 0,678-0,956) e dentistas (RP=0,884; IC 95%: 0,788-0,992) foram menores quando comparados aos profissionais de Enfermagem. Profissionais com diagnóstico positivo para COVID-19 e que trabalham em Unidade de Cuidados Intensivos têm maior chance de apresentar lesões de pele (RP=1,074; IC 95%: 1,042-1,107); (RP=1,203; IC 95%: 1,168- 1,241), respectivamente. Conclusão: a prevalência de lesões de pele causadas pelo uso do respirador N95 foi de 61,8% e esteve associada ao sexo feminino, categoria profissional, local de trabalho, treinamento, diagnóstico de COVID-19 e disponibilidade suficiente de equipamentos de proteção individual de qualidade.

Importance of Dipole Orientation in Electrostatic Aerosol Filtration.

Electrostatic charge is a major part of modern-day aerosol filtration media (e.g., N95 respirators and surgical facemasks) that has remained poorly understood due to its complicated physics. As such, charging a fibrous material has relied on empiricism in dire need of a mathematical foundation to further advance product design and optimization. In this concern, we have conducted a series of numerical simulations to improve our understanding of how an electrostatically charged fiber captures airborne particles and to quantify how the fiber's dipole orientation impacts its capture efficiency. Special attention was paid to the role of Coulomb and dielectrophoretic forces in the capture of particles of different charge polarities (e.g., particles having a Boltzmann charge distribution). Simulation results were compared with the predictions of the popular empirical correlations from the literature and discussed in detail. Predictions of the empirical correlations better agreed with the simulation results obtained for fibers with a dipole perpendicular to the flow direction rather than for fibers with a dipole parallel to the flow. This indicates that such empirical correlations are more suitable for filters charged via contact electrification (friction charging), where the dipoles are mostly perpendicular to the flow direction, and less suitable for corona-charged media, where the fiber dipoles are generally parallel to the flow direction.

Spreading a Durable Protective Layer of Quaternary Ammonium Agents on an N95 Respirator for Predecontamination of Airborne Mycobacterium tuberculosis and Viruses Using Mycobacterium smegmatis and Bacteriophage MS2 as Models

Tuberculosis (TB) and coronavirus disease 2019 (COVID-19), caused by Mycobacterium tuberculosis (MTB) and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), respectively, are serious public health issues. N95 respirators are commonly used to protect people from infections in high-risk environments. Consequently, we used Mycobacterium smegmatis and bacteriophage MS2 as MTB and SARS-CoV-2 surrogates to evaluate the ability of a quaternary ammonium agent (QAA) coating on the surface of new N95 respirators to reduce the microbial burden upon aerosol exposure. Regarding the burden (105 CFU (or PFU)/m3) of M. smegmatis and MS2 phage that settled onto the respirator surface, the QAA yielded average reduction efficiencies ( R % ) of 92.4% and 99.8%, respectively. In addition, the antimicrobial activity of the coated respirator was maintained for one week. For bioaerosols that contacted the respirator (105 CFU (or PFU)/m3), the R % of the QAA was 90.7% for M. smegmatis and 94.4% for MS2 phage on the outermost layer of the respirator. Moreover, filtration efficiencies between a QAA-coated respirator and an untreated respirator were not significantly altered ( p = 0.332 ). These results demonstrate that this QAA product has a durable antimicrobial activity and could reduce the MTB and SARS-CoV-2 concentrations on the N95 respirator surface. However, it is recommended that such a coating respirator not be worn for more than 4 hours based on hemolysis assay results.

Effectiveness of wearing masks during the COVID-19 outbreak in cohort and case-control studies: a systematic review and meta-analysis.

To evaluate the efficacy of wearing a mask to prevent COVID-19 infection. This was a systematic review and meta-analysis of cohort and case-control studies, considering the best level of evidence available. Electronic databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Clinical Trials.gov) were searched to identify studies that evaluated the effectiveness of wearing masks compared with that of not wearing them during the COVID-19 pandemic. Risk of bias and quality of evidence were assessed using the Cochrane risk of bias tool and the Grading of Recommendations Assessment, Development, and Evaluation. Of the 1,028 studies identified, 9 met the inclusion criteria (2 cohort studies and 7 case-control studies) and were included in the analysis. The meta-analysis using cohort studies alone showed statistically significant differences, wearing a cloth mask decreased by 21% [RD = -0.21 (95% CI, -0.34 to -0.07); I2 = 0%; p = 0,002] the risk of COVID-19 infection, but the quality of evidence was low. Regarding case-control studies, wearing a surgical mask reduced the chance of COVID-19 infection [OR = 0.51 (95% CI, 0.37-0.70); I2 = 47%; p = 0.0001], as did wearing an N95 respirator mask [OR = 0.31 (95% CI, 0.20-0.49); I2 = 0%; p = 0.00001], both with low quality of evidence. In this systematic review with meta-analysis, we showed the effectiveness of wearing masks in the prevention of SARS-CoV-2 infection regardless of the type of mask (disposable surgical mask, common masks, including cloth masks, or N95 respirators), although the studies evaluated presented with low quality of evidence and important biases.

Effects of N95 Masks on Cerebral Oxygen Saturation and End-Tidal Carbon Dioxide Partial Pressure in Healthcare Workers

Background: Healthcare workers must wear masks throughout their shifts, especially those in operating rooms for long periods. Objectives: This study evaluated the effects of wearing N95 masks on blood and cerebral oxygen saturation levels for three hours. Methods: The present case-control study enrolled 20 operating room workers wearing N95 masks. Their blood oxygen saturation (SaO2), end-tidal carbon dioxide partial pressure (PETCO2), and right- and left-sided cerebral regional oxygen saturation (rSO2) were measured in the beginning (0 h) and after wearing N95 masks for one and three hours. Results: Wearing a mask affected PETCO2, rSO2, and pulse rate and caused fatigue and lightheadedness in some cases. The participants' mean PETCO2 increased significantly, from 32 mmHg before putting on a mask to 38 mmHg after wearing it for three hours (P &lt; 0.05). No significant change was observed in the participants' mean rSO2, though changes in their rSO2 levels were recorded (P &gt; 0.05). Conclusions: We showed evidence of changes in different physiology parameters due to using masks for 1 to 3 h. Notably, wearing an N95 mask increased end-tidal carbon dioxide partial pressure and decreased cerebral oxygen saturation in individual cases, not all cases.