N95 respirator use during advanced pregnancy

The influence of N95 and surgical masks on carbon dioxide levels: A comprehensive systematic review and meta-analysis

Objectives

This study aimed to assess the impact of wearing N95 and surgical masks on carbon dioxide (CO2) concentrations during various activity levels, to understand the implications for mask use in different settings, especially in light of the COVID-19 pandemic.

Study design

Systematic Review and Meta-Analysis.

Methods

A systematic review was conducted, retrieving 6798 articles from PubMed, Web of Science, and Scopus databases. Twenty-nine articles met the inclusion criteria. Mask types were categorized into N95 and surgical masks, while activities were classified as low, medium, and high.

Results

The meta-analysis revealed CO2 concentrations (mmHg) for different scenarios: No mask (37.91, 95 % CI: 36.46, 39.35), N95-low (36.83, 95 % CI: 33.57, 40.10), N95-moderate (37.85, 95 % CI: 36.51, 39.20), N95-high (39.51, 95 % CI: 38.00, 41.02), N95 with exhalation valve (35.82, 95 % CI: 32.89, 38.75), N95 without exhalation valve (38.45, 95 % CI: 37.10, 39.81), surgical mask-low (38.31, 95 % CI: 34.48, 42.14), surgical mask-moderate (35.05, 95 % CI: 31.12, 38.97), surgical mask-high (36.07, 95 % CI: 34.18, 37.96).

Conclusions

Our findings indicate that N95 masks lead to higher CO2 accumulation during various activities compared to surgical masks. Moreover, surgical masks exhibit higher CO2 concentrations during low activity compared to moderate and high activities. Notably, CO2 concentrations are higher in N95 masks without an exhalation valve compared to those with a valve. No significant difference was observed between not wearing a mask and wearing either N95 or surgical masks in terms of CO2 accumulation. These results provide important insights for mask selection and usage recommendations in different scenarios.

Which Mask, N95 or Surgical Mask, Causes Hoarseness in Healthcare Workers?

OBJECTIVES

This study aimed to determine the impact of different types of masks on the voices of healthcare professionals who had to wear masks for an extended amount of time during the pandemic period and had a healthy voice.

METHODS

Our research included 41 healthcare workers. The participants were separated into two groups: surgical (n = 21) and N95 mask users (n = 20). Healthcare workers evaluated masks before and after wearing them for at least 8 hours throughout the workday. All subjects had a videolaryngoscopic examination; the Voice Handicap Index-10 (VHI-10), GRBAS, acoustic voice analysis (F0, jitter%, shimmer%, noise/harmonic ratio, relative average perturbation [RAP]), aerodynamic measures (maximum phonation time, MPT), and blood oxygen saturation were evaluated.

RESULTS

Although both groups' VHI-10 scores increased after using the mask, this rise was not statistically significant in our research. According to the GRBAS classification, voice quality deterioration was identified in 9.6% (mild-moderate) of the group using surgical masks and 15% (mild) of the group wearing N95. Only the jitter and RAP values of individuals wearing both surgical and N95 masks were determined to be statistically significant. There was no significant change in MPT following mask wear in either group. Both the surgical and N95 mask-using groups showed a substantial drop in blood oxygen saturation before and after mask usage.

CONCLUSION

There was no change in voice quality between healthcare workers wearing surgical and N95 masks. It has been noticed that voice perception and quality are affected by the mask's barrier effect rather than the kind of mask.

Health effects of filtering facepiece respirators: Research and clinical implications of comfort, thermal, skin, psychologic, and workplace effects

Filtering facepiece respirators (FFR's) such as N95s have become widely used in appropriate settings for personal respiratory protection and are increasingly used beyond workplace settings. Concerns about possible adverse effects have appeared in many publications, particularly since the COVID-19 pandemic led to much more widespread use. This paper synthesizes known effects based upon review of publications in PubMed since 1995, addressing effects other than pulmonary and cardiovascular (reviewed elsewhere). Findings: (1) Subjective discomfort is very frequently reported; this includes general discomfort or organ-system-specific complaints such as respiratory, headache, dermatologic, and heat. Research methods are widely divergent, and we propose a taxonomy to classify such studies by methodology, study population (subjects, experimental vs. observational methodology, comparator, specificity, and timeframe) to facilitate synthesis. (2) Objective measures of increased heat and humidity within the mask are well documented. (3) Frequency and characteristics of dermatologic effects have been insufficiently evaluated. (4) Physical mask designs are varied, making generalizations challenging. (5) More studies of impact on work performance and communication are needed. (6) Studies of effect of FFR design and accompanying training materials on ease and consistency of use are needed.

A Comparative Evaluation of the Effects of N95 and Surgical Facemasks on Pregnant Women Performing Moderate-Intensity Exercise: A Prospective Randomized Study

Background and objective A facemask is often indicated for the control of the spread of airborne pathogens. At the peak of the COVID-19 pandemic, there was mass enforcement of mask use across the globe. Pregnant women were not excluded. While several studies have been conducted to evaluate and compare the efficacy of various mask types, data on their effects on pregnant women during exercise are scarce. The objective of this study was to evaluate and compare the effects of N95 and surgical facemasks on the cardiopulmonary functions of pregnant women during moderate-intensity exercise. Methods A prospective randomized study was conducted among 104 healthy women with advanced singleton pregnancies performing moderate-intensity exercise wearing either surgical or N95 masks during routine antenatal care. Their respiratory rates were counted, and arterial oxygen saturation (SPO2) and radial pulses (heart rates) were recorded with a mobile digital pulse oximeter at baseline and after 30 minutes of exercise. The mean values were calculated. Data analysis was done using Statistical Product and Service Solutions (SPSS, version 25; IBM SPSS Statistics for Windows, Armonk, NY). An independent t-test was used to compare the mean SPO2 and radial pulse between the two groups. Chi-square was used to examine differences in categorical variables. The level of significance was set at 0.05. Results Their demographic profiles and measured baseline parameters were comparable. Following a 30-minute exercise, the N95 mask group had lower mean SPO2 compared to the surgical mask group (95.5% versus 97.0%; P=0.028, 95%CI; -2.607 to 0.15). Further, the N95 group recorded a higher mean heart rate than the surgical mask group ((97.23 b/m versus 95.02b/m, respectively, mean difference (MD)=2.212, P=0.021, 95%Cl: 1.249-3.672). The mean respiratory rates were also higher among women in the N95 mask group (32.1 c/m versus 29.08 c/m, MD=3.018, 95%CI: 1.392-4.662, P=0.001). Conclusion The study, comparing the relative effects of the surgical and N95 facemask on the cardiorespiratory functions of exercising pregnant women, findings suggest that surgical facemasks may be better tolerated in advanced pregnancy when performing routine antenatal aerobic exercise in comparison with N95 masks.

Physiologic effects of surgical masking in children versus adults

Background

Surgical masks remain a focal part of the CDC guidelines to decrease COVID-19 transmission. Evidence refuting significant effects of masking on ventilation is mostly limited to small studies, with a paucity of studies on children, and none comparing children to adults.

Methods

A total of 119 subjects were enrolled (71 adults, 49 children) in a prospective interventional study with each subject serving as their own mask-free control. End tidal CO2 (ETCO2), inspired CO2 (ICO2), and respiratory rate were measured by nasal cannula attached to an anesthesia machine D-fend module. Pulse oximetry and heart rate were also followed. After the mask-free period, an ASTM Level 3 disposable surgical mask was donned and 15 min of mask-worn data were collected.

Results

A steady state was confirmed for ETCO2 and ICO2 over the masked period, and mean ICO2 levels rose significantly (p < 0.001) after masking in all age groups. The increase in ICO2 for the 2- to 7-year-old group of 4.11 mmHg (3.23-4.99), was significantly higher (p < 0.001) than the final ΔICO2 levels for both the 7- to 14-year-old group, 2.45 mmHg (1.79-3.12), and adults, 1.47 mmHg (1.18-1.76). For the pediatric group there was a negative, significant correlation between age and ΔICO2, r = -0.49, p < 0.001. Masking resulted in a statistically significant (p < 0.01) rise in ETCO2 levels of 1.30 mmHg in adults and 1.36 mmHg in children. The final respective ETCO2 levels, 34.35 (33.55-35.15) and 35.07 (34.13-36.01), remained within normal limits. Pulse oximetry, heart rate, and respiratory rate were not significantly affected.

Discussion

The physiology of mechanical dead space is discussed, including the inverse relationship of subject age vs ICO2. The methodology and results are compared to previously published studies which detracted from the physiologic safety of surgical masking.

Conclusions

The wearing of a surgical mask results in a statistically significant rise in ICO2 and a smaller rise in ETCO2. Because ETCO2 and other variables remain well within normal limits, these changes are clinically insignificant.

Physio-metabolic and clinical consequences of wearing face masks-Systematic review with meta-analysis and comprehensive evaluation

Background

As face masks became mandatory in most countries during the COVID-19 pandemic, adverse effects require substantiated investigation.

Methods

A systematic review of 2,168 studies on adverse medical mask effects yielded 54 publications for synthesis and 37 studies for meta-analysis (on n = 8,641, m = 2,482, f = 6,159, age = 34.8 ± 12.5). The median trial duration was only 18 min (IQR = 50) for our comprehensive evaluation of mask induced physio-metabolic and clinical outcomes.

Results

We found significant effects in both medical surgical and N95 masks, with a greater impact of the second. These effects included decreased SpO2 (overall Standard Mean Difference, SMD = -0.24, 95% CI = -0.38 to -0.11, p < 0.001) and minute ventilation (SMD = -0.72, 95% CI = -0.99 to -0.46, p < 0.001), simultaneous increased in blood-CO2 (SMD = +0.64, 95% CI = 0.31-0.96, p < 0.001), heart rate (N95: SMD = +0.22, 95% CI = 0.03-0.41, p = 0.02), systolic blood pressure (surgical: SMD = +0.21, 95% CI = 0.03-0.39, p = 0.02), skin temperature (overall SMD = +0.80 95% CI = 0.23-1.38, p = 0.006) and humidity (SMD +2.24, 95% CI = 1.32-3.17, p < 0.001). Effects on exertion (overall SMD = +0.9, surgical = +0.63, N95 = +1.19), discomfort (SMD = +1.16), dyspnoea (SMD = +1.46), heat (SMD = +0.70), and humidity (SMD = +0.9) were significant in n = 373 with a robust relationship to mask wearing (p < 0.006 to p < 0.001). Pooled symptom prevalence (n = 8,128) was significant for: headache (62%, p < 0.001), acne (38%, p < 0.001), skin irritation (36%, p < 0.001), dyspnoea (33%, p < 0.001), heat (26%, p < 0.001), itching (26%, p < 0.001), voice disorder (23%, p < 0.03), and dizziness (5%, p = 0.01).

Discussion

Masks interfered with O2-uptake and CO2-release and compromised respiratory compensation. Though evaluated wearing durations are shorter than daily/prolonged use, outcomes independently validate mask-induced exhaustion-syndrome (MIES) and down-stream physio-metabolic disfunctions. MIES can have long-term clinical consequences, especially for vulnerable groups. So far, several mask related symptoms may have been misinterpreted as long COVID-19 symptoms. In any case, the possible MIES contrasts with the WHO definition of health.

Conclusion

Face mask side-effects must be assessed (risk-benefit) against the available evidence of their effectiveness against viral transmissions. In the absence of strong empirical evidence of effectiveness, mask wearing should not be mandated let alone enforced by law.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021256694, identifier: PROSPERO 2021 CRD42021256694.

Possible toxicity of chronic carbon dioxide exposure associated with face mask use, particularly in pregnant women, children and adolescents - A scoping review

Introduction

During the SARS-CoV-2-pandemic, face masks have become one of the most important ubiquitous factors affecting human breathing. It increases the resistance and dead space volume leading to a re-breathing of CO2. So far, this phenomenon and possible implications on early life has not been evaluated in depth.

Method

As part of a scoping review, literature was systematically reviewed regarding CO2 exposure and facemask use.

Results

Fresh air has around 0.04% CO2, while wearing masks more than 5 min bears a possible chronic exposure to carbon dioxide of 1.41% to 3.2% of the inhaled air. Although the buildup is usually within the short-term exposure limits, long-term exceedances and consequences must be considered due to experimental data. US Navy toxicity experts set the exposure limits for submarines carrying a female crew to 0.8% CO2 based on animal studies which indicated an increased risk for stillbirths. Additionally, mammals who were chronically exposed to 0.3% CO2 the experimental data demonstrate a teratogenicity with irreversible neuron damage in the offspring, reduced spatial learning caused by brainstem neuron apoptosis and reduced circulating levels of the insulin-like growth factor-1. With significant impact on three readout parameters (morphological, functional, marker) this chronic 0.3% CO2 exposure has to be defined as being toxic. Additional data exists on the exposure of chronic 0.3% CO2 in adolescent mammals causing neuron destruction, which includes less activity, increased anxiety and impaired learning and memory. There is also data indicating testicular toxicity in adolescents at CO2 inhalation concentrations above 0.5%.

Discussion

There is a possible negative impact risk by imposing extended mask mandates especially for vulnerable subgroups. Circumstantial evidence exists that extended mask use may be related to current observations of stillbirths and to reduced verbal motor and overall cognitive performance in children born during the pandemic. A need exists to reconsider mask mandates.

Health effects of filtering facepiece respirators: Systematic review of pulmonary and cardiovascular effects

Filtering facepiece respirators (FFRs) were introduced to protect the wearer by removing small particles from inspired air. FFRs are now also used to reduce the spread of transmissible agents from the wearer and are worn outside traditional healthcare and other workplaces. The COVID-19 pandemic increased concerns about potential adverse effects on wearers. A PUBMED query retrieved articles through June 2022. Abstracts and selected full-text articles were systematically reviewed by the authors. This article focuses upon cardiopulmonary physiologic effects (e.g., ventilation, CO₂ elimination, oxygen uptake, and respiratory control) with emphasis upon current and potential research methods as well as summarizing results. 1985 records were identified, of which only 26% were published before 2020. FFR effects on CO₂ elimination appear more likely to be significant than effects on oxygenation or cardiovascular function. While FFRs appear well tolerated by healthy persons, more research is needed for those with pulmonary or cardiac disorders, and for children. Many traditional pulmonary exercise study methods require special care when applied to filtering facepiece respirators. Studying additional parameters may explain the paradox of many subjective discomfort reports despite very limited physiologic effects.

Wildfire Smoke Exposure during Pregnancy: A Review of Potential Mechanisms of Placental Toxicity, Impact on Obstetric Outcomes, and Strategies to Reduce Exposure

Climate change is accelerating the intensity and frequency of wildfires globally. Understanding how wildfire smoke (WS) may lead to adverse pregnancy outcomes and alterations in placental function via biological mechanisms is critical to mitigate the harms of exposure. We aim to review the literature surrounding WS, placental biology, biological mechanisms underlying adverse pregnancy outcomes as well as interventions and strategies to avoid WS exposure in pregnancy. This review includes epidemiologic and experimental laboratory-based studies of WS, air pollution, particulate matter (PM), and other chemicals related to combustion in relation to obstetric outcomes and placental biology. We summarized the available clinical, animal, and placental studies with WS and other combustion products such as tobacco, diesel, and wood smoke. Additionally, we reviewed current recommendations for prevention of WS exposure. We found that there is limited data specific to WS; however, studies on air pollution and other combustion sources suggest a link to inflammation, oxidative stress, endocrine disruption, DNA damage, telomere shortening, epigenetic changes, as well as metabolic, vascular, and endothelial dysregulation in the maternal-fetal unit. These alterations in placental biology contribute to adverse obstetric outcomes that disproportionally affect the most vulnerable. Limiting time outdoors, wearing N95 respirator face masks and using high quality indoor air filters during wildfire events reduces exposure to related environmental exposures and may mitigate morbidities attributable to WS.

A Systematic Review of Whether the Use of N95 Respirator Masks Decreases the Incidence of Cardiovascular Disease in the General Population

The usage of masks such as the N95 has increased exponentially worldwide. With the ever-increasing global rates of cardiovascular disease, it is vital that preventative measures are adopted to help tackle this crisis. N95 masks have been promoted as health prevention odysseys in the battle against viruses such as COVID-19. A systematic review was conducted on whether the N95 masks could help improve our cardiovascular health. Our data sources included PubMed, Medline and Scopus. Eleven studies met the eligibility criteria to be included in the review. N95 mask usage led to increased reports of dyspnoea, however, no significant effect was seen on blood pressure. N95 masks also showed improvement in aortic parameters. While encouraging results were yielded, further focussed studies on the use of N95 masks and the effect on various cardiovascular parameters would help strengthen the association.

What were the historical reasons for the resistance to recognizing airborne transmission during the COVID-19 pandemic?

The question of whether SARS-CoV-2 is mainly transmitted by droplets or aerosols has been highly controversial. We sought to explain this controversy through a historical analysis of transmission research in other diseases. For most of human history, the dominant paradigm was that many diseases were carried by the air, often over long distances and in a phantasmagorical way. This miasmatic paradigm was challenged in the mid to late 19th century with the rise of germ theory, and as diseases such as cholera, puerperal fever, and malaria were found to actually transmit in other ways. Motivated by his views on the importance of contact/droplet infection, and the resistance he encountered from the remaining influence of miasma theory, prominent public health official Charles Chapin in 1910 helped initiate a successful paradigm shift, deeming airborne transmission most unlikely. This new paradigm became dominant. However, the lack of understanding of aerosols led to systematic errors in the interpretation of research evidence on transmission pathways. For the next five decades, airborne transmission was considered of negligible or minor importance for all major respiratory diseases, until a demonstration of airborne transmission of tuberculosis (which had been mistakenly thought to be transmitted by droplets) in 1962. The contact/droplet paradigm remained dominant, and only a few diseases were widely accepted as airborne before COVID-19: those that were clearly transmitted to people not in the same room. The acceleration of interdisciplinary research inspired by the COVID-19 pandemic has shown that airborne transmission is a major mode of transmission for this disease, and is likely to be significant for many respiratory infectious diseases.

Mask Use for Athletes: A Systematic Review of Safety and Performance Outcomes

CONTEXT

With the current Centers for Disease Control and Prevention recommendations for mask use to minimize transmission of coronavirus 2019 (COVID-19) coupled with concern for future pandemics that would require mask wearing, providing data-driven guidance with respect to athletic performance is essential.

OBJECTIVE

The purpose of this study was to perform a systematic review of existing literature on the use of face masks while exercising to assess the physiologic effects of face masks worn during athletic activities.

DATA SOURCES

A systematic review was conducted of studies on face mask use during exercise according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Potential studies were identified through searches of MEDLINE, Embase, Cochrane CENTRAL and CINAHL databases.

STUDY SELECTION

Screening was completed independently by 2 coauthors who sought to identify studies that described the effects of oronasal mask use, if any, on sports/exercise/physical activity, for any age, gender, or level of sport. Articles describing mask effects without exercise, articles published before 1980, and non-English language studies were excluded.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Data extraction focused on physiologic parameters measured during physical activity performed while wearing a face mask.

RESULTS

Twenty-two articles met all inclusion criteria. Study analysis revealed that the use of masks in healthy volunteers during exercise had no significant effect on physiologic parameters measured including heart rate (HR), respiratory rate (RR), oxygen saturation, and perceived exertion. Of the studies that investigated N95 masks in the healthy adult population, 2 reported modest changes in RR and maximum power output indicative of decreased athletic performance when subjects were exercising at maximum effort. Similar findings were seen in studies of subpopulations including children and pregnant women.

CONCLUSION

Available data suggest that healthy individuals can perform moderate-to-vigorous exercise while wearing a face mask without experiencing changes in HR, RR, and oxygen saturation that would compromise individual safety or athletic performance. In the specific situation in which an N95 mask is worn, maximum power generated may be impaired.

WHAT IS KNOWN ABOUT THE SUBJECT

To date, there has been no systematic review of the existing literature to provide a clear consensus on whether face mask use significantly impacts athletic performance. Mask use has been demonstrated safe in the workplace; however, the use of face masks during exercise has not been examined on a large scale, particularly with respect to physiologic parameters.

WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE

This analysis highlights that available data suggest that healthy individuals can perform heavy exercise in face masks with minimal physiologic changes. This is the first systematic review of studies analyzing exercise use wearing masks. With the evidence presented here commonly cited concerns about both safety and performance decrements with mask use during physical activities may be allayed.

Applying the CDC Science Impact Framework to the results of the National Institute for Occupational Safety and Health and the Bureau of Labor Statistics 2001 survey of respirator use and practices

During 2001-2002, the National Institute for Occupational Safety and Health (NIOSH), at the United States Centers for Disease Control and Prevention, collaborated with the Bureau of Labor Statistics (BLS) at the United States Department of Labor to conduct a voluntary survey of U.S. employers regarding the use of respiratory protective devices. In 2003, the survey results were jointly published by NIOSH and BLS. This study highlights and evaluates the scientific impact of the 2001-2002 survey by using the Science Impact Framework which provides a historical tracking method with five domains of influence. The authors conducted interviews with original project management as well as a thorough document review and qualitative content analysis of published papers, books, presentations, and other relevant print media. A semi-structured and cross-vetted coding was applied across the five domains: Disseminating Science, Creating Awareness, Catalyzing Action, Effecting Change, and Shaping the Future. The 2001-2002 survey findings greatly enhanced understanding and awareness of respirator use in occupational settings within the United States. It also led to similar surveys in other countries, regulatory initiatives by the Occupational Safety and Health Administration and Mine Safety and Health Administration, and ultimately to a renewed partnership between NIOSH and BLS to collect contemporary estimates of respirator use in the workplace within the United States.

The Cardiopulmonary Effects of Medical Masks and Filtering Facepiece Respirators on Healthy Health Care Workers in the Emergency Department: A Prospective Cohort Study

Background

International COVID-19 guidelines recommend that health care workers (HCWs) wear filtering facepiece (FFP) respirators to reduce exposure risk. However, there are concerns about FFP respirators causing hypercapnia via rebreathing carbon dioxide (CO₂). Most previous studies measured the physiological effects of FFP respirators on treadmills or while resting, and such measurements may not reflect the physiological changes of HCWs working in the emergency department (ED).

Objective

Our aim was to evaluate the physiological and clinical impacts of FFP type II (FFP2) respirators on HCWs during 2 h of their day shift in the ED.

Methods

We included emergency HCWs in this prospective cohort study. We measured end-tidal CO₂ (ETCO₂), mean arterial pressure (MAP), respiratory rate (RR), and heart rate values and dyspnea scores of subjects at two time points. The first measurements were carried out with medical masks while resting. Subjects then began their day shift in the ED with medical mask plus FFP2 respirator. We called subjects after 2 h for the second measurement.

Results

The median age of 153 healthy volunteers was 24.0 years (interquartile range 24.0–25.0 years). Subjects’ MAP, RR, and ETCO₂ values and dyspnea scores were significantly higher after 2 h. Median ETCO₂ values increased from 36.4 to 38.8 mm Hg. None of the subjects had hypercapnia symptoms, hypoxia, or other adverse effects.

Conclusion

We did not observe any clinical reflection of these changes in physiological values. Thus, we evaluated these changes to be clinically insignificant. We found that it is safe for healthy HCWs to wear medical masks plus FFP2 respirators during a 2-h working shift in the ED.

Bayesian network meta-analysis of face masks' impact on human physiology

Several concerns regarding the safety of face masks use have been propounded in public opinion. The objective of this review is to examine if these concerns find support in the literature by providing a comprehensive overview of physiological responses to the use of face masks. We have performed a systematic review, pairwise and network meta-analyses to investigate physiological responses to the use of face masks. The study has been registered with PROSPERO (C RD42020224791). Obtained results were screened using our exclusion and inclusion criteria. Meta-analyses were performed using the GeMTC and meta R packages. We have identified 26 studies meeting our inclusion and exclusion criteria, encompassing 751 participants. The use of face masks was not associated with significant changes in pulsoxymetrically measured oxygen saturation, even during maximal-effort exercises. The only significant physiological responses to the use of face masks during low-intensity activities were a slight increase in heart rate, mildly elevated partial pressure of carbon dioxide (not meeting criteria for hypercarbia), increased temperature of facial skin covered by the mask, and subsequent increase of the score in the rating of heat perception, with N95 filtering facepiece respirators having a greater effect than surgical masks. In high-intensity conditions, the use of face masks was associated with decreased oxygen uptake, ventilation, and RR. Face masks are safe to use and do not cause significant alterations in human physiology. The increase in heart rate stems most likely from increased respiratory work required to overcome breathing resistance. The increase in carbon dioxide is too small to be clinically relevant. An increased rating of heat perception when using face masks results from higher temperature of facial skin covered by the mask.

Personal Interventions to Reduce Exposure to Outdoor Air Pollution

Unhealthy levels of air pollution are breathed by billions of people worldwide, and air pollution is the leading environmental cause of death and disability globally. Efforts to reduce air pollution at its many sources have had limited success, and in many areas of the world, poor air quality continues to worsen. Personal interventions to reduce exposure to air pollution include avoiding sources, staying indoors, filtering indoor air, using face masks, and limiting physical activity when and where air pollution levels are elevated. The effectiveness of these interventions varies widely with circumstances and conditions of use. Compared with upstream reduction or control of emissions, personal interventions place burdens and risk of adverse unintended consequences on individuals. We review evidence regarding the balance of benefits and potential harms of personal interventions for reducing exposure to outdoor air pollution, which merit careful consideration before making public health recommendations with regard to who should use personal interventions and where, when, and how they should be used. Expected final online publication date for the Annual Review of Public Health, Volume 43 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The Impact of Ubiquitous Face Masks and Filtering Face Piece Application During Rest, Work and Exercise on Gas Exchange, Pulmonary Function and Physical Performance: A Systematic Review with Meta-analysis

BACKGROUND

Protection against airborne infection is currently, due to the COVID-19-associated restrictions, ubiquitously applied during public transport use, work and leisure time. Increased carbon dioxide re-inhalation and breathing resistance may result thereof and, in turn, may negatively impact metabolism and performance.

OBJECTIVES

To deduce the impact of the surgical mask and filtering face piece type 2 (FFP2) or N95 respirator application on gas exchange (pulse-derived oxygen saturation (SpO₂), carbon dioxide partial pressure (PCO₂), carbon dioxide exhalation (VCO₂) and oxygen uptake (VO₂)), pulmonary function (respiratory rate and ventilation) and physical performance (heart rate HR, peak power output W_peak).

METHODS

Systematic review with meta-analysis. Literature available in Medline/Pubmed, the Cochrane Library and the Web of Knowledge with the last search on the 6^th of May 2021. Eligibility criteria: Randomised controlled parallel group or crossover trials (RCT), full-text availability, comparison of the acute effects of ≥ 1 intervention (surgical mask or FFP2/N95 application) to a control/comparator condition (i.e. no mask wearing). Participants were required to be healthy humans and > 16 years of age without conditions or illnesses influencing pulmonary function or metabolism. Risk of bias was rated using the crossover extension of the Cochrane risk of bias assessment tool II. Standardised mean differences (SMD, Hedges' g) with 95% confidence intervals (CI) were calculated, overall and for subgroups based on mask and exercise type, as pooled effect size estimators in our random-effects meta-analysis.

RESULTS

Of the 1499 records retrieved, 14 RCTs (all crossover trials, high risk of bias) with 25 independent intervention arms (effect sizes per outcome) on 246 participants were included. Masks led to a decrease in SpO₂ during vigorous intensity exercise (6 effect sizes; SMD = - 0.40 [95% CI: - 0.70, - 0.09], mostly attributed to FFP2/N95) and to a SpO₂-increase during rest (5 effect sizes; SMD = 0.34 [95% CI: 0.04, 0.64]); no general effect of mask wearing on SpO₂ occurred (21 effect sizes, SMD = 0.34 [95% CI: 0.04, 0.64]). Wearing a mask led to a general oxygen uptake decrease (5 effect sizes, SMD = - 0.44 [95% CI: - 0.75, - 0.14]), to slower respiratory rates (15 effect sizes, SMD = - 0.25 [95% CI: - 0.44, - 0.06]) and to a decreased ventilation (11 effect sizes, SMD = - 0.43 [95% CI: - 0.74, - 0.12]). Heart rate (25 effect sizes; SMD = 0.05 [95% CI: - 0.09, 0.19]), W_peak (9 effect sizes; SMD = - 0.12 [95% CI: - 0.39, 0.15]), PCO₂ (11 effect sizes; SMD = 0.07 [95% CI: - 0.14, 0.29]) and VCO₂ (4 effect sizes, SMD = - 0.30 [95% CI: - 0.71, 0.10]) were not different to the control, either in total or dependent on mask type or physical activity status.

CONCLUSION

The number of crossover-RCT studies was low and the designs displayed a high risk of bias. The within-mask- and -intensity-homogeneous effects on gas exchange kinetics indicated larger detrimental effects during exhausting physical activities. Pulse-derived oxygen saturation was increased during rest when a mask was applied, whereas wearing a mask during exhausting exercise led to decreased oxygen saturation. Breathing frequency and ventilation adaptations were not related to exercise intensity. FFP2/N95 and, to a lesser extent, surgical mask application negatively impacted the capacity for gas exchange and pulmonary function but not the peak physical performance. Registration: Prospero registration number: CRD42021244634.

The tiny effects of respiratory masks on physiological, subjective, and behavioral measures under mental load in a randomized controlled trial

Since the outbreak of the coronavirus disease (COVID-19), face coverings are recommended to diminish person-to-person transmission of the SARS-CoV-2 virus. Some public debates concern claims regarding risks caused by wearing face masks, like, e.g., decreased blood oxygen levels and impaired cognitive capabilities. The present, pre-registered study aims to contribute clarity by delivering a direct comparison of wearing an N95 respirator and wearing no face covering. We focused on a demanding situation to show that cognitive efficacy and individual states are equivalent in both conditions. We conducted a randomized-controlled crossover trial with 44 participants. Participants performed the task while wearing an N95 FFR versus wearing none. We measured physiological (blood oxygen saturation and heart rate variability), behavioral (parameters of performance in the task), and subjective (perceived mental load) data to substantiate our assumption as broadly as possible. We analyzed data regarding both statistical equivalence and differences. All of the investigated dimensions showed statistical equivalence given our pre-registered equivalence boundaries. None of the dimensions showed a significant difference between wearing an FFR and not wearing an FFR.Trial Registration: Preregistered with the Open Science Framework: https://osf.io/c2xp5 (15/11/2020). Retrospectively registered with German Clinical Trials Register: DRKS00024806 (18/03/2021).

Personal Interventions for Reducing Exposure and Risk for Outdoor Air Pollution: An Official American Thoracic Society Workshop Report

Poor air quality affects the health and wellbeing of large populations around the globe. Although source controls are the most effective approaches for improving air quality and reducing health risks, individuals can also take actions to reduce their personal exposure by staying indoors, reducing physical activity, altering modes of transportation, filtering indoor air, and using respirators and other types of face masks. A synthesis of available evidence on the efficacy, effectiveness, and potential adverse effects or unintended consequences of personal interventions for air pollution is needed by clinicians to assist patients and the public in making informed decisions about use of these interventions. To address this need, the American Thoracic Society convened a workshop in May of 2018 to bring together a multidisciplinary group of international experts to review the current state of knowledge about personal interventions for air pollution and important considerations when helping patients and the general public to make decisions about how best to protect themselves. From these discussions, recommendations were made regarding when, where, how, and for whom to consider personal interventions. In addition to the efficacy and safety of the various interventions, the committee considered evidence regarding the identification of patients at greatest risk, the reliability of air quality indices, the communication challenges, and the ethical and equity considerations that arise when discussing personal interventions to reduce exposure and risk from outdoor air pollution.

Does wearing double surgical masks during the COVID-19 pandemic reduce maternal oxygen saturation in term pregnant women?: A prospective study

Purpose

This study aimed to compare the effects of using single and double surgical masks (SM) on maternal oxygen saturation in pregnant women.

Methods

In this prospective study, single or double SM were worn by term pregnant women who applied for routine controls. The vital signs of the participants such as oxygen saturation, pulse, respiratory rate, fever, systolic and diastolic blood pressure were measured at admission and 30 min later.

Results

There were 223 participants in the single SM group and 231 participants in the double SM group. Thirty minutes after putting on the mask, there was no significant difference in the proportion of patients whose oxygen saturation fell below 95 (3.6 vs 5.6%, p = 0.301). No significant difference was observed between the admission and 30 min oxygen saturation levels of the pregnant women in the single SM group. However, maternal oxygen saturation after 30 min of the pregnant women in the double SM group was significantly lower (97.4 ± 1.1 vs 96.6 ± 1.3, p < 0.001). No significant changes were observed in the vital signs of either groups.

Conclusion

When using double SM, oxygen saturation is significantly reduced compared to pre-mask values. Nevertheless, it seems difficult to say that these decreases have clinical significance.

Is a Mask That Covers the Mouth and Nose Free from Undesirable Side Effects in Everyday Use and Free of Potential Hazards?

Many countries introduced the requirement to wear masks in public spaces for containing SARS-CoV-2 making it commonplace in 2020. Up until now, there has been no comprehensive investigation as to the adverse health effects masks can cause. The aim was to find, test, evaluate and compile scientifically proven related side effects of wearing masks. For a quantitative evaluation, 44 mostly experimental studies were referenced, and for a substantive evaluation, 65 publications were found. The literature revealed relevant adverse effects of masks in numerous disciplines. In this paper, we refer to the psychological and physical deterioration as well as multiple symptoms described because of their consistent, recurrent and uniform presentation from different disciplines as a Mask-Induced Exhaustion Syndrome (MIES). We objectified evaluation evidenced changes in respiratory physiology of mask wearers with significant correlation of O2 drop and fatigue (p < 0.05), a clustered co-occurrence of respiratory impairment and O2 drop (67%), N95 mask and CO2 rise (82%), N95 mask and O2 drop (72%), N95 mask and headache (60%), respiratory impairment and temperature rise (88%), but also temperature rise and moisture (100%) under the masks. Extended mask-wearing by the general population could lead to relevant effects and consequences in many medical fields.

The effect of mask use on maternal oxygen saturation in term pregnancies during the COVID-19 process

OBJECTIVES

Our aim was to evaluate the effect of standard surgical and N-95 respiratory mask use on maternal oxygen saturation, vital signs and result on non-stress tests in term pregnancies.

METHODS

It is a prospective observational study. The study included healthy, not in labor, singleton pregnant women of 370/7-410/7 weeks who were applied to our hospital for routine obstetric control examination between March 1, 2020, and August 31, 2020. Patients were randomised by coin toss method. Oxygen saturation, systolic, and diastolic arterial blood pressure, pulse, respiratory rate, and temperature of pregnant women using surgical masks and respiratory masks were measured before and after the non-stress test. The tolerance of the masks was also evaluated. Student's t-test was used for variables showing parametric distribution and the Mann Whitney U-test was used for non-parametric tests. The categorical variables between the groups was analyzed by using the Chi square test or Fisher Exact test. The statistical significance level was taken as p<0.05 in all tests.

RESULTS

A total of 297 pregnant women using masks were included in the study. The effect of mask type on oxygen saturation before and after the non-stress test was found to be significant (97.1±1.8 corresponds to 95.3±2.6 for the surgical mask, p=0.0001; 97.8±1.7 corresponds to 93.7±2.0 for the respiratory mask, p=0.0001). Mask tolerance of patients using respiratory masks was significantly higher than those using surgical masks (mean 8, 1-10, p=0.0001).

CONCLUSIONS

Surgical mask and respiratory mask usage decreased significantly in oxygen saturation in term pregnancies.

Sustainable Resumption of Cardiac Catheterization Laboratory Procedures, and the Importance of Testing, During Endemic COVID-19

PURPOSE

As second and third waves of the COVID-19 pandemic challenge healthcare in North America and Europe once again, we analyze the impact of the first wave on routine elective cardiovascular care, and the differential COVID risk emerging within our patient groups and staff.

PERSPECTIVE

We describe the need to sustainably resume, and temporarily expand, routine elective cardiac services in the face of resurgent COVID-19. Some, but not all, cardiac patient groups are particularly vulnerable to adverse outcomes following COVID-19 infection. We explore mitigation measures at the institutional level to increase resilience within cardiac services to enable them to operate deep into subsequent waves of COVID infection which place unprecedented demands on intensive care infrastructure. As measures to eradicate the virus appear to have failed in many countries, and vaccine roll-out will take many months we take the view that the threat imposed by endemic COVID-19 alters the way elective procedural care should be offered to cardiovascular patients.

CONCLUSION

Our patients are at definite risk from their cardiovascular disease, and a return to suspension of proven prognostic interventional treatments on an elective basis - the default for the first wave - must be avoided at all costs.

Health effects of wildfire smoke in children and public health tools: a narrative review

Wildfire smoke is an increasing environmental health threat to which children are particularly vulnerable, for both physiologic and behavioral reasons. To address the need for improved public health messaging this review summarizes current knowledge and knowledge gaps in the health effects of wildfire smoke in children, as well as tools for public health response aimed at children, including consideration of low-cost sensor data, respirators, and exposures in school environments. There is an established literature of health effects in children from components of ambient air pollution, which are also present in wildfire smoke, and an emerging literature on the effects of wildfire smoke, particularly for respiratory outcomes. Low-cost particulate sensors demonstrate the spatial variability of pollution, including wildfire smoke, where children live and play. Surgical masks and respirators can provide limited protection for children during wildfire events, with expected decreases of roughly 20%  and 80% for surgical masks and N95 respirators, respectively. Schools should improve filtration to reduce exposure of our nation's children to smoke during wildfire events. The evidence base described may help clinical and public health authorities provide accurate information to families to improve their decision making.

Consequences of FFP3 mask usage on venous blood gases

Objectives/hypothesis

To investigate the effect of FFP3 mask usage on venous blood gases (VBG) and some subjective symptoms

Methods

VBG analyses and subjective symptom questionary were obtained from 15 healthcare proffesionals before and after 4-h FFP3 mask usage.

Results

Wearing an FFP3 mask for 4 hours did not change any venous blood gas parameters between pre- and post-values, statistically. According to an 8-symptom questionary, only nausea did not show any significance. Headache, lightheadedness, visual difficulties, shortness of breath, palpitation, confusion, and difficult communication showed statistically significant difference between pre and post values.

Conclusion

Four-hour use of FFP3 mask did not cause any significant VBG change. Although the participants complained about some subjective symptoms, this study indicated that long-term use of FFP3 mask did not cause any significant discomforts, and it was well tolerated.

Face masks: benefits and risks during the COVID-19 crisis

Background

The German government has made it mandatory to wear respiratory masks covering mouth and nose (MNC) as an effective strategy to fight SARS-CoV-2 infections. In many countries, this directive has been extended on shopping malls or public transportation. The aim of this paper is to critically analyze the statutory regulation to wear protective masks during the COVID-19 crisis from a medical standpoint.

Methods

We performed an extensive query of the most recent publications addressing the prevention of viral infections including the use of face masks in the community as a method to prevent the spread of the infection. We addressed the issues of practicability, professional use, and acceptability based on the community and the environment where the user resided.

Results

Upon our critical review of the available literature, we found only weak evidence for wearing a face mask as an efficient hygienic tool to prevent the spread of a viral infection. However, the use of MNC seems to be linked to relevant protection during close contact scenarios by limiting pathogen-containing aerosol and liquid droplet dissemination. Importantly, we found evidence for significant respiratory compromise in patients with severe obstructive pulmonary disease, secondary to the development of hypercapnia. This could also happen in patients with lung infections, with or without SARS-CoV-2.

Conclusion

Epidemiologists currently emphasize that wearing MNC will effectively interrupt airborne infections in the community. The government and the politicians have followed these recommendations and used them to both advise and, in some cases, mandate the general population to wear MNC in public locations. Overall, the results seem to suggest that there are some clinically relevant scenarios where the use of MNC necessitates more defined recommendations. Our critical evaluation of the literature both highlights the protective effects of certain types of face masks in defined risk groups, and emphasizes their potential risks.

N95 Filtering Facepiece Respirator Use during Pregnancy: A Systematic Review

OBJECTIVE

This study was aimed to systematically review the use of filtering facepiece respirators, such asN95 masks, during pregnancy.

STUDY DESIGN

A comprehensive search for primary literature using Medline, Embase, Scopus, Web of Science, and ClinicalTrials.gov was conducted from inception until April 2020 to find articles reporting outcomes of pregnant women using filtering facepiece respirator (FFR). Studies were selected if they included the use of FFR in pregnant women and reported an outcome of interest including physiologic changes (heart rate, respiratory rate, pulse oximetry, and fetal heart rate tracing) or subjective measures (thermal or exertional discomfort or fit). The Newcastle-Ottawa Quality Assessment scale was used to assess the risk of bias. The main outcome was to describe the physiologic changes in pregnant women compared with nonpregnant women. Due to the small number of studies and heterogeneity of reported outcomes a meta-analysis was not conducted. Results of the studies were synthesized into a summary of evidence table.

RESULTS

We identified four studies, three cohort studies and one crossover study, comprising 42 women using FFR during pregnancy. Risk of bias was judged to be low. Studies were consistent in showing no significant increase in maternal heart rate, respiratory rate, oxygen saturation, and fetal heart rate between pregnant and nonpregnant women using N95 FFRs for short durations. Repeat fit testing was not supported for women gaining the recommended amount of weight during pregnancy. No evidence was found to reach conclusions about prolonged N95 FFR use in pregnancy.

CONCLUSION

Limited duration N95 FFR use during pregnancy is unlikely to impart risk to the pregnant women or her fetus.

KEY POINTS

· Limited N95 use unlikely to impart risk to pregnant woman/fetus.. · Prolonged N95 use in pregnancy is unstudied.. · Repeat fit testing in pregnancy likely unnecessary..

Coronavirus disease 2019 (COVID-19) pandemic and pregnancy

The current coronavirus disease 2019 (COVID-19) pneumonia pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading globally at an accelerated rate, with a basic reproduction number (R0) of 2-2.5, indicating that 2-3 persons will be infected from an index patient. A serious public health emergency, it is particularly deadly in vulnerable populations and communities in which healthcare providers are insufficiently prepared to manage the infection. As of March 16, 2020, there are more than 180,000 confirmed cases of COVID-19 worldwide, with more than 7000 related deaths. The SARS-CoV-2 virus has been isolated from asymptomatic individuals, and affected patients continue to be infectious 2 weeks after cessation of symptoms. The substantial morbidity and socioeconomic impact have necessitated drastic measures across all continents, including nationwide lockdowns and border closures. Pregnant women and their fetuses represent a high-risk population during infectious disease outbreaks. To date, the outcomes of 55 pregnant women infected with COVID-19 and 46 neonates have been reported in the literature, with no definite evidence of vertical transmission. Physiological and mechanical changes in pregnancy increase susceptibility to infections in general, particularly when the cardiorespiratory system is affected, and encourage rapid progression to respiratory failure in the gravida. Furthermore, the pregnancy bias toward T-helper 2 (Th2) system dominance, which protects the fetus, leaves the mother vulnerable to viral infections, which are more effectively contained by the Th1 system. These unique challenges mandate an integrated approach to pregnancies affected by SARS-CoV-2. Here we present a review of COVID-19 in pregnancy, bringing together the various factors integral to the understanding of pathophysiology and susceptibility, diagnostic challenges with real-time reverse transcription polymerase chain reaction (RT-PCR) assays, therapeutic controversies, intrauterine transmission, and maternal-fetal complications. We discuss the latest options in antiviral therapy and vaccine development, including the novel use of chloroquine in the management of COVID-19. Fetal surveillance, in view of the predisposition to growth restriction and special considerations during labor and delivery, is addressed. In addition, we focus on keeping frontline obstetric care providers safe while continuing to provide essential services. Our clinical service model is built around the principles of workplace segregation, responsible social distancing, containment of cross-infection to healthcare providers, judicious use of personal protective equipment, and telemedicine. Our aim is to share a framework that can be adopted by tertiary maternity units managing pregnant women in the flux of a pandemic while maintaining the safety of the patient and healthcare provider at its core.

Emergency cesarean section performed in a patient with confirmed severe acute respiratory syndrome Coronavirus-2 -a case report

Background

Since the first case of severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) occurred in Wuhan in December 2019, the virus has spread globally. The World Health Organization declared the virus outbreak a pandemic on March 11, 2020. On January 19, 2020, a 35-year-old woman who returned from China was confirmed as the first SARS-CoV-2 infected case in Korea. Since then, it has spread all over Korea.

Case

We report the first case of a SARS-CoV-2 positive woman delivering a baby through cesarean section at 37⁺⁶ weeks of pregnancy in the Republic of Korea.

Conclusions

This case suggested that negative pressure operating room, skillful medical team, and enhanced personal protective equipment including N95 masks, surgical cap, double gown, double gloves, shoe covers, and powered air-purifying respirator are required at the hospital for safe delivery in such a case.

Wearable devices for remote vital signs monitoring in the outpatient setting: an overview of the field

Early detection of physiological deterioration has been shown to improve patient outcomes. Due to recent improvements in technology, comprehensive outpatient vital signs monitoring is now possible. This is the first review to collate information on all wearable devices on the market for outpatient physiological monitoring.

A scoping review was undertaken. The monitors reviewed were limited to those that can function in the outpatient setting with minimal restrictions on the patient’s normal lifestyle, while measuring any or all of the vital signs: heart rate, ECG, oxygen saturation, respiration rate, blood pressure and temperature.

A total of 270 papers were included in the review. Thirty wearable monitors were examined: 6 patches, 3 clothing-based monitors, 4 chest straps, 2 upper arm bands and 15 wristbands. The monitoring of vital signs in the outpatient setting is a developing field with differing levels of evidence for each monitor. The most common clinical application was heart rate monitoring. Blood pressure and oxygen saturation measurements were the least common applications. There is a need for clinical validation studies in the outpatient setting to prove the potential of many of the monitors identified.

Research in this area is in its infancy. Future research should look at aggregating the results of validity and reliability and patient outcome studies for each monitor and between different devices. This would provide a more holistic overview of the potential for the clinical use of each device.

The effects of facemasks on airway inflammation and endothelial dysfunction in healthy young adults: a double-blind, randomized, controlled crossover study

Background

Facemasks are increasingly worn during air pollution episodes in China, but their protective effects are poorly understood. We aimed to evaluate the filtration efficiencies of N95 facemasks and the cardiopulmonary benefits associated with wearing facemasks during episodes of pollution.

Results

We measured the filtration efficiencies of particles in ambient air of six types of N95 facemasks with a manikin headform. The most effective one was used in a double-blind, randomized, controlled crossover study, involving 15 healthy young adults, conducted during 2 days of severe pollution in Beijing, China. Subjects were asked to walk along a busy-traffic road for 2 h wearing authentic or sham N95 facemasks. Clinical tests were performed four times to determine changes in the levels of biomarkers of airway inflammation, endothelial dysfunction, and oxidative stress within 24 h after exposure.

The facemasks removed 48–75% of number concentrations of ambient air particles between 5.6 and 560 nm in diameter. After adjustments for multiple comparison, the exhaled nitric oxide level and the levels of interleukin-1α, interleukin-1β, and interleukin-6 in exhaled breath condensate increased significantly in all subjects; however, the increases in those wearing authentic facemasks were statistically significantly lower than in the sham group. No significant between-group difference was evident in the urinary creatinine-corrected malondialdehyde level. In arterial stiffness indicators, the ejection duration of subjects wearing authentic facemasks was higher after exposure compared to the sham group; no significant between-group difference was found in augmentation pressure or the augmentation index.

Conclusions

In young healthy adults, N95 facemasks partially reduced acute particle-associated airway inflammation, but neither systemic oxidative stress nor endothelial dysfunction improved significantly. The clinical significance of these findings long-term remains to be determined.

Trial registration

The trial registration number (TRN) for this study is ChiCTR1800016099, which was retrospectively registered on May 11, 2018.

Electronic supplementary material

The online version of this article (10.1186/s12989-018-0266-0) contains supplementary material, which is available to authorized users.

Emergency cesarean section in an epidemic of the middle east respiratory syndrome: a case report

Only a few reports have been published on women with an infectious respiratory viral pathogen, such as Middle East Respiratory Syndrome (MERS) Coronavirus delivering a baby. A laboratory confirmed case of MERS was reported during a MERS outbreak in the Republic of Korea in a woman at gestational week 35 + 4. She recovered, and delivered a healthy baby by emergency cesarean section (C-sec). We present the clinical course and the emergency C-sec in a pregnant woman with MERS.

"Will my work affect my pregnancy?" Resources for anticipating and answering patients' questions

BACKGROUND

Authoritative information on occupational reproductive hazards is scarce and complex because exposure levels vary, multiple exposures may be present, and the reproductive toxicity of many agents remains unknown. For these reasons, women's health providers may find it challenging to effectively address workplace reproductive health issues with their patients who are pregnant, breast-feeding, or considering pregnancy. Reproductive epidemiologists at the Centers for Disease Control and Prevention National Institute for Occupational Safety and Health answered >200 public requests for occupational reproductive health information during 2009 through 2013. The most frequent occupations represented were health care (41%) and laboratory work (18%). The most common requests for exposure information concerned solvents (14%), anesthetic gases (10%), formaldehyde (7%), infectious agents in laboratories (7%) or health care settings (7%), and physical agents (14%), including ionizing radiation (6%). Information for developing workplace policies or guidelines was sought by 12% of the requestors. Occupational exposure effects on breast-feeding were an increasing concern among working women. Based on information developed in response to these requestors, information is provided for discussing workplace exposures with patients, assessing potential workplace reproductive hazards, and helping patients determine the best options for safe work in pregnancy. Appendices provide resources to address specific occupational exposures, employee groups, personal protective equipment, breast-feeding, and workplace regulations regarding work and pregnancy. These tools can help identify those most at risk of occupational reproductive hazards and improve workers' reproductive health. The information can also be used to inform research priorities and assist the development of workplace reproductive health policies.

The pregnant healthcare worker: fact and fiction

PURPOSE OF REVIEW

A pregnant healthcare worker (HCW) may be at risk of occupational exposure to pathogens associated with increased maternal morbidity and mortality as well as perinatal complications. In this article, we review recent literature on infectious diseases commonly encountered in the healthcare setting and of highest concern for a pregnant HCW, focusing on prevention and management of exposures.

RECENT FINDINGS

Pregnancy does not seem to be an independent risk factor for occupationally acquired infectious diseases. Vaccination and standard precautions continue to be the most effective means of preventing transmission to HCWs. Pandemic 2009 influenza A (H1N1) is associated with increased risk of fetal death, highlighting the importance of influenza vaccination. A recent meta-analysis highlights the safety of influenza vaccination during pregnancy. New treatments for hepatitis C have not been studied in pregnancy but pose an important area for research and advancement. Cytomegalovirus immunoglobulin may play a role in postexposure prophylaxis but recent results are inconclusive.

SUMMARY

Primary prevention with vaccination and use of appropriate infection control precautions is imperative for prevention of occupationally acquired infectious diseases. Pregnant HCWs with occupational exposure to communicable diseases should be evaluated immediately for appropriate postexposure prophylaxis and followed for development of active infection.

Respiratory consequences of N95-type Mask usage in pregnant healthcare workers-a controlled clinical study

Background

Outbreaks of emerging infectious diseases have led to guidelines recommending the routine use of N95 respirators for healthcare workers, many of whom are women of childbearing age. The respiratory effects of prolonged respirator use on pregnant women are unclear although there has been no definite evidence of harm from past use.

Methods

We conducted a two-phase controlled clinical study on healthy pregnant women between 27 to 32 weeks gestation. In phase I, energy expenditure corresponding to the workload of routine nursing tasks was determined. In phase II, pulmonary function of 20 subjects was measured whilst at rest and exercising to the predetermined workload while breathing ambient air first, then breathing through N95-mask materials.

Results

Exercising at 3 MET while breathing through N95-mask materials reduced mean tidal volume (TV) by 23.0 % (95 % CI −33.5 % to −10.5 %, p < 0.001) and lowered minute ventilation (VE) by 25.8 % (95 % CI −34.2 % to −15.8 %, p < 0.001), with no significant change in breathing frequency compared to breathing ambient air. Volumes of oxygen consumption (VO₂) and carbon dioxide expired (VCO₂) were also significantly reduced; VO₂ by 13.8 % (95 % CI −24.2 % to −3 %, p = 0.013) and VCO₂ by 17.7 %, (95 % CI −28.1 % to −8.6 %, p = 0.001). Although no changes in the inspired oxygen and carbon dioxide concentrations were demonstrated, breathing through N95-mask materials during low intensity work (3 MET) reduced expired oxygen concentration by 3.2 % (95 % CI: −4.1 % to −2.2 %, p < 0.001), and increased expired carbon dioxide by 8.9 % (95 % CI: 6.9 % to 13.1 %; p <0.001) suggesting an increase in metabolism. There were however no changes in the maternal and fetal heart rates, finger-tip capillary lactate levels and oxygen saturation and rating of perceived exertion at the work intensity investigated.

Conclusions

Breathing through N95 mask materials have been shown to impede gaseous exchange and impose an additional workload on the metabolic system of pregnant healthcare workers, and this needs to be taken into consideration in guidelines for respirator use. The benefits of using N95 mask to prevent serious emerging infectious diseases should be weighed against potential respiratory consequences associated with extended N95 respirator usage.

Trial Registration

The study was registered at clinicaltrials.gov, identifier NCT00265926.

Effect of external airflow resistive load on postural and exercise-associated cardiovascular and pulmonary responses in pregnancy: a case control study

BACKGROUND

Facial coverings (e.g., balaclavas, niqabs, medical/surgical masks, respirators, etc.), that impose low levels of airflow resistive loads, are worn by millions of pregnant women worldwide, but little data exist addressing their impact on pregnancy-associated cardiovascular and pulmonary responses.

METHODS

16 pregnant and 16 non-pregnant women were monitored physiologically (heart rate, blood pressure, mean arterial pressure, total peripheral resistance, stroke volume, cardiac output, oxygen saturation, transcutaneous carbon dioxide, fetal heart rate) and subjectively (exertion) for 1 h of mixed sedentary postural activity (sitting, standing) and moderate exercise (bicycle ergometer) with and without wearing N95 filtering facepiece respirators with filter resistive loads of 94.1 Pa (9.6 mm H2O) - 119.6 Pa (12.2 mm H2O) pressure.

RESULTS

The external airflow resistive loads were associated with increases in diastolic pressure (p = 0.004), mean arterial pressure (p = 0.01), and subjective exertion score (p < 0.001) of all study subjects. No significant differences were noted with the external resistive loads between the pregnant and non-pregnant groups for any cardiovascular, pulmonary and subjective variable over 1 h.

CONCLUSIONS

Low external airflow resistive loads, during combined sedentary postural activity and moderate exercise over 1 h, were associated with increases in the diastolic and mean arterial pressures of all study subjects, but pregnancy itself was not associated with any significant differences in physiologic or subjective responses to the external airway resistive loads utilized in the study.

Effect of Pregnancy Upon Facial Anthropometrics and Respirator Fit Testing

Workers required to wear respirators must undergo additional respirator fit testing if a significant change in body weight occurs. Approximately 10% of working women of reproductive age will be pregnant and experience a significant change in weight, yet the effect of pregnancy-associated weight gain on respirator fit is unknown. Cephalo-facial anthropometric measurements and quantitative fit testing of N95 filtering facepiece respirators (N95 FFR) of 15 pregnant women and 15 matched, non-pregnant women were undertaken for comparisons between the groups. There were no significant differences between pregnant and non-pregnant women with respect to cephalo-facial anthropometric measurements or N95 FFR quantitative fit tests. Healthy pregnant workers, who adhere to the recommended weight gain limits of pregnancy, are unlikely to experience an increase in cephalo-facial dimensions that would mandate additional N95 FFR fit testing above that which is normally required on an annual basis.

Effect of wearing an N95 respirator on infrared tympanic membrane temperature measurements

To determine the impact of wearing an N95 filtering facepiece respirator (N95 FFR) on tympanic temperature measurements. TMT measurements, with and without wearing an N95 filtering facepiece respirator (N95 FFR) were obtained at the onset and termination of 1 h of treadmill exercise in 21 subjects, and at staggered time intervals (0, 20, 40, 60 min) during combined sedentary activity and exercise of another 46 subjects, to determine any effect on TMT. A total of 877 TMT measurements were obtained that demonstrated a mean TMT increase of 0.05 °C in the first study group (p = 0.04) and a 0.19 °C decrease in the second study group (p < 0.001) with the wearing of an N95 FFR, both of which were lower than controls. Wearing an N95 FFR for 1 h, at different levels of activity, results in significantly lower TMT values than not wearing an N95 FFR, but the magnitude of the changes would likely have minimal clinical significance.