Respiratory Health Associated with Systemic Metal Exposure in Post 9/11 Veterans in the Department of Veterans Affairs Toxic Embedded Fragment Registry.

OBJECTIVE: Adverse respiratory outcomes in post-9/11 Veterans with elevated urinary metal measures and enrolled in the VA's Toxic Embedded Fragment registry were compared to those without elevated urinary metals. METHODS: Veterans completed questionnaires, pulmonary physiology tests (pulmonary function and oscillometry) and provided urine samples for analysis of 13 metals. Respiratory symptoms, diagnoses and physiology measures were compared in Veterans with ≥1 urine metal elevation to those without metal elevations, adjusted for covariates, including smoking. RESULTS: Among 402 study participants, 24% had elevated urine metals, often just exceeding upper limits of reference values. Compared to Veterans without elevated metals, those with elevated metals had had higher FEV1 values but similar frequencies of respiratory symptoms and diagnoses and abnormalities on pulmonary physiology tests. CONCLUSIONS: Mild systemic metal elevations in post 9/11 Veterans are not associated with adverse respiratory health outcomes.

Mortality of older construction and craft workers employed at Department of Energy (DOE) nuclear sites: Follow-up through 2021.

BACKGROUND: To determine if construction and trades workers formerly employed at US Department of Energy (DOE) nuclear weapons sites are at significant risk for occupational diseases, we studied the mortality experience of participants in the Building Trades National Medical Screening Program (BTMed). METHODS: The cohort included 26,922 participants enrolled between 1998 and 2021 and 8367 deaths. Standardized mortality ratios were calculated based on US death rates. Cox models compared construction workers (n = 22,747; 7487 deaths) to two nonconstruction subpopulations: administrative, scientific and security workers (n = 1894; 330 deaths), and all other nonconstruction workers (n = 2218; 550 deaths). RESULTS: Mortality was elevated for all causes, all cancers, cancers of the trachea, bronchus, lung, kidneys, and lymphatic and hematopoietic system, mesothelioma, chronic obstructive pulmonary disease (COPD), asbestosis, transportation injuries, and other injuries, particularly accidental poisonings. There were 167 deaths from coronavirus disease 2019 (COVID-19), which was lower than expected using US death rates. Overall cause-specific mortality was significantly higher among construction workers than for internal comparison groups. CONCLUSIONS: Construction workers employed at DOE sites have a significantly increased risk for occupational illnesses. Apart from COVID-19 deaths, this update: (1) found that mortality among construction workers is significantly elevated compared to the US population and significantly higher than in the internal comparison populations, and (2) confirmed excess risk for these workers for first employment after 1990. Cancer mortality risks are similar to the cancers identified for DOE compensation from radiation exposures. The high lung cancer risk supports the value of early lung cancer detection. Continued medical surveillance is important.

Elastomeric half-mask respirator disinfection practices among healthcare personnel.

BACKGROUND: Disposable N95 respirator shortages during the COVID-19 and 2009 H1N1 influenza pandemics highlighted the need for reusable alternatives, such as elastomeric half-mask respirators (EHMRs). Two US medical organizations deployed reusable EHMRs during the COVID-19 response. In addition to wipe-based disinfection following patient care episodes expected per local policies at both organizations, postshift centralized cleaning and disinfection (C&D) was expected at one site (A), permitting shared-pool EHMR use, and optional at the other (Site B), where EHMRs were issued to individuals. Using a survey, we evaluated disinfection practices reported by EHMR users and predictors of disinfection behaviors and perceptions. METHODS: Surveys assessed EHMR disinfection practices, occupational characteristics, EHMR use frequency, training, and individual-issue versus shared-pool EHMR use. RESULTS: Of 1080 EHMR users completing the survey, 76% reported that they disinfect the EHMR after each patient encounter, which was the expected practice at both sites. Increasing EHMR use, recall of disinfection training, and work in intensive care or emergency settings significantly influenced higher reporting of this practice. 36% of respondents reported using centralized C&D, although reporting was higher at the site (A) where this was expected (53%). Confidence in cleanliness of the EHMR following centralized C&D was not influenced by individual versus shared-pool EHMR issue. CONCLUSIONS: Most EHMR users reported adherence with expected post-care individual-based disinfection of EHMRs but did not necessarily use standardized, centralized C&D. Future efforts to limit reliance on behavior related to respirator disinfection may improve EHMR implementation in healthcare to avert dependence on single-use, disposable N95 respirators.

Examining the Impact of Elastomeric Half Mask Respirator Knowledge and User Barriers on Safety Climate Perceptions in Health Care Settings.

BACKGROUND: Availability of personal protective equipment (PPE) and its effective use may influence safety climate perceptions among health care personnel (HCP). It is unclear how health care organizations can leverage the effective use of respiratory protection to engage in continuous improvement of their safety climate, which can inform opportunities for employee education and engagement. METHODS: After using an elastomeric half mask respirator (EHMR) as their primary form of respiratory protection for several months, 1,080 HCP provided feedback in an electronic survey about respiratory protection training, confidence in EHMR use, barriers during use, and perceived safety climate. Ordinal logistic regressions were used as nonlinear models to test relationships between these variables. FINDINGS: We observed that an increase in user confidence (p < .013), training content (p < .001), training formats (p < .001), and a decrease in EHMR barriers (p < .001) were associated with a statistically significant increase in proactive safety climate. In the second model, an increase in user confidence (p < .006) and training content (p < .001), and a decrease in barriers (p < .001), was associated with a statistically significant increase in compliant safety climate. CONCLUSIONS/APPLICATION TO PRACTICE: HCP EHMR confidence was positively associated with safety climate perceptions, underscoring the value of competency building by respiratory protection leaders prior to implementation. Because fewer barriers experienced while using an EHMR were associated with a more positive perception of safety climate, it is important to first communicate with end users about potential barriers and, second, to continue research with end users and manufacturers to improve the design of EHMRs moving forward.

The Department of Veterans' Affairs Depleted Uranium Cohort in the Time of COVID-19: Translating a Traditional Surveillance Protocol to a Telehealth Platform.

OBJECTIVE: In 2021, 37 members of a cohort of depleted uranium-exposed Gulf War I veterans were evaluated using a protocol tailored to accommodate COVID-19 safety practices on a telehealth platform. METHODS: Individual elements of the legacy protocol were reviewed for urgency and feasibility of inclusion in a modified, telehealth platform. RESULTS: The redesigned protocol included a participant readiness for telehealth assessment, nurse and physician telehealth visits, collection of usual health questionnaires, and urine collections for exposure monitoring for uranium and other fragment-related metal measures. CONCLUSIONS: Despite some limitations in scope, the telehealth platform permitted a visual "visit" with surveillance participants who expressed a high comfort level with the format. The telehealth platform has apparent utility for occupational surveillance and should be explored as a standard approach for surveillance outside of public health emergencies.

Economic Impact of Insufficient and Disturbed Sleep in the Workplace.

OBJECTIVE: Insufficient and disturbed sleep are associated with significant morbidity among working-age adults. Poor sleep results in negative health outcomes and increases economic costs to employers. The current systematic review surveyed the peer-reviewed scientific literature and aggregated scientific evidence of sleep-related economic burdens borne by employers. METHODS: A systematic review was performed to identify peer-reviewed, English language studies evaluating the economic impact of insufficient and disturbed sleep among adult employee populations. An exhaustive literature search was performed using keywords related to sleep, economics, and the workplace. Included were scientific studies (randomized controlled trials, cohort and case control studies, cross-sectional and longitudinal studies) examining specific employee populations with relevant sleep and economic outcomes. Each included study was evaluated for risk of bias and relevant data was extracted and summarized. RESULTS: Sleep problems among employee populations are associated with worsened workplace outcomes, such as presenteeism, absenteeism, and accidents. Sleep problems also increased costs to employers, ranging from US$322 to US$1967 per employee. Interventions to improve sleep, such as the use of blue-light filtering glasses, strategic shift scheduling, and targeted interventions to treat insomnia, may improve workplace outcomes and reduce costs. CONCLUSIONS: This review synthesizes the existing data regarding the negative impacts of insufficient and disturbed sleep on the workplace, suggesting that employers have an economic stake in their employees' sleep. TRIAL REGISTRATION: PROSPERO: CRD42021224212.

Restrictive spirometry pattern among construction trade workers.

BACKGROUND: Spirometry-based studies of occupational lung disease have mostly focused on obstructive or mixed obstructive/restrictive outcomes. We wanted to determine if restrictive spirometry pattern (RSP) is associated with occupation and increased mortality. METHODS: Study participants included 18,145 workers with demographic and smoking data and repeatable spirometry. The mortality analysis cohort included 15,445 workers with known vital status and cause of death through December 31, 2016. Stratified analyses explored RSP prevalence by demographic and clinical variables and trade. Log-binomial regression models explored RSP risk factors while controlling for important confounders such as smoking, obesity, and comorbidities. Cox regression models explored mortality risk by spirometry category. RESULTS: Prevalence of RSP was very high (28.6%). Mortality hazard ratios for RSP were 1.50 for all causes, 1.86 for cardiovascular diseases, 2.31 for respiratory diseases, and 1.66 for lung cancer. All construction trades except painters, machinists, and roofers had significantly elevated risk for RSP compared to our internal reference group. RSP was significantly associated with both parenchymal and pleural changes seen by chest X-ray. CONCLUSIONS: Construction trade workers are at significantly increased risk for RSP independent of obesity. Individuals with RSP are at increased risk for all-cause mortality as well as mortality attributable to respiratory diseases, cardiovascular diseases, and lung cancer. RSP deserves greater attention in occupational medicine and epidemiology.

Consensus Statements on Deployment-Related Respiratory Disease, Inclusive of Constrictive Bronchiolitis: A Modified Delphi Study.

BACKGROUND: The diagnosis of constrictive bronchiolitis (CB) in previously deployed individuals, and evaluation of respiratory symptoms more broadly, presents considerable challenges, including using consistent histopathologic criteria and clinical assessments. RESEARCH QUESTION: What are the recommended diagnostic workup and associated terminology of respiratory symptoms in previously deployed individuals? STUDY DESIGN AND METHODS: Nineteen experts participated in a three-round modified Delphi study, ranking their level of agreement for each statement with an a priori definition of consensus. Additionally, rank-order voting on the recommended diagnostic approach and terminology was performed. RESULTS: Twenty-five of 28 statements reached consensus, including the definition of CB as a histologic pattern of lung injury that occurs in some previously deployed individuals while recognizing the importance of considering alternative diagnoses. Consensus statements also identified a diagnostic approach for the previously deployed individual with respiratory symptoms, distinguishing assessments best performed at a local or specialty referral center. Also, deployment-related respiratory disease (DRRD) was proposed as a broad term to subsume a wide range of potential syndromes and conditions identified through noninvasive evaluation or when surgical lung biopsy reveals evidence of multicompartmental lung injury that may include CB. INTERPRETATION: Using a modified Delphi technique, consensus statements provide a clinical approach to possible CB in previously deployed individuals. Use of DRRD provides a broad descriptor encompassing a range of postdeployment respiratory findings. Additional follow-up of individuals with DRRD is needed to assess disease progression and to define other features of its natural history, which could inform physicians better and lead to evolution in this nosology.

Surface Contamination of Reusable Respirators and Face Shields During Care of Critically Ill COVID-19 Patients.

BACKGROUND: With the emergence of SARS-CoV-2, healthcare workers (HCW) have relied on reusable personal protective equipment (PPE), including respirators and face shields (FSs). The effectiveness of decontamination procedures outside experimental settings is unclear. We examined the prevalence of surface contamination on reusable PPE used by HCWs at a hospital incorporating daily centralized decontamination and post-use wiping by sampling for common pathogens. METHOD: Samples were collected from HCWs' CleanSpace Halo respirator face masks (FMs) and FSs at the start of shift, immediately after use, and after cleaning with disinfecting wipes. Samples were analyzed for pathogens using the Applied Biosystems™ TaqPath™ COVID-19 Combo Kit and ThermoFisher TaqMan Array Card. Patient charts were reviewed for clinical correlation. FINDINGS: Of the 89 samples, 51 from FMs and 38 from FSs, none tested positive for SARS-CoV-2, despite 58 being obtained from PPE used in the care of patients with COVID-19, many with recent aerosol-generating procedures. Four samples tested positive (4.5%) for Staphylococcus aureus, two each from FMs and FSs. FMs that tested positive were not worn concurrently with FSs that tested positive. The FM and FS samples testing positive were worn in the care of patients without diagnosed S. aureus infection. No FMs tested positive following wipe-based disinfection, but both positive FS samples were found after disinfection wiping. CONCLUSION/APPLICATION TO PRACTICE: Contamination of reusable PPE appears uncommon, especially with SARS-CoV-2, when regular decontamination programs are in place. The rare presence of S. aureus highlights the importance of doffing procedures and hand hygiene by HCW to prevent surface contamination.

Tolerability, user acceptance and preference for a novel reusable respirator among health care workers.

BACKGROUND: The CleanSpace Technology Halo respirator combines a clear face mask and a powered air supply, without belts or hoses. Although providing higher protection than other respirators used in health care, user acceptance of this device has not been assessed with validated tools. METHODS: We surveyed healthcare workers (HCWs) within a US medical system using Halo respirators in 2021. Subjects completed 3 surveys over 8 weeks, which included the Respirator Comfort, Wearing Experience, and Function Instrument (R-COMFI), a validated tool to assess respirator tolerability. The survey included additional questions about user acceptability and respirator preference. Responses were evaluated for change over time and for significant predictors. RESULTS: Of 113 HCWs who completed the initial survey (29% response rate), mean ± SD R-COMFI score was 9.1± 5.1, (scale 0-47, lower = more tolerable) and did not change over time (P = .42). Fewer years in healthcare significantly predicted better R-COMFI score (P = .01). Many users preferred Halo in both usual care (45%-52%) and care of patients with COVID-19 (60%-64%). DISCUSSION: Halo respirators received favorable tolerability scores by HCWs, who often preferred them, especially during care of patients with COVID-19. CONCLUSIONS: Given demand for respirator use in health care, the innovative design provides higher protection than other respirators with a favorable user experience.

Postdeployment Respiratory Health: The Roles of the Airborne Hazards and Open Burn Pit Registry and the Post-Deployment Cardiopulmonary Evaluation Network.

Background: Following deployment to the Southwest Asia theater of operations and Afghanistan, many service members and veterans report respiratory symptoms and concerns about their military and environmental exposures. The US Department of Veterans Affairs (VA) established the national Airborne Hazards and Open Burn Pit Registry (AHOBPR) in 2014 to help better understand long-term health conditions that may be related to these exposures. Observations: The AHOBPR provides an online questionnaire and optional health evaluation performed by a primary care or environmental health clinician. The clinical evaluation provides an opportunity for the service member or veteran to talk with a health care professional about their symptoms, exposures, and potential treatment. Data derived from questionnaire responses and health evaluations facilitate medical surveillance and research. The VA also established a network of specialists, referred to as the Post-Deployment Cardiopulmonary Evaluation Network (PDCEN). The PDCEN identifies veterans within the AHOBPR who self-report certain conditions or have unexplained dyspnea and conducts comprehensive diagnostic evaluations. Primary objectives of PDCEN evaluations are to define respiratory and related conditions that are present, determine whether conditions are related to deployment, and work with the veteran's clinician to identify treatments and/or follow-up care to improve their health. We utilize a case example to illustrate the role of the primary care practitioner in connecting veterans to PDCEN clinical evaluations. Conclusions: AHOBPR clinical evaluations represent an initial step to better understand postdeployment health conditions. The PDCEN clinical evaluation extends the AHOBPR evaluation by providing specialty care for certain veterans requiring more comprehensive evaluation while systematically collecting and analyzing clinical data to advance the field.

Self-reported respiratory outcomes associated with blast exposure in post 9/11 veterans.

BACKGROUND: Blast lung overpressure has received interest as a cause of chronic respiratory disease in Service members who deployed in support of U.S. military operations in Southwest Asia and Afghanistan since 2001. We studied whether veterans who experienced blast exposure report more chronic respiratory symptoms and diagnoses compared to deployed veterans who did not. METHODS: 9,000 veterans included in the Department of Veterans Affairs Toxic Embedded Fragment Registry were invited to complete a survey assessing chronic respiratory symptoms, diagnoses, and exposures. Blast exposure was assessed using the Brief Traumatic Brain Injury Screen and by presence of other symptoms such as blast-induced loss of consciousness. RESULTS: Participants (n = 2147) were predominantly <40 years old, served in the Army, and injured on average 12.8 years previously. 91% reported blast exposure. Blast-exposed veterans were significantly more likely to report cough (OR 1.8), wheeze (OR 2.4), and dyspnea (OR 1.8), even after adjustment for covariates including smoking and occupational exposures to dust, fume, and gas. Veterans reporting higher severity of blast impact, such as traumatic brain injury or loss of consciousness, were more likely to report cough, wheeze, or dyspnea. Veterans with higher severity of blast impact by multiple measures were also more likely to report having COPD. Those reporting a physician-diagnosis of traumatic brain injury were significantly more likely to report having both asthma (OR 1.5) and COPD (OR 1.5). CONCLUSIONS: Blast exposure is associated with respiratory symptoms and COPD. Respiratory system evaluation may warrant inclusion as a standard part of barotrauma health assessment.

Military exposures and lung cancer in United States veterans.

Lung cancer screening begins at age 50, with yearly low dose computed tomography (LDCT) scans until age 80, for patients determined to be high risk due to tobacco smoking. Veterans serving from World War II to the Gulf War are now at the age where LDCT is recommended. This recommendation from the United States Preventative Service Task Force includes patients who have a 20-pack year tobacco history and currently smoke or quit within the last 15 years. This recommendation does not consider additional risk factors such as exposures to lung carcinogens. We discuss unique operational and occupational exposures encountered while serving in the armed forces, which may potentially increase the risk of lung cancers in the Veteran population. The additional risk of lung cancer due to military exposure history is unclear and more work is needed to identify and quantify risk at an individual level. Increasing awareness at the provider level regarding the carcinogenic exposures encountered may allow a larger population of Veterans, not meeting traditional LDCT criteria, to benefit from lung cancer screening.

Beryllium disease among construction trade workers at Department of Energy nuclear sites: A follow-up.

BACKGROUND: Construction workers at U.S. Department of Energy (DOE) nuclear weapons facilities are screened to identify DOE-related occupational illnesses, including beryllium sensitization (BeS) and chronic beryllium disease (CBD). The study objectives were to estimate beryllium disease risks and the CBD claims acceptance rate in the energy workers' benefits program. METHODS: Workers diagnosed with BeS via beryllium lymphocyte proliferation test (BeLPT) included in screening examinations were interviewed about subsequent diagnosis of CBD. We estimated the proportion who developed CBD based on the ratio of CBD cases, based on self-reported compensation claim status, to all workers with BeS interviewed. We used stratified analyses to explore trends in disease frequency by age, race, sex, DOE employment duration, site, trade group, and cigarette smoking history. RESULTS: Between 1998 and 2020, 21,854 workers received a BeLPT; 262 (1.20%) had BeS (two abnormals or one abnormal plus one borderline test); 212 (0.97%) had a single abnormal BeLPT. Of 177 BeS workers interviewed, 35 (19.8%) reported an accepted CBD compensation claim. The claims acceptance rate among BeS workers increased with years of DOE employment, from 8.4% with <5 years to 33.3% for >25 or more years. Five of 68 interviewed workers with a single positive BeLPT reported CBD claim acceptance; an additional CBD case was confirmed by chart review (8.8%). CONCLUSIONS: Years of DOE work predict the risk of developing CBD among those sensitized and getting a claim for CBD accepted. Ongoing surveillance and increased awareness of the risk of beryllium exposure and CBD as an occupational disease among construction workers are needed.

Characteristics Associated With Health Care Worker Knowledge and Confidence in Elastomeric Half-Mask Respirator Use.

OBJECTIVE: This study evaluated health care workers' (HCWs') knowledge and confidence in using elastomeric half-mask respirator (EHMR) attributes known to influence usage. METHODS: Health care workers were surveyed regarding their EHMR donning and doffing experience. Respondents were categorized into competency categories based on their scores. Category differences were analyzed using χ 2 and multiple logistic regression. RESULTS: Seventy-two percent showed high levels of EHMR donning and doffing knowledge and confidence (mastery); however, 21% had greater confidence than knowledge (misinformed). Respiratory therapists had greater odds of mastery than other HCWs ( P < 0.05), whereas those working in medical/surgical and pediatric units had greater odds of doubt than other HCWs ( P < 0.01). CONCLUSIONS: Although most HCWs show high knowledge and confidence with EHMR use, strategies to confirm respirator use competency may ensure greater HCWs protection.

Respiratory Protection Perceptions among Malian Health Workers: Insights from the Health Belief Model.

Reusable respiratory protective devices called elastomeric respirators have demonstrated their effectiveness and acceptability in well-resourced healthcare settings. Using standard qualitative research methods, we explored the feasibility of elastomeric respirator use in low- and middle-income countries (LMIC). We conducted interviews and focus groups with a convenience sample of health workers at one clinical center in Mali. Participants were users of elastomeric and/or traditional N95 respirators, their supervisors, and program leaders. Interview transcripts of participants were analyzed using a priori constructs from the Health Belief Model (HBM) and a previous study about healthcare respirator use. In addition to HBM constructs, the team identified two additional constructs impacting uptake of respirator use (system-level factors and cultural factors). Together, these framed the perceptions of Malian health workers and highlighted both facilitators of and barriers to respirator use uptake. As needs for respiratory protection from airborne infectious hazards become more commonly recognized, elastomeric respirators may be a sustainable and economic solution for health worker protection in LMIC.

Demystifying idiopathic interstitial pneumonia: time for more etiology-focused nomenclature in interstitial lung disease.

INTRODUCTION: A major focus of interstitial lung disease (ILD) has centered on disorders termed idiopathic interstitial pneumonias (IIPs) which include, among others, idiopathic pulmonary fibrosis, idiopathic nonspecific interstitial pneumonia, cryptogenic organizing pneumonia, and respiratory bronchiolitis-interstitial lung disease. AREAS COVERED: We review the radiologic and histologic patterns for the nine disorders classified by multidisciplinary approach as IIP, and describe the remarkable amount of published epidemiologic, translational, and molecular studies demonstrating their associations with numerous yet definitive environmental exposures, occupational exposures, pulmonary diseases, systemic diseases, medication toxicities, and genetic variants. EXPERT OPINION: In the 21st century, these disorders termed IIPs are rarely idiopathic, but rather are well-described radiologic and histologic patterns of lung injury that are associated with a wide array of diverse etiologies. Accordingly, the idiopathic nomenclature is misleading and confusing, and may also promote a lack of inquisitiveness, suggesting the end rather than the beginning of a thorough diagnostic process to identify ILD etiology and initiate patient-centered management. A shift toward more etiology-focused nomenclature will be beneficial to all, including patients hoping for better life quality and disease outcome, general medicine and pulmonary physicians furthering their ILD knowledge, and expert ILD clinicians and researchers who are advancing the ILD field.

Spirometry testing for extracorporeal membrane oxygenation (ECMO) bridge to transplant patients.

PURPOSE: ECMO can provide a bridge to transplantation and improve survival for patients with advanced lung disease. Although pulmonary function testing (PFT) is an important component of the lung allocation score (LAS), it is not always feasible on patients requiring ECMO. While generally safe, PFT testing has contraindications and is not recommended in unstable patients. Currently there are no recommendations regarding the performance of spirometry in ECMO patients. STUDY DESIGN: and Methods: We reviewed data on five patients with advanced lung disease requiring ECMO-bridge to transplant. After careful consideration of the theoretical physiologic risks associated with forced expiratory maneuvers, bedside spirometry was performed in order to update the patients' LAS. RESULTS: All patients successfully completed three forced expiratory maneuvers in the seated position with a bedside spirometer. Vital signs and ECMO flow were stable during testing and without complication. In 2 patients who had both a LAS pre and post spirometry, the LAS increased by 3-5 points. CONCLUSION: Spirometry results are pivotal to organ allocation under current organ sharing protocols. This case series demonstrates that bedside spirometry testing may be performed safely in patients on ECMO awaiting lung transplantation without appreciable side effects, leading to a more accurate LAS score.

Physiological Impacts of Surgical Mask Coverage of Elastomeric Half-mask Respirator Exhalation Valves in Healthcare Workers.

OBJECTIVES: Elastomeric half-mask respirator (EHMR) use in healthcare increased significantly during the COVID-19 pandemic. Concern for potential release of infectious aerosols from EHMR exhalation valves prompted recommendations to cover them with surgical masks (SMs), thereby improving source control. The physiological and subjective effects of wearing a SM over the exhalation valve of an EHMR, however, are unknown. METHODS: Twelve healthy healthcare worker volunteers completed a 30-min series of simulated healthcare-related tasks, including resting, talking, walking, and bending, proning and supinating a weighted manikin, and performing cardiopulmonary resuscitation. This series recurred three times with different mask configurations-SM only, EHMR only, or EHMR with SM covering the exhalation valve. A transcutaneous sensor continuously measured carbon dioxide (tcPCO2), oxygen saturation (SpO2), and heart rate (HR) from each subject. Subjects scored their rates of perceived exertion (RPE) and levels of discomfort after each round. Physiological parameters and subjective scores were analyzed using mixed linear models with a fixed effect for mask type, activity, age, body mass index (BMI), and gender. Analysis also tested for interaction between mask type and activity. RESULTS: Physiological parameters remained within normal ranges for all mask configurations but varied by task. Statistically significant but small decreases in mean tcPCO2 (37.17 versus 37.88 mmHg, P < 0.001) and SpO2 (97.74 versus 97.94%, P < 0.001) were associated with wearing EHMR with SM over the exhalation valve compared with EHMR alone. Mean HR did not differ between these mask configurations. Wearing SM only was associated with lower RPE and level of discomfort compared with EHMR, but these subjective scores did not differ when comparing EHMR with SM to EHMR only. Age, BMI, and gender had no significant effect on any outcomes. CONCLUSIONS: Wearing a SM over an EHMR did not produce clinically significant changes in tcPCO2, SpO2, or HR compared with uncovered EHMR during healthcare-related tasks. Covered EHMR use also did not affect perceived exertion or discomfort compared with uncovered EHMR use. Covering the exhalation valve of an EHMR with a SM for source control purposes can be done safely.

Urine miRNAs as potential biomarkers for systemic reactions induced by exposure to embedded metal.

Aim: Explore the potential of urine microRNAs as biomarkers that may reflect the biological responses to pure metals embedded in skeletal muscle over time. Materials & methods: We tested a panel of military-relevant metals embedded in the gastrocnemius muscles of 3-month-old, male, Sprague-Dawley rats (n = 8/group) for a duration of 1, 3, 6 and 12 months, and performed small RNA-sequencing on the urine samples. Results: Results provide potential tissue targets affected by metal exposure and a list of unique or common urine microRNA biomarkers indicative of exposure to various metals, highlighting a complex systemic response. Conclusion: We have identified a panel of miRNAs as potential urine biomarkers to reflect the complex systemic response to embedded metal exposure.