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1.
Sci Rep ; 12(1): 17926, 2022 Oct 26.
Article in English | MEDLINE | ID: covidwho-2087297

ABSTRACT

Being the proximal matrix, breath offers immediate metabolic outlook of respiratory infections. However, high viral load in exhalations imposes higher transmission risk that needs improved methods for safe and repeatable analysis. Here, we have advanced the state-of-the-art methods for real-time and offline mass-spectrometry based analysis of exhaled volatile organic compounds (VOCs) under SARS-CoV-2 and/or similar respiratory conditions. To reduce infection risk, the general experimental setups for direct and offline breath sampling are modified. Certain mainstream and side-stream viral filters are examined for direct and lab-based applications. Confounders/contributions from filters and optimum operational conditions are assessed. We observed immediate effects of infection safety mandates on breath biomarker profiles. Main-stream filters induced physiological and analytical effects. Side-stream filters caused only systematic analytical effects. Observed substance specific effects partly depended on compound's origin and properties, sampling flow and respiratory rate. For offline samples, storage time, -conditions and -temperature were crucial. Our methods provided repeatable conditions for point-of-care and lab-based breath analysis with low risk of disease transmission. Besides breath VOCs profiling in spontaneously breathing subjects at the screening scenario of COVID-19/similar test centres, our methods and protocols are applicable for moderately/severely ill (even mechanically-ventilated) and highly contagious patients at the intensive care.


Subject(s)
COVID-19 , Volatile Organic Compounds , Humans , Volatile Organic Compounds/analysis , COVID-19/diagnosis , SARS-CoV-2 , Breath Tests/methods , Exhalation , Biomarkers/analysis , Monitoring, Physiologic
2.
J Investig Allergol Clin Immunol ; 32(5): 417-418, 2022 10.
Article in English | MEDLINE | ID: covidwho-2067428
4.
Expert Rev Respir Med ; 16(10): 1093-1099, 2022 Oct.
Article in English | MEDLINE | ID: covidwho-2051063

ABSTRACT

BACKGROUND: Residual alveolar inflammation seems to be paramount in post-COVID pathophysiology. Currently, we still lack a reliable marker to detect and track alveolar phlogosis in these patients. Exhaled Breath Condensate (EBC) pH has robust evidences highlighting its correlation with lung phlogosis in various diseases. We aim to define the reliability of alveolar and bronchial EBC pH in the assessment and in the follow up of post-COVID-related inflammation. RESEARCH DESIGN AND METHODS: We enrolled 10 patients previously hospitalized due to COVID-19 pneumonia. We performed a complete follow-up after 3 months and 6 months from discharge. Each visit included routine blood tests, arterial blood gas analysis, 6-minute walking test, spirometry, diffusing capacity and body plethysmography. Finally, bronchial and alveolar EBC were collected at the end of each visit. RESULTS: Alveolar EBC pH was significantly lower than bronchial EBC pH at T1, alveolar EBC pH tended to be more acid after 3 months from hospital discharge compared to the same sample 6 months later. Serum inflammatory biomarkers showed no significant differences from T1 to T2. Alveolar EBC pH was positively correlated with neutrophil-lymphocyte ratio. CONCLUSIONS: Collecting EBC pH could help to understand pathophysiologic mechanism as well as monitoring alveolar inflammation in the post-COVID syndrome.


Subject(s)
Breath Tests , COVID-19 , Humans , Reproducibility of Results , Hydrogen-Ion Concentration , Biomarkers/analysis , Inflammation/diagnosis , Disease Progression , Exhalation/physiology
5.
Sci Rep ; 12(1): 15990, 2022 09 26.
Article in English | MEDLINE | ID: covidwho-2050537

ABSTRACT

The COVID-19 pandemic has attracted numerous research studies because of its impact on society and the economy. The pandemic has led to progress in the development of diagnostic methods, utilizing the polymerase chain reaction (PCR) as the gold standard for coronavirus SARS-CoV-2 detection. Numerous tests can be used at home within 15 min or so but of with lower accuracy than PCR. There is still a need for point-of-care tests available for mass daily screening of large crowds in airports, schools, and stadiums. The same problem exists with fast and continuous monitoring of patients during their medical treatment. The rapid methods can use exhaled breath analysis which is non-invasive and delivers the result quite fast. Electronic nose can detect a cocktail of volatile organic com-pounds (VOCs) induced by virus infection and disturbed metabolism in the human body. In our exploratory studies, we present the results of COVID-19 detection in a local hospital by applying the developed electronic setup utilising commercial VOC gas sensors. We consider the technical problems noticed during the reported studies and affecting the detection results. We believe that our studies help to advance the proposed technique to limit the spread of COVID-19 and similar viral infections.


Subject(s)
COVID-19 , Volatile Organic Compounds , Breath Tests/methods , COVID-19/diagnosis , Electronic Nose , Exhalation , Humans , Pandemics , SARS-CoV-2 , Volatile Organic Compounds/analysis
6.
PLoS One ; 17(6): e0265816, 2022.
Article in English | MEDLINE | ID: covidwho-2021634

ABSTRACT

We probed the transmission of COVID-19 by applying an airborne transmission model to five well-documented case studies-a Washington state church choir, a Korean call center, a Korean exercise class, and two different Chinese bus trips. For all events the likely index patients were pre-symptomatic or mildly symptomatic, which is when infective patients are most likely to interact with large groups of people. Applying the model to those events yields results that suggest the following: (1) transmission was airborne; (2) superspreading events do not require an index patient with an unusually high viral load; (3) the viral loads for all of the index patients were of the same order of magnitude and consistent with experimentally measured values for patients at the onset of symptoms, even though viral loads across the population vary by a factor of >108. In particular we used a Wells-Riley exposure model to calculate q, the total average number of infectious quanta inhaled by a person at the event. Given the q value for each event, the simple airborne transmission model was used to determined Sq, the rate at which the index patient exhaled infectious quanta and N0, the characteristic number of COVID-19 virions needed to induce infection. Despite the uncertainties in the values of some parameters of the superspreading events, all five events yielded (N0∼300-2,000 virions), which is similar to published values for influenza. Finally, this work describes the conditions under which similar methods can provide actionable information on the transmission of other viruses.


Subject(s)
COVID-19 , Influenza, Human , COVID-19/epidemiology , Exhalation , Humans , Serologic Tests , Viral Load
9.
PLoS One ; 17(8): e0270765, 2022.
Article in English | MEDLINE | ID: covidwho-1993474

ABSTRACT

Face masks are used to protect the wearer from harmful external air and to prevent transmission of viruses from air exhaled by potentially infected wearers to the surrounding people. In this study, we examined the potential utility of masks for collecting viruses contained in exhaled breath and detected the collected viruses via various molecular tests. Using KF94 masks, the inner electrostatic filter was selected for virus collection, and an RNA extraction protocol was developed for the face mask. Virus detection in worn mask samples was performed using PCR and rolling circle amplification (RCA) tests and four different target genes (N, E, RdRp, and ORF1ab genes). The present study confirmed that the mask sample tests showed positive SARS-CoV-2 results, similar to the PCR tests using nasopharyngeal swab samples. In addition, the quantity of nucleic acid collected in the masks linearly increased with wearing time. These results suggest that samples for SARS-CoV-2 tests can be collected in a noninvasive, quick, and easy method by simply submitting worn masks from subjects, which can significantly reduce the hassle of waiting at airports or public places and concerns about cross-infection. In addition, it is expected that miniaturization technology will integrate PCR assays on face masks in the near future, and mask-based self-diagnosis would play a significant role in resolving the pandemic situation.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , Exhalation , Humans , Masks , Pandemics/prevention & control , SARS-CoV-2/genetics
10.
PLoS One ; 17(7): e0269925, 2022.
Article in English | MEDLINE | ID: covidwho-1963010

ABSTRACT

BACKGROUND: Portable breath ketone sensors may help people with Type 1 Diabetes Mellitus (T1DM) avoid episodes of diabetic ketoacidosis; however, the design features preferred by users have not been studied. We aimed to elucidate breath sensor design preferences of young people with T1DM (age 12 to 16) and their parents to inform the development of a breath ketone sensor prototype that would best suit their diabetes management needs. RESEARCH DESIGNS AND METHODS: To elicit foundational experiences from which design preference ideas could be generated, two commercially available breath ketone sensors, designed for ketogenic diet monitoring, were explored over one week by ten young people with T1DM. Participants interacted with the breath ketone sensing devices, and undertook blood ketone testing, at least twice daily for five days to simulate use within a real life and ambulatory care setting. Semi-structured interviews were conducted post-testing with the ten young participants and their caregivers (n = 10) to elicit preferences related to breath sensor design and use, and to inform the co-design of a breath ketone sensor prototype for use in T1DM self-management. We triangulated our data collection with key informant interviews with two diabetes educators working in pediatric care about their perspectives related to young people using breath ketone sensors. RESULTS: Participants acknowledged the non-invasiveness of breath sensors as compared to blood testing. Affordability, reliability and accuracy were identified as prerequisites for breath ketone sensors used for diabetes management. Design features valued by young people included portability, ease of use, sustainability, readability and suitability for use in public. The time required to use breath sensors was similar to that for blood testing. The requirement to maintain a 10-second breath exhalation posed a challenge for users. Diabetes educators highlighted the ease of use of breath devices especially for young people who tended to under-test using blood ketone strips. CONCLUSIONS: Breath ketone sensors for diabetes management have potential that may facilitate ketone testing in young people. Our study affirms features for young people that drive usability of breath sensors among this population, and provides a model of user preference assessment.


Subject(s)
Diabetes Mellitus, Type 1 , Diabetic Ketoacidosis , Adolescent , Child , Diabetes Mellitus, Type 1/therapy , Diabetic Ketoacidosis/diagnosis , Diabetic Ketoacidosis/therapy , Exhalation , Humans , Ketones , Reproducibility of Results
11.
Environ Sci Pollut Res Int ; 29(55): 83020-83044, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-1906478

ABSTRACT

It is well known that airborne transmission of COVID-19 in indoor spaces occurs through various respiratory activities: breathing, vocalizing, coughing, and sneezing. However, there is a complete lack of knowledge of its possible transmission through exhalations of e-cigarette aerosol (ECA), which is also a respiratory activity. E-cigarettes have become widely popular among smokers seeking a much safer way of nicotine consumption than smoking. Due to restrictive lockdown measures taken during the COVID-19 pandemic, many smokers and vapers (e-cigarette users) were confined to shared indoor spaces, making it necessary to assess the risk of SARS-CoV-2 virus aerial transmission through their exhalations. We summarize inferred knowledge of respiratory particles emission and transport through ECA, as well as a theoretical framework for explaining the visibility of exhaled ECA, which has safety implications and is absent in other respiratory activities (apart from smoking). We also summarize and briefly discuss the effects of new SARS-CoV-2 variants, vaccination rates, and environmental factors that may influence the spread of COVID-19. To estimate the risk of SARS-CoV-2 virus aerial transmission associated with vaping exhalations, we adapt a theoretical risk model that has been used to analyze the risks associated with other respiratory activities in shared indoor spaces. We consider home and restaurant scenarios, with natural and mechanical ventilation, with occupants wearing and not wearing face masks. We consider as "control case" or baseline risk scenario an indoor space (home and restaurant) where respiratory droplets and droplet nuclei are uniformly distributed and aerial contagion risk might originate exclusively from occupants exclusively rest breathing, assuming this to be the only (unavoidable) respiratory activity they all carry on. If an infected occupant uses an e-cigarette in a home or restaurant scenarios, bystanders not wearing face masks exposed to the resulting ECA expirations face a [Formula: see text] increase of risk of contagion with respect the control case. This relative added risk with respect to the control case becomes [Formula: see text] for high-intensity vaping, [Formula: see text], and over [Formula: see text] for speaking for various periods or coughing (all without vaping). Infectious emissions are significantly modified by mechanical ventilation, face mask usage, vaccination, and environmental factors, but given the lack of empiric evidence, we assume as a working hypothesis that all basic parameters of respiratory activities are equally (or roughly equally) affected by these factors. Hence, the relative risk percentages with respect to the control state should remain roughly the same under a wide range of varying conditions. By avoiding direct exposure to the visible exhaled vaping jet, wearers of commonly used face masks are well protected from respiratory droplets and droplet nuclei directly emitted by mask-less vapers. Compared to the control case of an already existing (unavoidable) risk from continuous breathing, vaping emissions in shared indoor spaces pose just a negligible additional risk of COVID-19 contagion. We consider that it is not necessary to take additional preventive measures beyond those already prescribed (1.5 m separation and wearing face masks) in order to protect bystanders from this contagion.


Subject(s)
COVID-19 , Electronic Nicotine Delivery Systems , Vaping , Humans , SARS-CoV-2 , Pandemics/prevention & control , Exhalation , Communicable Disease Control , Respiratory Aerosols and Droplets , Risk Assessment
12.
J Allergy Clin Immunol Pract ; 10(6): 1474-1484, 2022 06.
Article in English | MEDLINE | ID: covidwho-1878213

ABSTRACT

The COVID-19 pandemic has placed increased demands on the ability to safely perform pulmonary procedures in keeping with Centers for Disease Control and Prevention (CDC), American Thoracic Society (ATS), and the Occupational Safety and Health Administration (OSHA) recommendations. Accordingly, the American Academy of Allergy, Asthma & Immunology (AAAAI) Asthma Diagnosis and Treatment convened this work group to offer guidance. The work group is composed of specialist practitioners from academic and both large and small practices. Individuals with special expertise were assigned sections on spirometry, fractional exhaled nitric oxide, nebulized treatments, and methacholine challenge. The work group met periodically to achieve consensus. This resulting document has recommendations for the allergy/asthma/immunology health care setting based on available evidence including reference documents from the CDC, ATS, and OSHA.


Subject(s)
Asthma , COVID-19 , Hypersensitivity , Asthma/diagnosis , Asthma/epidemiology , Asthma/therapy , Breath Tests/methods , Exhalation , Humans , Nitric Oxide , Pandemics/prevention & control , Spirometry
13.
Respir Care ; 67(8): 899-905, 2022 08.
Article in English | MEDLINE | ID: covidwho-1863113

ABSTRACT

BACKGROUND: Methacholine challenge testing (MCT) is a common bronchoprovocation technique used to assess airway hyper-responsiveness. We previously demonstrated that the addition of a viral filter to the nebulizer exhalation limb substantially reduced expelled particles during MCT. Our aim was to evaluate whether this modification affects the delivered dose of methacholine. METHODS: A mechanical ventilator was connected to a lung simulator with breathing frequency 15 breaths/min, tidal volume 500 mL, inspiratory-expiratory ratio 1:1, with a sinusoidal waveform. We compared methacholine dose delivery using the Hudson Micro Mist or AeroEclipse II BAN nebulizers powered by either a dry gas source or a compressor system. A filter placed in line between the nebulizer and test lung was weighed before and after 1 min of nebulized methacholine delivery. Mean inhaled mass was measured with and without a viral filter on the exhalation limb. Dose delivery was calculated by multiplying the mean inhaled mass by the respirable fraction (particles < 5 µm) and inhalation time. Unpaired t test was used to compare methacholine dose delivery with and without viral filter placement. RESULTS: The addition of a viral filter did not significantly affect methacholine dose delivery across all devices tested. Using a 50-psi dry gas source, dose delivered with or without a viral filter did not differ with the Hudson (422.3 µg vs 282.0 µg, P = .11) or the AeroEclipse nebulizer (563.0 µg vs 657.6 µg, P = .59). Using the compressor, dose delivered with and without a viral filter did not differ with the Hudson (974.0 µg vs 868.0 µg, P = .03) or the AeroEclipse nebulizer (818.0 µg vs 628.5 µg, P = .42). CONCLUSIONS: The addition of a viral filter to the nebulizer exhalation limb did not affect methacholine dose during bronchoprovocation testing. Routine use of a viral filter should be considered to improve pulmonary function technician safety and infection control measures during the ongoing COVID-19 pandemic.


Subject(s)
COVID-19 , Exhalation , Administration, Inhalation , Aerosols , Albuterol , Bronchodilator Agents , Equipment Design , Humans , Methacholine Chloride , Nebulizers and Vaporizers , Pandemics
14.
Nitric Oxide ; 124: 68-73, 2022 07 01.
Article in English | MEDLINE | ID: covidwho-1851878

ABSTRACT

OBJECTIVE: To assess the feasibility of Fractional exhaled Nitric Oxide (FeNO) as a simple, non-invasive, cost-effective and portable biomarker and decision support tool for risk stratification of COVID-19 patients. METHODS: We conducted a single-center prospective cohort study of COVID-19 patients whose FeNO levels were measured upon ward admission by the Vivatmo-me handheld device. Demographics, COVID-19 symptoms, and relevant hospitalization details were retrieved from the hospital databases. The patients were divided into those discharged to recover at home and those who died during hospitalization or required admission to an intensive care unit, internal medicine ward, or dedicated facility (severe outcomes group). RESULTS: Fifty-six patients were enrolled. The only significant demographic difference between the severe outcomes patients (n = 14) and the home discharge patients (n = 42) was age (64.21 ± 13.97 vs. 53.98 ± 15.57 years, respectively, P = .04). The admission FeNO measurement was significantly lower in the former group compared with the latter group (15.86 ± 14.74 vs. 25.77 ± 13.79, parts per billion [PPB], respectively, P = .008). Time to severe outcome among patients with FeNO measurements ≤11.8 PPB was significantly shorter compared with patients whose FeNO measured >11.8 PPB (19.25 ± 2.96 vs. 24.41 ± 1.09 days, respectively, 95% confidence interval [CI] 1.06 to 4.25). An admission FeNO ≤11.8 PPB was a significant risk factor for severe outcomes (odds ratio = 12.8, 95% CI: 2.78 to 58.88, P = .001), with a receiver operating characteristics curve of 0.752. CONCLUSIONS: FeNO measurements by the Vivatmo-me handheld device can serve as a biomarker and COVID-19 support tool for medical teams. These easy-to-use, portable, and noninvasive devices may serve as valuable ED bedside tools during a pandemic.


Subject(s)
COVID-19 , Exhalation , Biomarkers , Breath Tests , COVID-19/diagnosis , Fractional Exhaled Nitric Oxide Testing , Humans , Nitric Oxide , Prospective Studies , Severity of Illness Index
15.
J Breath Res ; 16(3)2022 05 26.
Article in English | MEDLINE | ID: covidwho-1830923

ABSTRACT

Exhaled breath vapor contains hundreds of volatile organic compounds (VOCs), which are the byproducts of health and disease metabolism, and they have clinical and diagnostic potential. Simultaneous collection of breath VOCs and background environmental VOCs is important to ensure analyses eliminate exogenous compounds from clinical studies. We present a mobile sampling system to extract gaseous VOCs onto commercially available sorbent-packed thermal desorption tubes. The sampler can be connected to a number of commonly available disposable and reusable sampling bags, in the case of this study, a Tedlar bag containing a breath sample. Alternatively, the inlet can be left open to directly sample room or environmental air when obtaining a background VOC sample. The system contains a screen for the operator to input a desired sample volume. A needle valve allows the operator to control the sample flow rate, which operates with an accuracy of -1.52 ± 0.63% of the desired rate, and consistently generated that rate with 0.12 ± 0.06% error across repeated measures. A flow pump, flow sensor and microcontroller allow volumetric sampling, as opposed to timed sampling, with 0.06 ± 0.06% accuracy in the volume extracted. Four samplers were compared by sampling a standard chemical mixture, which resulted in 6.4 ± 4.7% error across all four replicate modular samplers to extract a given VOC. The samplers were deployed in a clinical setting to collect breath and background/environmental samples, including patients with active SARS-CoV-2 infections, and the device could easily move between rooms and can undergo required disinfection protocols to prevent transmission of pathogens on the case exterior. All components required for assembly are detailed and are made publicly available for non-commercial use, including the microcontroller software. We demonstrate the device collects volatile compounds, including use of chemical standards, and background and breath samples in real use conditions.


Subject(s)
Breath Tests , Environmental Monitoring , Volatile Organic Compounds , Breath Tests/methods , COVID-19/prevention & control , Environmental Monitoring/methods , Exhalation , Humans , SARS-CoV-2/isolation & purification , Volatile Organic Compounds/analysis
16.
J Bras Pneumol ; 48(2): e20210204, 2022.
Article in English, Portuguese | MEDLINE | ID: covidwho-1819118

ABSTRACT

OBJECTIVE: To evaluate small airway disease in COVID-19 patients using the prevalence of air trapping (AT) and correlating it with clinical outcomes. The relationship between CT-based opacities in small blood vessels and ventilation in patients with SARS-CoV-2 pneumonia was also assessed. METHODS: We retrospectively included 53 patients with positive RT-PCR results for SARS-CoV-2 between March and April of 2020. All subjects underwent HRCT scanning, including inspiratory and expiratory acquisitions. Subjects were divided into two groups based on visual identification of AT. Small blood vessel volumes were estimated by means of cross-sectional areas < 5 mm2 (BV5) derived from automated segmentation algorithms. Mixed-effect models were obtained to represent the BV5 as a function of CT-based lobar opacities and lobar ventilation. RESULTS: Of the 53 participants, AT was identified in 23 (43.4%). The presence of AT was associated with increased SpO2 at admission (OR = 1.25; 95% CI, 1.07-1.45; p = 0.004) and reduced D-dimer levels (OR = 0.99; 95% CI, 0.99-0.99; p = 0.039). Patients with AT were less likely to be hospitalized (OR = 0.27; 95% CI, 0.08-0.89; p = 0.032). There was a significant but weak inverse correlation between BV5 and CT-based lobar opacities (R2 = 0.19; p = 0.03), as well as a nonsignificant and weak direct correlation between BV5 and lobar ventilation (R2 = 0.08; p = 0.54). CONCLUSIONS: AT is a common finding in patients with COVID-19 that undergo expiratory CT scanning. The presence of AT may correlate with higher SpO2 at admission, lower D-dimer levels, and fewer hospitalizations when compared with absence of AT. Also, the volume of small pulmonary vessels may negatively correlate with CT opacities but not with lobar ventilation.


Subject(s)
COVID-19 , COVID-19/diagnostic imaging , Exhalation , Humans , Retrospective Studies , SARS-CoV-2 , Tomography, X-Ray Computed/methods
17.
Neurosciences (Riyadh) ; 27(2): 121, 2022 04.
Article in English | MEDLINE | ID: covidwho-1812607
18.
J Breath Res ; 16(3)2022 05 06.
Article in English | MEDLINE | ID: covidwho-1806207

ABSTRACT

COVID-19 detection currently relies on testing by reverse transcription polymerase chain reaction (RT-PCR) or antigen testing. However, SARS-CoV-2 is expected to cause significant metabolic changes in infected subjects due to both metabolic requirements for rapid viral replication and host immune responses. Analysis of volatile organic compounds (VOCs) from human breath can detect these metabolic changes and is therefore an alternative to RT-PCR or antigen assays. To identify VOC biomarkers of COVID-19, exhaled breath samples were collected from two sample groups into Tedlar bags: negative COVID-19 (n= 12) and positive COVID-19 symptomatic (n= 14). Next, VOCs were analyzed by headspace solid phase microextraction coupled to gas chromatography-mass spectrometry. Subjects with COVID-19 displayed a larger number of VOCs as well as overall higher total concentration of VOCs (p< 0.05). Univariate analyses of qualified endogenous VOCs showed approximately 18% of the VOCs were significantly differentially expressed between the two classes (p< 0.05), with most VOCs upregulated. Machine learning multivariate classification algorithms distinguished COVID-19 subjects with over 95% accuracy. The COVID-19 positive subjects could be differentiated into two distinct subgroups by machine learning classification, but these did not correspond with significant differences in number of symptoms. Next, samples were collected from subjects who had previously donated breath bags while experiencing COVID-19, and subsequently recovered (COVID Recovered subjects (n= 11)). Univariate and multivariate results showed >90% accuracy at identifying these new samples as Control (COVID-19 negative), thereby validating the classification model and demonstrating VOCs dysregulated by COVID are restored to baseline levels upon recovery.


Subject(s)
COVID-19 , Volatile Organic Compounds , Breath Tests/methods , Exhalation , Humans , SARS-CoV-2 , Volatile Organic Compounds/analysis
19.
PLoS One ; 16(11): e0257549, 2021.
Article in English | MEDLINE | ID: covidwho-1793615

ABSTRACT

Particulate generation occurs during exercise-induced exhalation, and research on this topic is scarce. Moreover, infection-control measures are inadequately implemented to avoid particulate generation. A laminar airflow ventilation system (LFVS) was developed to remove respiratory droplets released during treadmill exercise. This study aimed to investigate the relationship between the number of aerosols during training on a treadmill and exercise intensity and to elucidate the effect of the LFVS on aerosol removal during anaerobic exercise. In this single-center observational study, the exercise tests were performed on a treadmill at Running Science Lab in Japan on 20 healthy subjects (age: 29±12 years, men: 80%). The subjects had a broad spectrum of aerobic capacities and fitness levels, including athletes, and had no comorbidities. All of them received no medication. The exercise intensity was increased by 1-km/h increments until the heart rate reached 85% of the expected maximum rate and then maintained for 10 min. The first 10 subjects were analyzed to examine whether exercise increased the concentration of airborne particulates in the exhaled air. For the remaining 10 subjects, the LFVS was activated during constant-load exercise to compare the number of respiratory droplets before and after LFVS use. During exercise, a steady amount of particulates before the lactate threshold (LT) was followed by a significant and gradual increase in respiratory droplets after the LT, particularly during anaerobic exercise. Furthermore, respiratory droplets ≥0.3 µm significantly decreased after using LFVS (2120800±759700 vs. 560 ± 170, p<0.001). The amount of respiratory droplets significantly increased after LT. The LFVS enabled a significant decrease in respiratory droplets during anaerobic exercise in healthy subjects. This study's findings will aid in exercising safely during this pandemic.


Subject(s)
Air Conditioning/methods , COVID-19/prevention & control , Exercise/physiology , Particulate Matter/chemistry , Adult , Aerosols/chemistry , Air Filters , Anaerobic Threshold/physiology , COVID-19/metabolism , Exercise Test/methods , Exhalation/physiology , Female , Heart Rate/physiology , Humans , Japan , Lactic Acid/metabolism , Male , Oxygen Consumption/physiology , Respiration , Respiratory System/physiopathology , Running/physiology , SARS-CoV-2/pathogenicity , Ventilation/methods
20.
Pediatr Allergy Immunol ; 33 Suppl 27: 38-40, 2022 01.
Article in English | MEDLINE | ID: covidwho-1779268

ABSTRACT

Airborne particulate (PM) components from fossil fuel combustion can induce oxidative stress initiated by reactive oxygen species (ROS) that are strongly correlated with airway inflammation and asthma. A valid biomarker of airway inflammation is fractionated exhaled nitric oxide (FENO). The oxidative potential of PM2.5 can be evaluated with the dithiothreitol (DTT) dosage, which represents both ROS chemically produced and intracellular ROS of macrophages. This correlates with quality indicators of the internal environment and ventilation strategies such as dilution and removal of airborne contaminants.


Subject(s)
Air Pollutants , Air Pollution , Asthma , Air Pollutants/analysis , Air Pollutants/toxicity , Air Pollution/statistics & numerical data , Exhalation , Humans , Oxidative Stress , Particulate Matter/toxicity
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