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Short-range exposure to expired aerosols or droplet nuclei has been considered as the predominant route for SARS-CoV-2. The observed effect of mask wearing, and social distancing suggests the importance of expired jet in the spread of COVID-19. The well-known steady-state dilution model is no longer valid for the interrupted expiratory jet. We reanalysed the existing interrupted jet data and proposed a simple dilution model of expired jet using the two-stage jet model. The interrupted jet consists of two stages, i.e., the jet-like and puff-like stage. Results show dilution factor grows linearly with the distance at the jet-like stage but increases with the cubic of the increasing distance in the puff-like stage. Dilution factor at any distance for the puff-like stage decreases as the activity intensifies, which is still much larger than that estimated via the steady jet model. The findings can be further applied into the short-range airborne exposure assessment. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.
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SARS-CoV-2 infectious virions have been reported in exhaled breath, but their source remains elusive: breath sampling systems used to date do not separate breath aerosols by size, fail to prevent salivary/fomite contamination, or aerosol size evolution before sample capture. We hypothesised that sampling end-tidal, oral exhaled breath condensate (EBC), after separating large droplets by inertial impaction 4cm from the lips, would quantify viral loads in distal lung-derived fine aerosols (FA). We used a collector (PBM-HALE ) that captures mechanically aerosolised viruses to sample adult participants for <30 min under informed consent;cases symptomatic for <5 days (n=30) or >5 days (n=12), positive by nasopharyngeal swab RT-PCR (Ct>=13.1), were sampled in clinical triage 'red zones', or COVID-19 wards with no mechanical ventilation or open windows. Salivary alpha amylase activity (Salimetrics LLC), or SARS-CoV-2 viral load (VIASURE SARS-CoV-2 (ORF1ab and N gene)) after QIAsymhpony DSP midi extraction, was quantified in 0.2mL FA EBC fractions. No salivary alpha amylase activity was detected in healthy participant FA EBC (>1:1,750 dilution of paired saliva vs assay detection limit (n=300)). No SARS-CoV-2 RNA was detected in FA EBC (1.18mL +/- 0.32 total volume) among any COVID-19 cases (Aug 2020-Jan 2022) at limits of detection of 120 genomes/mL FA EBC or 4.72 genomes/min exhalation. No pre-extraction spike-in control reaction inhibition was observed. No ambient contamination of the alveolar FA EBC was detected with this sampling device. The alveolar fraction of orally exhaled tidal breath lacks detectable SARS-CoV-2 viral load.
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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has brought renewed attention to respiratory aerosol and droplet generation. While many studies have robustly quantified aerosol (<10 µm diameter) number and mass exhalation rates, fewer studies have explored larger droplet generation. This study quantifies respiratory droplets (>20 µm diameter) generated by a cohort of 76 adults and children using a water-sensitive paper droplet deposition approach. Unvoiced and voiced activities spanning different levels of loudness, different lengths of sustained phonation, and a specific manner of articulation in isolation were investigated. We find that oral articulation drives >20 µm droplet generation, with breathing generating virtually no droplets and speaking and singing generating on the order of 250 droplets min−1. Lip trilling, which requires extensive oral articulation, generated the most droplets, whereas shouting "Hey,” which requires minimal oral articulation, generated relatively few droplets. Droplet size distributions were all broadly consistent, and no significant differences between the children and adult cohorts were identified. By comparing the aerosol and droplet emissions for the same participants, the full size distribution of respiratory aerosol (0.5–1000 µm) is reported. Although <10 µm aerosol dominates the number concentration, >20 µm droplets dominate the mass concentration. Accurate quantification of aerosol concentrations in the 10–70 μm size range remains very challenging;more robust aerosol analysis approaches are needed to characterize this size range.
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The breathing rate monitoring is an important measure in medical applications and daily physical activities. The contact sensors have shown their effectiveness for breathing monitoring and have been mostly used as a standard reference, but with some disadvantages for example in burns patients with vulnerable skins. Contactless monitoring systems are then gaining attention for respiratory frequency detection. We propose a new non-contact technique to estimate the breathing rate based on the motion video magnification method by means of the Hermite transform and an Artificial Hydrocarbon Network (AHN). The chest movements are tracked by the system without the use of an ROI in the image video. The machine learning system classifies the frames as inhalation or exhalation using a Bayesian-optimized AHN. The method was compared using an optimized Convolutional Neural Network (CNN). This proposal has been tested on a Data-Set containing ten healthy subjects in four positions. The percentage error and the Bland–Altman analysis is used to compare the performance of the strategies estimating the breathing rate. Besides, the Bland–Altman analysis is used to search for the agreement of the estimation to the reference.The percentage error for the AHN method is 2.19±2.1 with and agreement with respect of the reference of ≈99%.
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Activities such as singing or playing a wind instrument release respiratory particles into the air that may contain pathogens and thus pose a risk for infection transmission. Here we report measurements of the size distribution, number, and volume concentration of exhaled particles from 31 healthy musicians playing 20 types of wind instruments using aerosol size spectrometry complemented with in-line holography in a strictly controlled cleanroom environment. We find that playing wind instruments carries a lower risk of airborne disease transmission than speaking or singing. We attribute this to the fact that the resonators of wind instruments act as filters for particles >10 µm in diameter, which were found in high abundance right after a brass mouthpiece but very rarely at the instrument bell end. We have also measured the size-dependent filtering properties of different types of filters that can be used as instrument masks. Based on these measurements, we calculated the risk of airborne transmission of SARS-CoV-2 in different near- and far-field scenarios with and without masking and/or distancing. We conclude that in all cases where there is a possibility that the musician is infectious, the only safe measure to prevent airborne transmission of the disease is the use of well-fitting and well-filtering masks for the instrument and the susceptible person. © 2022 The Author(s)
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Introduction: There are no FDA-approved medications for the >20 million chronic rhinosinusitis patients without nasal polyps. The Exhalation Delivery System with Fluticasone (EDS-FLU) is an intranasal steroid in a device that delivers drug to regions above the inferior turbinate and behind the nasal valve. Method(s): In this phase 3, 24-week, randomized, controlled trial evaluating EDS-FLU versus EDS-placebo twice daily in chronic sinusitis without polyps, co-primary endpoints were combined symptom score (CSS;week 4) and average of percentages of CT-opacified volume across ethmoid/maxillary sinuses (APOV;week 24). Other outcomes included Quality-of-Life (SNOT-22, SF-36), Sleep (PSQI), and Patient-reported Global Impression of Change (PGIC). Result(s): Baseline scores suggest moderate-severe disease: mean CSS=6.0;APOV=62.0%. Both EDS-FLU doses [186microg (n=74) and 372microg (n=74)] significantly reduced both symptoms and sinus opacification versus EDS-placebo (n=75): CSS least-square (LS) mean change, EDS-placebo, -0.81;EDS-FLU 186microg, -1.54 (p<.05);EDS-FLU 372microg, -1.74, (p<.001);APOV LS mean change +1.19, -7.00 (p<.001), -5.14 (p<.01), respectively. EDS-FLU (n=145) vs EDS-placebo (n=75) also significantly improved secondary measures at Week 24 including SNOT-22 (LS mean -17.5 vs -8.7, p=.001);SF-36v2 (LS Mean PCS 4.9 vs 1.8, p=.002);PSQI Global score (LS mean -1.54 vs -.33;p<.001);and PGIC (60% vs 25% much/very much improved;p<.001). Adverse events (>=3% of patients and >EDS-placebo) were COVID-19, epistaxis, headache, and depression. Conclusion(s): EDS-FLU is the first and only drug to show improvement in a phase 3 trial in both symptoms and sinus opacification in chronic rhinosinusitis without nasal polyps. Copyright © 2022
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Background. Data suggest chronic rhinosinusitis (CRS) may be the top reason for adult outpatient antibiotic use;of =10 million office visits per year for CRS, =70% result in antibiotic use. Acute exacerbations of CRS (AECRS) are common, possibly due to persistently impaired mucociliary clearance, and drive use of antibiotics. No drugs have been shown effective for reducing AECRS. ReOpen1 and 2 are randomized controlled trials that evaluated prevention of AECRS with the exhalation delivery system with fluticasone (EDS-FLU;XHANCE), a novel device delivering topical steroid into chronically inflamed sinonasal regions not typically accessible with standard nasal sprays (eg, past the nasal valve and above the inferior turbinate). Methods. CRS patients were randomized to EDS-FLU one or two sprays per nostril or placebo twice daily (BID) for 24 weeks. Frequency of AECRS, defined as worsening of at least 1 cardinal symptom of CRS (nasal congestion/obstruction, rhinorrhea, facial pain/pressure, hyposmia/anosmia) for >= 3 days requiring escalation of medical care (eg, doctor visit, antibiotic or steroid prescription), was analyzed using pooled data from both trials. Results. Among 555 patients enrolled, 39.4% were using standard nasal steroids at study entry and 38.8% reported prior sinus surgery. There were 76 AECRS over 24 weeks, almost all (71) resulting in antibiotic use. Patients receiving EDS-FLU had a large reduction in AECRS versus placebo (incidence rate ratio [IRR]=0.39, P=0.001, vs placebo). Reduction was greater at the higher dose (2 sprays/nostril BID) than the lower dose (1 spray/nostril BID): IRR=0.34, P=0.002;IRR=0.44, P=0.012, respectively. 9.9% of low-dose patients and 7.8% of high-dose patients had >= 1 AECRS (20 and 15 events, respectively) vs 15.7% receiving placebo (41 events;P=0.012 and P=0.002 vs placebo, respectively). Treatment was well tolerated: adverse events in >= 3% of patients and more common in one active group than placebo were epistaxis, COVID-19, headache, and nasopharyngitis. Conclusion. EDS-FLU is the first and only medication shown in randomized controlled trials to significantly reduce acute exacerbations of CRS, offering potential to improve antibiotic stewardship by substantially reducing one of the most common drivers of outpatient antibiotic use. (Figure Presented).
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Computational fluid dynamics models have been developed to predict airborne exposure to the SARS-CoV-2 virus from a coughing person in a mechanically ventilated room. The models were run with three typical indoor air temperatures and relative humidities (RH). Quantile regression was used to indicate whether these have a statistically significant effect on the airborne exposure. Results suggest that evaporation is an important effect. Evaporation leads to respiratory particles, particularly those with initial diameters between 20 and 100 µm, remaining airborne for longer, traveling extended distances and carrying more viruses than expected from their final diameter. In a mechanically ventilated room, with all of the associated complex air movement and turbulence, increasing the RH may result in reduced airborne exposure. However, this effect may be so small that other factors, such as a small change in proximity to the infected person, could rapidly counter the effect. The effect of temperature on the exposure was more complex, with both positive and negative correlations. Therefore, within the range of conditions studied here, there is no clear guidance on how the temperature should be controlled to reduce exposure. The results highlight the importance of ventilation, face coverings and maintaining social distancing for reducing exposure.
Sujets)
Pollution de l'air intérieur , COVID-19 , Humains , Humidité , Température , SARS-CoV-2 , Pollution de l'air intérieur/analyse , Ventilation artificielleRésumé
Background: Computational fluid dynamics (CFD) simulations, in-vitro setups, and experimental ex-vivo approaches have been applied to numerous alveolar geometries over the past years. They aimed to study and examine airflow patterns, particle transport, particle propagation depth, particle residence times, and particle-alveolar wall deposition fractions. These studies are imperative to both pharmaceutical and toxicological studies, especially nowadays with the escalation of the menacing COVID-19 virus. However, most of these studies ignored the surfactant layer that covers the alveoli and the effect of the air-surfactant surface tension on flow dynamics and air-alveolar surface mechanics. Methods: The present study employs a realistic human breathing profile of 4.75s for one complete breathing cycle to emphasize the importance of the surfactant layer by numerically comparing airflow phenomena between a surfactant-enriched and surfactant-deficient model. The acinar model exhibits physiologically accurate alveolar and duct dimensions extending from lung generations 18 to 23. Airflow patterns in the surfactant-enriched model support previous findings that the recirculation of the flow is affected by its propagation depth. Proximal lung generations experience dominant recirculating flow while farther generations in the distal alveolar region exhibit dominant radial flows. In the surfactant-enriched model, surface tension values alternate during inhalation and exhalation, with values increasing to 25 mN/m at the inhalation and decreasing to 1 mN/m at the end of the exhalation. In the surfactant-deficient model, only water coats the alveolar walls with a high surface tension value of 70 mN/m. Results: Results showed that surfactant deficiency in the alveoli adversely alters airflow behavior and generates unsteady chaotic breathing through the production of vorticities, accompanied by higher vorticity magnitudes (100% increase at the end of exhalation) and higher velocity magnitudes (8.69% increase during inhalation and 11.9% increase during exhalation). In addition, high air-water surface tension in the surfactant-deficient case was found to induce higher shear stress values (by around a factor of 10) on the alveolar walls than that of the surfactant-enriched case. Conclusion: Overall, it was concluded that the presence of the surfactant improves respiratory mechanics and allows for smooth breathing and normal respiration.
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SESSION TITLE: Late Breaking Investigations From Pulmonary and Critical Care SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/18/2022 01:30 pm - 02:30 pm PURPOSE: Although spirometry is the standard lung functional test, it requires the patient to perform a series of maneuvers correctly, which is difficult for elderly, children, and patients with severe lung impairments. Furthermore, spirometry lacks regional assessment for detecting and monitoring subtle changes in lung diseases, e.g., chronic obstructive pulmonary disease (COPD) and potentially COVID-19. We aim to establish a home-based imaging system, portable electrical impedance tomography (EIT), that can detect lung function deterioration and monitor its recovery through a close-to-effortless breathing paradigm. METHODS: We developed a palm-sized EIT system and a novel guided breathing paradigm that consists of a periodic inhalation and exhalation at 12 breaths per minute. We validated them on healthy subjects (n=23) performing different breathing efforts (deep vs shallow), then on patients with ILD (n=2), COPD (n=8), asthma (n=4) and bronchiectasis (n=4) against healthy (n=8) cross-sectionally, and last monitored a COVID-19 discharged subject with two age- and gender-matched healthy controls longitudinally. We further applied machine learning to distinguish between healthy and patients, and calculated its sensitivity and specificity. RESULTS: We detected higher amplitude during deep breathing compared to shallow (p < 0.001) in healthy subjects, with right lung having more activated voxels and higher total amplitude than the left lung (p < 0.001), likely due to the position of the heart. Cross-sectionally, we observed lower amplitude in patients compared to healthy (p < 0.01), while coefficient of variation (CV) of the amplitude in the lungs is higher in patients (p < 0.05). Note that CV is a parameter reflecting inhomogeneity which is indicative of lung function deterioration. Longitudinally, the COVID-19 discharged subject had higher CV in the left lung (p < 0.001) which decreased across time (p < 0.01), suggesting a functional deterioration at the beginning followed by a recovery. Regional analysis further pin-pointed the potential deterioration and recovery was in the anterior left lung. Separately, despite the small sample size, the sensitivity and specificity for detecting patients using a machine learning classifier were 76% and 62%, respectively, and will likely increase with a larger sample. CONCLUSIONS: Home-based portable EIT with close-to-effortless guided breathing paradigm can map global and regional lung function deterioration and recovery cross-sectionally and longitudinally. More importantly, it can potentially be deployed as a screening tool for various lung diseases through the application of machine learning. CLINICAL IMPLICATIONS: Portable EIT with guided breathing paradigm enables lung function diagnostic screening and treatment monitoring at home, advancing telemedicine and lowering hospital burden. DISCLOSURES: no disclosure on file for Peng Cao;Owner/Founder relationship with Gense Technologies Ltd Please note: Since 2017 Added 06/06/2022 by Russell Chan, value=Ownership interest No relevant relationships by Wang Chun Kwok No relevant relationships by Wei-Ning Lee No relevant relationships by Terence Tam Employee relationship with Gense Technologies Please note: Setpember 2021 - Now Added 06/07/2022 by Adrien Touboul, value=Salary contractor relationship with Gense Technologies Ltd Please note: since Apr 2021 Added 06/06/2022 by Eddie Wong, value=Consulting fee Employee relationship with Gense Technologies Please note: since 2020 Added 06/06/2022 by Fedi Zouari, value=Royalty
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SESSION TITLE: Respiratory Care: Oxygen, Rehabilitation, and Inhalers SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/18/2022 01:30 pm - 02:30 pm PURPOSE: The SARS-CoV-2 pandemic has highlighted the need to avoid environmental contamination with aerosols. To aid in this, the addition of a filter kit is intended to capture any exhaled aerosol. To determine the aerosol amounts emitted to the environment during nebulizer therapy several nebulizers were evaluated to test the efficiency of the nebulizer filter system. METHODS: The MaxiNeb® Duo, Circulaire® II and AeroEclipse® II BAN™ Nebulizer were operated at 50PSIG with their optional filter kits (n=5). Each device was evaluated with 2.5mg/3.0mL fill of albuterol and connected to a simulator mimicking adult tidal breathing. In addition to inspiratory and expiratory filters, the nebulizer was placed under an extraction system to capture any aerosol emitted through leakages or exhalation. Albuterol assay was undertaken by HPLC-UV spectrophotometry. RESULTS: The mass of albuterol captured from the extraction system with the MaxiNeb® Duo, Circulaire® II and AeroEclipse® II BAN™ Nebulizer was found to be 0.5±0.2, 1.5±0.6 and 0.0±0.0% of the initial dose respectively. CONCLUSIONS: The BAN™ Nebulizer without filter kit has previously reported environmental losses of just under 3%ꝉ so it is in keeping that the addition of the filter kit eliminated all losses for this device. The other two nebulizers emitted small amounts of aerosol even when a filter kit was used. CLINICAL IMPLICATIONS: If the laboratory results for the nebulizer / filter systems which did not eliminate all environmental emissions were replicated in a clinical setting, there would likely need to be an assessment performed into the potential risk to staff and patients. ꝉ Efficiency of a Nebulizer Filter Kit to Prevent Environmental Contamination During Nebulizer Therapy – presented at European Respiratory Society Meeting 2021 DISCLOSURES: Employee relationship with Trudell Medical International Please note: 27 years by Mark Nagel, value=Salary Employee relationship with Trudell Medical International Please note: >$100000 by Jason Suggett, value=Salary
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This present work provides an easily disposable paper-based interdigitated sensor embedded inside the mask for the detection of respiration rate continuously without direct contact with the human body. In present COVID scenario, everyone needs to wear mask for preventing the unwanted spreading of the said virus. But in tropical countries like India, People always complain about a suffocating situation while wearing mask. In order to address this, we have designed a non-invasive paper sensor that can be placed inside the mask (beneath nostril) for measuring breathing rate regularly to find out a cost-effective device capable of monitoring breathing rate. In general, we prefer use and throw type mask, thus the proposed paper-based sensor gives a cost-effective solution compared to the Current appliances of breathing sensing as most of them are burdensome, bulky, inconvenient as well as exorbitant than a paper-based respiration sensor. Essentially, these current approaches undergo through a practical limitation of frequency and time span i.e. static measurement. It is known that the humidity level of a paper changes according to the moisture content. Thus, it can easily detect the inhalation and exhalation through this changing. Moreover, variation of moisture level that happens due to breathing cycle changes the ionic conductivity of the sensor. The interdigitated design is the most suited for achieving higher sensitivity and easy to fabricate. First, we have designed it in Finite Element Method (FEM) based platf orm and finally this design is implemented with graphite-based electrodes on cellulose paper. Microcontroller based electronic circuitry is used in order to monitor and record the real-time respiration rate. It has been observed that the breathing rate as well as pattern gives a significant variation along with physical conditions and obstructive pulmonary diseases.
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Background: The study wanted to see if diaphragmatic sonography was able to assess physical changes after a respiratory rehabilitation program in COVID-19 patients. Methods: Fifty patients (10 women and 40 males aged between 20 and 86 years) were trained by the physiotherapist to use the pep bottle and the active exercise from the beginning in the COVID-19 unit and then in Rehabilitation unit. The physiotherapist evaluated the diaphragm excursion with a sonography machine set in abdominal protocol way with a convex probe. The sonography allows to evaluate, before and upon discharge, the maximal diaphragmatic excursion and the maximal expiratory time during forced expiration as an alternative test to six minute walking test when the patients were unable to walk or could not leave the room due to infections. Results: Despite the difficulty of performing the examination due to physical conditions of work and clinical criticity of the patients in COVID unit we could observe that: - 44 patients (n.11 were with tracheotomy) improved the maximal diaphragmatic excursion while 4 patients have gotten worse because they were uncooperative and 2 for physical problems. - 38 patients improved the maximal expiratory time while 4 were uncooperative and 8 patients have had a cough which interrupted the exhalation. Conclusions: The diaphragm sonography can be a simple and safe method to study, at the bed side patient, the modification of the muscle excursion and evaluate the progress of therapy during rehabilitation treatment.
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Objective: All respiratory care represents some risk of becoming an aerosol-generating procedure (AGP) during COVID-19 patient management. Personal protective equipment (PPE) and environmental control/engineering is advised. High velocity nasal insufflation (HVNI) and high flow nasal cannula (HFNC) deliver high flow oxygen (HFO) therapy, established as a competent means of supporting oxygenation for acute respiratory distress patients, including that precipitated by COVID-19. Although unlikely to present a disproportionate particle dispersal risk, AGP from HFO continues to be a concern. Previously, we published a preliminary model. Here, we present a subsequent highresolution simulation (higher complexity/reliability) to provide a more accurate and precise particle characterization on the effect of surgical masks on patients during HVNI, low-flow oxygen therapy (LFO2), and tidal breathing. Methods: This in silico modeling study of HVNI, LFO2, and tidal breathing presents ANSYS fluent computational fluid dynamics simulations that evaluate the effect of Type I surgical mask use over patient face on particle/droplet behavior. Results: This in silico modeling simulation study of HVNI (40 L min-1) with a simulated surgical mask suggests 88.8% capture of exhaled particulate mass in the mask, compared to 77.4% in LFO2 (6 L min-1) capture, with particle distribution escaping to the room (> 1 m from face) lower for HVNI+Mask versus LFO2+Mask (8.23% vs 17.2%). The overwhelming proportion of particulate escape was associated with mask-fit designed model gaps. Particle dispersion was associated with lower velocity. Conclusions: These simulations suggest employing a surgical mask over the HVNI interface may be useful in reduction of particulate mass distribution associated with AGPs.
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When searching for ‘total inward leakage’ on Google, the first hit refers to a statement by the National Institute of Occupational Safety and Health [3]: “Total inward leakage (TIL) is an estimate of the performance of a respirator, which is measured as the leakage of contaminants through the filter media and through the face-seal interface and exhalation valve of respiratory protective devices under laboratory conditions. There is a lack of consensus on the most appropriate test method to measure TIL”. [...]it is not useful to discuss this with respect to its application in EN149:2001 [2]. For other tasks, good quality surgical masks provide sufficient protection. Since our paper was published, two additional systematic reviews have analyzed the current collection of studies, including the more recent studies.
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Purpose of Study Today's mechanical ventilators require adjustments of respiratory rate, inspiratory time, expiratory time and tidal volume to maximize O2 delivery and CO2 removal. Pranayam was first recorded about 7000 years ago, and shows similar results to ventilation. Involving conscious inhalation, exhalation and holding of breath, Pranayam is held prominent in the Yoga Sutra (historical authoritative text on Yoga). Pranayam includes three primary principles: Puraka, Rechaka and Kumbhaka, and the techniques of Kapalbhati and Bhastrika. Slow breathing stimulates the vagus nerve and parasympathetic nervous system, easing inhibition of the sympathetic 'fight or flight' response. Pranayam also enhances nitric oxide (NO) production. Recent studies using NO for COVID-19 treatment via inhaler show promising results in shortening the course, symptom severity and resulting damage. When practiced regularly, Pranayam enhances cellular gas exchange, increasing O2 levels and enhancing detox. This study draws parallels between Pranayam and modern ventilation in management of obstetric and pediatric conditions. Methods Used Literature search of ancient Indian texts (Upanishads and Yoga Vasishta, Bhagavad Gita, Patanjali Yoga Sutras) and recent publications on modern ventilation and its clinical applications. Summary of Results Several therapies in allopathic medicine show similar principles to Pranayam in prevention and management of ailments. Maximizing O2 delivery and CO2 removal is accomplished through low tidal volumes and high rates in conventional mechanical ventilators, and extremely low tidal volumes in high frequency oscillators and jet ventilators. These can be compared to high frequency breaths in Pranayam with air exchange improvement and positive alteration of acid/base balance, aiming to avoid lung injury from high distending pressures, especially for infants. Ventilatory strategies such as high pressure and low rate also have their equivalent in Pranayam. Conclusions Breath manipulations in modern medicine and the ancient technique of Pranayam have a positive impact on preventing many human ailments, especially in the fields of perinatology and pediatrics. Breathing exercises can prevent anxiety episodes, mountain sickness and asthma exacerbations. They are also taught to expectant mothers to reduce labor pain during contractions. Human trials show increased pulmonary function and endogenous NO by regular practice of these techniques, which have been used as an adjuvant in COVID-19 patient care. These parallels between Pranayam and ventilatory techniques show a synthesis of ancient and modern therapy. (Figure Presented).
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Violent respiratory events play critical roles in the transmission of respiratory diseases, such as coughing and sneezing, between infectious and susceptible individuals. In this work, large-scale multiphase flow large-eddy simulations have been performed to simulate the coughing jet from a human's mouth carrying pathogenic or virus-laden droplets by using a weakly compressible smoothed particle hydrodynamics method. We explicitly model the cough jet ejected from a human mouth in the form of a mixture of two-phase fluids based on the cough velocity profile of the exhalation flow obtained from experimental data and the statistics of the droplets’ sizes. The coupling and interaction between the two expiratory phases and ambient surrounding air are examined based on the interaction between the gas particles and droplet particles. First, the results reveal that the turbulence of the cough jet determines the dispersion of the virus-laden droplets, i.e. whether they fly up evolving into aerosols or fall down to the ground. Second, the droplet particles have significant effects on the evolution of the cough jet turbulence;for example, they increase the complexity and butterfly effect introduced by the turbulence disturbance. Our results show that the prediction of the spreading distance of droplet particles often goes beyond the social distancing rules recommended by the World Health Organization, which reminds us of the risks of exposure if we do not take any protecting protocol.
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The recent Covid-19 pandemic has drawn attention to the amount of fugitive aerosol that is emitted by nebulizers. The novel I-neb Advance Adaptive Aerosol Delivery (AAD) System incorporates an improved AAD algorithm intended to reduce treatment times compared with earlier AAD devices. We conducted an in vitro test to determine the amount of fugitive aerosol that is emitted from the I-neb Advance (AAD) System. Three production equivalent investigational I-neb Advance nebulizers fitted with nonmetering chambers were filled with 1.7mL of 2mg/mL salbutamol solution. The delivered dose was collected on a filter during operation into a simulated breathing pattern (Tv=500mL, I:E=1:1, f 15 bpm). A second filter was fixed 1 cm away from the exhalation port of the nebulizer with an extraction flow of 60 L/min. Each nebulizer was run in triplicate. Salbutamol on filters was quantitated by high performance liquid chromatography. The delivered doses had low co-efficients of variation, intra-nebulizer=0.83 to 3% and inter-nebulizer=0.77%. The fugitive aerosol was lower than the limit of quantification of the assay (0.18% of fill) in 2/3 of the tests. Measurable exhaled doses were all below 0.3% of the fill volume. The improved AAD algorithm used in the I-neb Advance (AAD) System delivered precise, reproducible doses with minimal fugitive aerosol emissions into a simulated breathing pattern. The minimization of fugitive aerosol emissions demonstrated by AAD nebulizers likely has an added relevance to aerosol treatment following the emergence of the Covid-19 pandemic. Key Message: The novel I-neb Advance (AAD) System was shown to deliver reproducible doses of drug with minimal (<0.3% of the nominal dose) fugitive aerosol emissions. This observation could be important in clinical situations where there is a need to minimise escaping aerosol from nebuliser devices during use.
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In closed buses, the spread of droplets with viruses/bacteria may cause the spread of respiratory infectious diseases. Discrete phase modeling is used to simulate the diffusion characteristics and concentration distribution of droplets at different temperatures and different exhalation positions by ANSYS FLUENT software. The integral concentration of droplets at different locations can be quantified, which leads to identification of low-risk areas and high-risk areas in the bus. Results show that a higher outdoor temperature leads to lower droplets’ diffusion speed and longer time until the droplets reach the driver. In addition, based on the integral concentration of droplets at the seats, regardless of whether a passenger exhales droplets in the front row of the bus, the position of the rear door or the last row of the bus, the seats in the last row of the bus away from the door belong to the low-risk area. In contrast, the seats near the door and the middle seat in the bus are higher risk areas. Consequently, this study proposed sitting on a seat in the low-risk area as a means to reduce the risk of passengers. Moreover, safety protection facilities around the driver should be modified to improve the isolation of the upper area of the driver’s location, so as to effectively prevent the droplet diffusion towards the driver, thereby effectively reducing the driver’s risk of infection.
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Background: During mechanical ventilation of a patient requiring ventilatory support, bystanders could potentially be exposed to aerosolised drug. Methods: Fugitive drug aerosol emissions during simulated adult mechanical ventilation was assessed on a dual limb circuit. Tidal volume was set at 270 mL and 820 mL. The use of a protective filter on the exhalation port of the mechanical ventilator was assessed. Results: Higher fugitive aerosol mass concentrations in the local environment were associated with larger tidal volume (0.077 (0.073, 0.091) mg m–3 at Vt = 820 mL vs. 0.062 (0.056, 0.065) mg m–3 at Vt = 270 mL) when no protective filter was used. The range of mass median aerodynamic diameters recorded was from 0.93 to 2.96 µm. When a filter was placed on the exhalation port of the mechanical ventilator, no fugitive emissions were recorded. Conclusion: This study confirms that an appropriate filtration protocol mitigates the risk of fugitive emissions being released when patients undergo aerosol therapy during mechanical ventilation. A larger tidal volume resulted in higher fugitive aerosol mass.