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Seyedzadeh H, Craig J, Khosronejad A. On the efficacy of facial masks to suppress the spreading of pathogen-carrying saliva particles during human respiratory events: Insights gained via high-fidelity numerical modeling. MEDICAL RESEARCH ARCHIVES 2024; 12:5441. [PMID: 38911991 PMCID: PMC11192503 DOI: 10.18103/mra.v12i5.5441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Respiratory fluid dynamics is integral to comprehending the transmission of infectious diseases and the effectiveness of interventions such as face masks and social distancing. In this research, we present our recent studies that investigate respiratory particle transport via high-fidelity large eddy simulation coupled with the Lagrangian particle tracking method. Based on our numerical simulation results for human respiratory events with and without face masks, we demonstrate that facial masks could significantly suppress particle spreading. The studied respiratory events include coughing and normal breathing through mouth and nose. Using the Lagrangian particle tracking simulation results, we elucidated the transport pathways of saliva particles during inhalation and exhalation of breathing cycles, contributing to our understanding of respiratory physiology and potential disease transmission routes. Our findings underscore the importance of respiratory fluid dynamics research in informing public health strategies to reduce the spread of respiratory infections. Combining advanced mathematical modeling techniques with experimental data will help future research on airborne disease transmission dynamics and the effectiveness of preventive measures such as face masks.
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Affiliation(s)
- Hossein Seyedzadeh
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Jonathan Craig
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Ali Khosronejad
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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Sabz M, Noga ML, Finlay WH, Rouhani H, Martin AR. High-Flow and Low-Flow Oxygen Delivery by Nasal Cannula Evaluated in Infant and Adult Airway Replicas. Respir Care 2024; 69:438-448. [PMID: 38443141 PMCID: PMC11108111 DOI: 10.4187/respcare.11438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
BACKGROUND The nasal cannula is widely regarded as a safe and effective means of administering low- and high-flow oxygen to patients irrespective of their age. However, variability in delivered oxygen concentration (FDO2 FDO2 ) via nasal cannula has the potential to pose health risks. The present study aimed to evaluate predictive equations for FDO2 over a large parameter space, including variation in breathing, oxygen flow, and upper-airway geometry representative of both young children and adults. METHODS Realistic nasal airway geometries were previously collected from medical scans of adults, infants, and neonates. Nasal airway replicas based on these geometries were used to measure the FDO2 for low-flow oxygen delivery during simulated spontaneous breathing. The present study extends previously published data sets to include higher oxygen flows. The extended data sets included nasal cannula oxygen flows that ranged from 6 to 65 L/min for the adult replicas, and from 0.5 to 6 L/min for the infant replicas. For both age groups, FDO2 was measured over a range of breathing frequencies, inspiratory to expiratory time ratios, and tidal volumes. Measured FDO2 values were compared with values predicted by using a previously derived flow-weighted equation. RESULTS For both age groups, FDO2 was observed to increase nonlinearly with the ratio between oxygen flow supplied to the nasal cannula and the average inhalation flow. The previously derived flow-weighted equation over-predicted FDO2 at higher oxygen flows. A new empirical equation, therefore, was proposed to predict FDO2 for either age group as a function of nasal cannula flow, tidal volume, and inspiratory time. Predicted FDO2 values matched measured values, with average relative errors of 2.4% for infants and 4.3% for adults. CONCLUSIONS A new predictive equation for FDO2 was obtained that accurately matched measured data in both adult and infant airway replicas for low- and high-flow regimens.
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Affiliation(s)
- Mozhgan Sabz
- Ms Sabz, Drs Finlay, Rouhani, and Martin are affiliated with the Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada. Dr Noga is affiliated with the Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Michelle L Noga
- Ms Sabz, Drs Finlay, Rouhani, and Martin are affiliated with the Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada. Dr Noga is affiliated with the Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Warren H Finlay
- Ms Sabz, Drs Finlay, Rouhani, and Martin are affiliated with the Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada. Dr Noga is affiliated with the Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Hossein Rouhani
- Ms Sabz, Drs Finlay, Rouhani, and Martin are affiliated with the Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada. Dr Noga is affiliated with the Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew R Martin
- Ms Sabz, Drs Finlay, Rouhani, and Martin are affiliated with the Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada. Dr Noga is affiliated with the Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada.
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Leclerc L, Prévôt N, Hodin S, Delavenne X, Mentzel H, Schuschnig U, Pourchez J. Acoustic Aerosol Delivery: Assessing of Various Nasal Delivery Techniques and Medical Devices on Intrasinus Drug Deposition. Pharmaceuticals (Basel) 2023; 16:135. [PMID: 37259287 PMCID: PMC9962259 DOI: 10.3390/ph16020135] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 07/31/2023] Open
Abstract
This study aims to evaluate the impact of the nasal delivery technique and nebulizing technologies (using different frequencies of oscillating airflow) for acoustic aerosol targeting of maxillary sinuses. Sodium fluoride (chemical used as a marker), tobramycin (drug used as a marker) and 99mTc-DTPA (radiolabel aerosol) were used to assess the intrasinus aerosol deposition on a nasal cast. Two commercial medical devices (PARI SINUS nebulizer and NL11SN ATOMISOR nebulizer) and various nasal delivery techniques (one or two nostrils connected to the aerosol inlet, the patient with the soft palate closed or open during the acoustic administration of the drug, the presence or not of flow resistance in the nostril opposite to the one allowing the aerosol to be administered) were evaluated. The closed soft palate condition showed a significant increase in drug deposition even though no significant difference in the rest of the nasal fossae was noticed. Our results clearly demonstrated a higher intrasinus aerosol deposition (by a factor 2-3; respectively 0.03 ± 0.007% vs. 0.003 ± 0.0002% in the right maxillary sinus and 0.027 ± 0.006% vs. 0.013 ± 0.004% in the left maxillary sinus) using the acoustic airflow generated by the PARI SINUS compared to the NL11SN ATOMISOR. The results clearly demonstrated that the optimal conditions for aerosol deposition in the maxillary sinuses were obtained with a closed soft palate. Thus, the choice of the nebulizing technology (and mainly the frequency of the pulsating aerosol generated) and also the recommendation of the best nasal delivery technique are key factors to improve intrasinus aerosol deposition.
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Affiliation(s)
- Lara Leclerc
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, Sainbiose U1059, Centre CIS, F-42023 Saint-Etienne, France
| | - Nathalie Prévôt
- Université Jean Monnet Saint-Étienne, Mines Saint-Etienne, INSERM, Sainbiose U1059, F-42023 Saint-Etienne, France
- Nuclear Medicine Unit, CHU Saint-Etienne, F-42055 Saint-Etienne, France
| | - Sophie Hodin
- Université Jean Monnet Saint-Étienne, Mines Saint-Etienne, INSERM, Sainbiose U1059, F-42023 Saint-Etienne, France
| | - Xavier Delavenne
- Université Jean Monnet Saint-Étienne, Mines Saint-Etienne, INSERM, Sainbiose U1059, F-42023 Saint-Etienne, France
| | | | | | - Jérémie Pourchez
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, Sainbiose U1059, Centre CIS, F-42023 Saint-Etienne, France
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Sabz M, Tavernini S, Pillay K, Christianson C, Noga M, Finlay WH, Rouhani H, Martin AR. Variability in low-flow oxygen delivery by nasal cannula evaluated in neonatal and infant airway replicas. Respir Res 2022; 23:333. [PMID: 36482438 PMCID: PMC9730608 DOI: 10.1186/s12931-022-02260-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The nasal cannula is considered a trusted and effective means of administering low-flow oxygen and is widely used for neonates and infants requiring oxygen therapy, despite an understanding that oxygen concentrations delivered to patients are variable. METHODS In the present study, realistic nasal airway replicas derived from medical scans of children less than 3 months old were used to measure the fraction of oxygen inhaled (FiO2) through nasal cannulas during low-flow oxygen delivery. Parameters influencing variability in FiO2 were evaluated, as was the hypothesis that measured FiO2 values could be predicted using a simple, flow-weighted calculation that assumes ideal mixing of oxygen with entrained room air. Tidal breathing through neonatal and infant nasal airway replicas was controlled using a lung simulator. Parameters for nasal cannula oxygen flow rate, nasal airway geometry, tidal volume, respiratory rate, inhalation/exhalation, or I:E ratio (ti/te), breath waveform, and cannula prong insertion position were varied to determine their effect on measured FiO2. In total, FiO2 was measured for 384 different parameter combinations, with each combination repeated in triplicate. Analysis of variance (ANOVA) was used to assess the influence of parameters on measured FiO2. RESULTS Measured FiO2 was not appreciably affected by the breath waveform shape, the replica geometry, or the cannula position but was significantly influenced by the tidal volume, the inhalation time, and the nasal cannula flow rate. CONCLUSIONS The flow-weighted calculation overpredicted FiO2 for measured values above 60%, but an empirical correction to the calculation provided good agreement with measured FiO2 across the full range of experimental data.
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Affiliation(s)
- Mozhgan Sabz
- grid.17089.370000 0001 2190 316XDepartment of Mechanical Engineering, University of Alberta, Edmonton, AB Canada
| | - Scott Tavernini
- grid.17089.370000 0001 2190 316XDepartment of Mechanical Engineering, University of Alberta, Edmonton, AB Canada
| | - Kineshta Pillay
- grid.17089.370000 0001 2190 316XDepartment of Mechanical Engineering, University of Alberta, Edmonton, AB Canada
| | - Cole Christianson
- grid.17089.370000 0001 2190 316XDepartment of Mechanical Engineering, University of Alberta, Edmonton, AB Canada
| | - Michelle Noga
- grid.17089.370000 0001 2190 316XDepartment of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, AB Canada
| | - Warren H. Finlay
- grid.17089.370000 0001 2190 316XDepartment of Mechanical Engineering, University of Alberta, Edmonton, AB Canada
| | - Hossein Rouhani
- grid.17089.370000 0001 2190 316XDepartment of Mechanical Engineering, University of Alberta, Edmonton, AB Canada
| | - Andrew R. Martin
- grid.17089.370000 0001 2190 316XDepartment of Mechanical Engineering, University of Alberta, Edmonton, AB Canada
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Du B, Tandoc MC, Mack ML, Siegel JA. Indoor CO 2 concentrations and cognitive function: A critical review. INDOOR AIR 2020; 30:1067-1082. [PMID: 32557862 DOI: 10.1111/ina.12706] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 06/06/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
Poor indoor air quality indicated by elevated indoor CO2 concentrations has been linked with impaired cognitive function, yet current findings of the cognitive impact of CO2 are inconsistent. This review summarizes the results from 37 experimental studies that conducted objective cognitive tests with manipulated CO2 concentrations, either through adding pure CO2 or adjusting ventilation rates (the latter also affects other indoor pollutants). Studies with varied designs suggested that both approaches can affect multiple cognitive functions. In a subset of studies that meet objective criteria for strength and consistency, pure CO2 at a concentration common in indoor environments was only found to affect high-level decision-making measured by the Strategic Management Simulation battery in non-specialized populations, while lower ventilation and accumulation of indoor pollutants, including CO2 , could reduce the speed of various functions but leave accuracy unaffected. Major confounding factors include variations in cognitive assessment methods, study designs, individual and populational differences in subjects, and uncertainties in exposure doses. Accordingly, future research is suggested to adopt direct air delivery for precise control of CO2 inhalation, include brain imaging techniques to better understand the underlying mechanisms that link CO2 and cognitive function, and explore the potential interaction between CO2 and other environmental stimuli.
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Affiliation(s)
- Bowen Du
- Department of Civil and Mineral Engineering, University of Toronto, Toronto, Canada
| | - Marlie C Tandoc
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael L Mack
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeffrey A Siegel
- Department of Civil and Mineral Engineering, University of Toronto, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
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Duan M, Liu L, Da G, Géhin E, Nielsen PV, Weinreich UM, Lin B, Wang Y, Zhang T, Sun W. Measuring the administered dose of particles on the facial mucosa of a realistic human model. INDOOR AIR 2020; 30:108-116. [PMID: 31608493 DOI: 10.1111/ina.12612] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/22/2019] [Accepted: 10/10/2019] [Indexed: 05/20/2023]
Abstract
Exposure to particulate contaminants can cause serious adverse health effects. Deposition on the facial mucosa is an important path of exposure, but it is difficult to conduct direct dose measurement on real human subjects. In this study, we propose an in vitro method to assess the administered doses of micron-sized particles on the eyes and lips in which computed tomographic scanning and three-dimensional printing were used to create a model that includes a face, oropharynx, trachea, the first five generations of bronchi, and lung volume. This realistic model of a face and airway was exposed to monodispersed fluorescent particles released from an incoming jet. The administered dose of particles deposited upon the eyes and lips, as quantified by fluorescence intensity, was determined via a standard wiping protocol. The results show that, in this scenario, the administered doses normalized by source were 2.15%, 1.02%, 0.88%, 2.13%, and 1.55% for 0.6-, 1.0-, 2.0-, 3.0-, and 5.0-µm particles, respectively. The administered dose of large particles on the mucosa within a given exposure time has great significance. Moreover, the lips suffer a much greater risk of exposure than the eyes and account for more than 80% of total facial mucosa deposition. Our study provides a fast and economical method to assess the administered dose on the facial mucosa on an individual basis.
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Affiliation(s)
- Mengjie Duan
- Department of Building Science, School of Architecture, Tsinghua University, Beijing, China
- Université Paris-Est, CERTES (EA 3481), UPEC, Créteil, France
| | - Li Liu
- Department of Building Science, School of Architecture, Tsinghua University, Beijing, China
- State Key laboratory of Green Building in Western China, Xi'an University of Architecture and Technology, Xi'an, China
- Department of Civil Engineering, Aalborg University, Aalborg, Denmark
| | - Guillaume Da
- Université Paris-Est, CERTES (EA 3481), UPEC, Créteil, France
| | - Evelyne Géhin
- Université Paris-Est, CERTES (EA 3481), UPEC, Créteil, France
| | - Peter V Nielsen
- Department of Civil Engineering, Aalborg University, Aalborg, Denmark
| | - Ulla M Weinreich
- Department of Respiratory Diseases, Aalborg University Hospital, Aalborg, Denmark
- The Clinical Institute, Aalborg University, Aalborg, Denmark
| | - Borong Lin
- Department of Building Science, School of Architecture, Tsinghua University, Beijing, China
| | - Yi Wang
- State Key laboratory of Green Building in Western China, Xi'an University of Architecture and Technology, Xi'an, China
- School of Building Services Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, China
| | - Ting Zhang
- Department of Mechanical Engineering, Biomanufacturing Center, Tsinghua University, Beijing, China
| | - Wei Sun
- Department of Mechanical Engineering, Biomanufacturing Center, Tsinghua University, Beijing, China
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Tang JW, Hoyle E, Moran S, Pareek M. Near-Patient Sampling to Assist Infection Control-A Case Report and Discussion. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E238. [PMID: 29385031 PMCID: PMC5858307 DOI: 10.3390/ijerph15020238] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 01/08/2023]
Abstract
Air sampling as an aid to infection control is still in an experimental stage, as there is no consensus about which air samplers and pathogen detection methods should be used, and what thresholds of specific pathogens in specific exposed populations (staff, patients, or visitors) constitutes a true clinical risk. This case report used a button sampler, worn or held by staff or left free-standing in a fixed location, for environmental sampling around a child who was chronically infected by a respiratory adenovirus, to determine whether there was any risk of secondary adenovirus infection to the staff managing the patient. Despite multiple air samples taken on difference days, coinciding with high levels of adenovirus detectable in the child's nasopharyngeal aspirates (NPAs), none of the air samples contained any detectable adenovirus DNA using a clinically validated diagnostic polymerase chain reaction (PCR) assay. Although highly sensitive, in-house PCR assays have been developed to detect airborne pathogen RNA/DNA, it is still unclear what level of specific pathogen RNA/DNA constitutes a true clinical risk. In this case, the absence of detectable airborne adenovirus DNA using a conventional diagnostic assay removed the requirement for staff to wear surgical masks and face visors when they entered the child's room. No subsequent staff infections or outbreaks of adenovirus have so far been identified.
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Affiliation(s)
- Julian W Tang
- Clinical Microbiology, University Hospitals of Leicester NHS Trust, Leicester LE1 5WW, UK.
- Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 7RH, UK.
| | - Elizabeth Hoyle
- Infection Prevention and Control, University Hospitals of Leicester NHS Trust, Leicester LE1 5WW, UK.
| | - Sammy Moran
- Leicester Children's Hospital, University Hospitals of Leicester NHS Trust, Leicester LE1 5WW, UK.
| | - Manish Pareek
- Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 7RH, UK.
- Infectious Diseases Unit, University Hospitals of Leicester NHS Trust, Leicester LE1 5WW, UK.
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