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Pratt AA, Brown GD, Perencevich EN, Diekema DJ, Nonnenmann MW. Comparison of virus aerosol concentrations across a face shield worn on a healthcare personnel during a simulated patient cough. Infect Control Hosp Epidemiol 2024; 45:221-226. [PMID: 37609833 DOI: 10.1017/ice.2023.130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
BACKGROUND Patients diagnosed with coronavirus disease 2019 (COVID-19) aerosolize severe acute respiratory coronavirus virus 2 (SARS-CoV-2) via respiratory efforts, expose, and possibly infect healthcare personnel (HCP). To prevent transmission of SARS-CoV-2 HCP have been required to wear personal protective equipment (PPE) during patient care. Early in the COVID-19 pandemic, face shields were used as an approach to control HCP exposure to SARS-CoV-2, including eye protection. METHODS An MS2 bacteriophage was used as a surrogate for SARS-CoV-2 and was aerosolized using a coughing machine. A simulated HCP wearing a disposable plastic face shield was placed 0.41 m (16 inches) away from the coughing machine. The aerosolized virus was sampled using SKC biosamplers on the inside (near the mouth of the simulated HCP) and the outside of the face shield. The aerosolized virus collected by the SKC Biosampler was analyzed using a viability assay. Optical particle counters (OPCs) were placed next to the biosamplers to measure the particle concentration. RESULTS There was a statistically significant reduction (P < .0006) in viable virus concentration on the inside of the face shield compared to the outside of the face shield. The particle concentration was significantly lower on the inside of the face shield compared to the outside of the face shield for 12 of the 16 particle sizes measured (P < .05). CONCLUSIONS Reductions in virus and particle concentrations were observed on the inside of the face shield; however, viable virus was measured on the inside of the face shield, in the breathing zone of the HCP. Therefore, other exposure control methods need to be used to prevent transmission from virus aerosol.
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Affiliation(s)
- Alessandra A Pratt
- University of Iowa, Department of Occupational and Environmental Health, Iowa City, Iowa
- Iowa City Veterans Affairs Health Care System, Iowa City, Iowa
| | - Grant D Brown
- Department of Biostatistics, University of Iowa, Iowa City, Iowa
| | - Eli N Perencevich
- Iowa City Veterans Affairs Health Care System, Iowa City, Iowa
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Daniel J Diekema
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
- Department of Medicine, Maine Medical Center, PortlandMaine
| | - Matthew W Nonnenmann
- Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, Nebraska
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Shrimpton AJ, Brown V, Vassallo J, Nolan JP, Soar J, Hamilton F, Cook TM, Bzdek BR, Reid JP, Makepeace CH, Deutsch J, Ascione R, Brown JM, Benger JR, Pickering AE. A quantitative evaluation of aerosol generation during cardiopulmonary resuscitation. Anaesthesia 2024; 79:156-167. [PMID: 37921438 PMCID: PMC10952244 DOI: 10.1111/anae.16162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2023] [Indexed: 11/04/2023]
Abstract
It is unclear if cardiopulmonary resuscitation is an aerosol-generating procedure and whether this poses a risk of airborne disease transmission to healthcare workers and bystanders. Use of airborne transmission precautions during cardiopulmonary resuscitation may confer rescuer protection but risks patient harm due to delays in commencing treatment. To quantify the risk of respiratory aerosol generation during cardiopulmonary resuscitation in humans, we conducted an aerosol monitoring study during out-of-hospital cardiac arrests. Exhaled aerosol was recorded using an optical particle sizer spectrometer connected to the breathing system. Aerosol produced during resuscitation was compared with that produced by control participants under general anaesthesia ventilated with an equivalent respiratory pattern to cardiopulmonary resuscitation. A porcine cardiac arrest model was used to determine the independent contributions of ventilatory breaths, chest compressions and external cardiac defibrillation to aerosol generation. Time-series analysis of participants with cardiac arrest (n = 18) demonstrated a repeating waveform of respiratory aerosol that mapped to specific components of resuscitation. Very high peak aerosol concentrations were generated during ventilation of participants with cardiac arrest with median (IQR [range]) 17,926 (5546-59,209 [1523-242,648]) particles.l-1 , which were 24-fold greater than in control participants under general anaesthesia (744 (309-2106 [23-9099]) particles.l-1 , p < 0.001, n = 16). A substantial rise in aerosol also occurred with cardiac defibrillation and chest compressions. In a complimentary porcine model of cardiac arrest, aerosol recordings showed a strikingly similar profile to the human data. Time-averaged aerosol concentrations during ventilation were approximately 270-fold higher than before cardiac arrest (19,410 (2307-41,017 [104-136,025]) vs. 72 (41-136 [23-268]) particles.l-1 , p = 0.008). The porcine model also confirmed that both defibrillation and chest compressions generate high concentrations of aerosol independent of, but synergistic with, ventilation. In conclusion, multiple components of cardiopulmonary resuscitation generate high concentrations of respiratory aerosol. We recommend that airborne transmission precautions are warranted in the setting of high-risk pathogens, until the airway is secured with an airway device and breathing system with a filter.
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Affiliation(s)
- A. J. Shrimpton
- Anaesthesia, Pain and Critical Care Sciences, School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | - V. Brown
- Critical Care, South Western Ambulance Service NHS Foundation TrustUK
- Great Western Air Ambulance CharityBristolUK
| | - J. Vassallo
- Institute of Naval MedicineGosportUK
- Academic Department of Military Emergency MedicineRoyal Centre for Defence MedicineBirminghamUK
| | - J. P. Nolan
- University of Warwick, Warwick Medical SchoolCoventryUK
- Department of Anaesthesia and Intensive Care MedicineRoyal United HospitalBathUK
| | - J. Soar
- Department of Anaesthesia and Intensive Care MedicineNorth Bristol NHS TrustBristolUK
| | - F. Hamilton
- MRC Integrative Epidemiology UnitUniversity of BristolUK
| | - T. M. Cook
- Department of Anaesthesia and Intensive Care MedicineRoyal United HospitalBathUK
| | - B. R. Bzdek
- School of ChemistryUniversity of BristolBristolUK
| | - J. P. Reid
- School of ChemistryUniversity of BristolBristolUK
| | - C. H. Makepeace
- Langford Vets and Translational Biomedical Research CentreUniversity of BristolUK
| | - J. Deutsch
- Langford Vets and Translational Biomedical Research CentreUniversity of BristolUK
| | - R. Ascione
- Translational Biomedical Research CentreUniversity of BristolBristolUK
- University Hospital Bristol Weston NHS TrustBristolUK
| | - J. M. Brown
- Department of Anaesthesia and Intensive Care MedicineNorth Bristol NHS TrustBristolUK
| | - J. R. Benger
- Faculty of Health and Applied SciencesUniversity of the West of EnglandBristolUK
| | - A. E. Pickering
- Department of AnaesthesiaUniversity Hospitals Bristol and WestonBristolUK
- Anaesthesia, Pain and Critical Care Sciences, School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
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Sanmark E, Oksanen LAH, Rantanen N, Lahelma M, Anttila VJ, Lehtonen L, Hyvärinen A, Geneid A. Aerosol generation during coughing: an observational study. J Laryngol Otol 2023; 137:442-447. [PMID: 35543098 PMCID: PMC10040286 DOI: 10.1017/s0022215122001165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Coronavirus disease 2019 has highlighted the lack of knowledge on aerosol exposure during respiratory activity and aerosol-generating procedures. This study sought to determine the aerosol concentrations generated by coughing to better understand, and to set a standard for studying, aerosols generated in medical procedures. METHODS Aerosol exposure during coughing was measured in 37 healthy volunteers in the operating theatre with an optical particle sizer, from 40 cm, 70 cm and 100 cm distances. RESULTS Altogether, 306 volitional and 15 involuntary coughs were measured. No differences between groups were observed. CONCLUSION Many medical procedures are expected to generate aerosols; it is unclear whether they are higher risk than normal respiratory activity. The measured aerosol exposure can be used to determine the risk for significant aerosol generation during medical procedures. Considerable variation of aerosol generation during cough was observed between individuals, but whether cough was volitional or involuntary made no difference to aerosol production.
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Affiliation(s)
- E Sanmark
- Facultie of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology and Phoniatrics - Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland
| | - L A H Oksanen
- Facultie of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology and Phoniatrics - Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland
| | - N Rantanen
- Facultie of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology and Phoniatrics - Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland
| | - M Lahelma
- Facultie of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology and Phoniatrics - Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland
- Faculties of Science, Mathematics and Statistics, University of Helsinki, Helsinki, Finland
| | - V-J Anttila
- Facultie of Medicine, University of Helsinki, Helsinki, Finland
- HUS Inflammation Center, Helsinki University Hospital, Helsinki, Finland
| | - L Lehtonen
- Facultie of Medicine, University of Helsinki, Helsinki, Finland
- HUS Diagnostic Center, HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - A Hyvärinen
- Finnish Meteorological Institute, Helsinki, Finland
| | - A Geneid
- Facultie of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology and Phoniatrics - Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland
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Sultan S. Gastrointestinal Endoscopy in Patients with Coronavirus Disease 2019: Indications, Findings, and Safety. Gastroenterol Clin North Am 2023; 52:157-172. [PMID: 36813423 PMCID: PMC9678816 DOI: 10.1016/j.gtc.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The coronavirus disease 2019 (COVID-19) pandemic has changed the practice of gastroenterology and how we perform endoscopy. As with any new or emerging pathogen, early in the pandemic, there was limited evidence and understanding of disease transmission, limited testing capability, and resource constraints, especially availability of personal protective equipment (PPE). As the COVID-19 pandemic progressed, enhanced protocols with particular emphasis on assessing the risk status of patients and proper use of PPE have been incorporated into routine patient care. The COVID-19 pandemic has taught us important lessons for the future of gastroenterology and endoscopy.
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Affiliation(s)
- Shahnaz Sultan
- Division of Gastroenterology, Hepatology and Nutrition, University of Minnesota, 420 Delaware Street Southeast, MMC 36, Minneapolis, MN 55455, USA.
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Schreiber J, Brüggmann D, Braun M, Groneberg DA. The measuring aerosol spreading during countermeasures (MASC) study presents an automated system to investigate face mask efficacy and other aerosol countermeasures in varying environments. Sci Rep 2022; 12:21349. [PMID: 36494375 PMCID: PMC9734563 DOI: 10.1038/s41598-022-25210-5] [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: 09/29/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022] Open
Abstract
The COVID-19 pandemic exemplified the importance of research on personal protective equipment. In specific, understanding how effective surgical masks or particulate filter respirators are at reducing the transmission of infectious diseases has suddenly become one of the most pressing issues for legislators, regulators, and everyday life. However, there was a lack of available scientific platforms to assess this issue. Therefore, we designed and built a system entitled MASC: measuring aerosol spreading during countermeasures. This platform allows the simulation of various everyday situations and evaluation of the efficacy of masks and respirators in reducing the amount of inhaled particulate matter from the air. Furthermore, MASC can be used to investigate how aerosols propagate in closed spaces, such as offices or classrooms. It can be used to generate aerosols on command and control the room temperature, humidity, and wind speed. Up to four laser aerosol spectrometers can be read simultaneously, and a camera can automatically take pictures to evaluate the efficacy of countermeasures to prevent the spread of aerosols. The aerosol generation, measurement periods, and the number of repetitions for an experiment can be configured digitally and are executed by a computer automatically. A website displays the data in real time and allows monitoring of the experiment. Upon completion, statistical values are calculated automatically to accelerate the evaluation of the gathered data. Codes and technical drawings in this present methodology publication are open source and can be used by the scientific community to establish similar systems.
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Affiliation(s)
- Johannes Schreiber
- grid.7839.50000 0004 1936 9721Institute of Occupational Medicine, Social Medicine, Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt Am Main, Germany
| | - Dörthe Brüggmann
- grid.7839.50000 0004 1936 9721Institute of Occupational Medicine, Social Medicine, Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt Am Main, Germany
| | - Markus Braun
- grid.7839.50000 0004 1936 9721Institute of Occupational Medicine, Social Medicine, Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt Am Main, Germany
| | - David A. Groneberg
- grid.7839.50000 0004 1936 9721Institute of Occupational Medicine, Social Medicine, Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt Am Main, Germany
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Argyropoulos CD, Skoulou V, Efthimiou G, Michopoulos AK. Airborne transmission of biological agents within the indoor built environment: a multidisciplinary review. AIR QUALITY, ATMOSPHERE, & HEALTH 2022; 16:477-533. [PMID: 36467894 PMCID: PMC9703444 DOI: 10.1007/s11869-022-01286-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
The nature and airborne dispersion of the underestimated biological agents, monitoring, analysis and transmission among the human occupants into building environment is a major challenge of today. Those agents play a crucial role in ensuring comfortable, healthy and risk-free conditions into indoor working and leaving spaces. It is known that ventilation systems influence strongly the transmission of indoor air pollutants, with scarce information although to have been reported for biological agents until 2019. The biological agents' source release and the trajectory of airborne transmission are both important in terms of optimising the design of the heating, ventilation and air conditioning systems of the future. In addition, modelling via computational fluid dynamics (CFD) will become a more valuable tool in foreseeing risks and tackle hazards when pollutants and biological agents released into closed spaces. Promising results on the prediction of their dispersion routes and concentration levels, as well as the selection of the appropriate ventilation strategy, provide crucial information on risk minimisation of the airborne transmission among humans. Under this context, the present multidisciplinary review considers four interrelated aspects of the dispersion of biological agents in closed spaces, (a) the nature and airborne transmission route of the examined agents, (b) the biological origin and health effects of the major microbial pathogens on the human respiratory system, (c) the role of heating, ventilation and air-conditioning systems in the airborne transmission and (d) the associated computer modelling approaches. This adopted methodology allows the discussion of the existing findings, on-going research, identification of the main research gaps and future directions from a multidisciplinary point of view which will be helpful for substantial innovations in the field.
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Affiliation(s)
| | - Vasiliki Skoulou
- B3 Challenge Group, Chemical Engineering, School of Engineering, University of Hull, Cottingham Road, Hull, HU6 7RX UK
| | - Georgios Efthimiou
- Centre for Biomedicine, Hull York Medical School, University of Hull, Cottingham Road, Hull, HU6 7RX UK
| | - Apostolos K. Michopoulos
- Energy & Environmental Design of Buildings Research Laboratory, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
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7
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Chew HS, Tan M, Sanchalika A, Tan G, Ho EC, Ang BSP, Agrawal R, Yeo SB. Innovative dual-function protective scope mask and filtration system for aerosol generating ENT scope procedures. Laryngoscope Investig Otolaryngol 2022; 7:1376-1383. [PMID: 36258853 PMCID: PMC9575126 DOI: 10.1002/lio2.913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/05/2022] [Accepted: 08/14/2022] [Indexed: 11/07/2022] Open
Abstract
Background Aerosol-generating procedures (AGPs), such as nasoendoscopy, are considered high-risk during the COVID-19 pandemic due to risk of virus aerosol transmission. We aim to evaluate the efficacy of an innovative system in reduction of aerosol contamination. Methods Pilot study involving 15 healthy volunteers performing aerosol-generating activities with the prototype, compared with and without a standard surgical mask. Results We found an increased frequency of smaller-sized particle emissions for all four expiratory activities. The particle emission rate with the prototype mask was significantly slower over time for the smallest sized particle (0.3 μm) during breathing, speaking and singing compared with similar activities without the mask (p < .05). We found similar trends for coughing for larger particles but that did not reach statistical significance. Conclusion The innovation offers good protection against aerosol transmission through the physical barrier of the mask, the negative pressure environment within the mask, and the unit's dual filtration function. Level of evidence Level 2b.
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Affiliation(s)
- Hui Sing Chew
- Department of OtorhinolaryngologyTan Tock Seng HospitalSingaporeSingapore
| | - Marcus Tan
- The Biofactory Pte LtdSingaporeSingapore
| | - Acharyya Sanchalika
- Clinical Research and Innovation Office, Tan Tock Seng HospitalSingaporeSingapore
| | | | - Eu Chin Ho
- Department of OtorhinolaryngologyTan Tock Seng HospitalSingaporeSingapore
| | - Brenda Sze Peng Ang
- Department of Infectious DiseasesTan Tock Seng HospitalSingaporeSingapore
- National Centre for Infectious DiseasesSingaporeSingapore
| | - Rupesh Agrawal
- National Healthcare Group Eye Institute, Tan Tock Seng HospitalSingaporeSingapore
- Singapore Eye Research InstituteSingaporeSingapore
| | - Seng Beng Yeo
- Department of OtorhinolaryngologyTan Tock Seng HospitalSingaporeSingapore
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8
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Monroe LW, Johnson JS, Gutstein HB, Lawrence JP, Lejeune K, Sullivan RC, Jen CN. Preventing spread of aerosolized infectious particles during medical procedures: A lab-based analysis of an inexpensive plastic enclosure. PLoS One 2022; 17:e0273194. [PMID: 36137079 PMCID: PMC9499281 DOI: 10.1371/journal.pone.0273194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 08/03/2022] [Indexed: 11/25/2022] Open
Abstract
Severe viral respiratory diseases, such as SARS-CoV-2, are transmitted through aerosol particles produced by coughing, talking, and breathing. Medical procedures including tracheal intubation, extubation, dental work, and any procedure involving close contact with a patient’s airways can increase exposure to infectious aerosol particles. This presents a significant risk for viral exposure of nearby healthcare workers during and following patient care. Previous studies have examined the effectiveness of plastic enclosures for trapping aerosol particles and protecting health-care workers. However, many of these enclosures are expensive or are burdensome for healthcare workers to work with. In this study, a low-cost plastic enclosure was designed to reduce aerosol spread and viral transmission during medical procedures, while also alleviating issues found in the design and use of other medical enclosures to contain aerosols. This enclosure is fabricated from clear polycarbonate for maximum visibility. A large single-side cutout provides health care providers with ease of access to the patient with a separate cutout for equipment access. A survey of medical providers in a local hospital network demonstrated their approval of the enclosure’s ease of use and design. The enclosure with appropriate plastic covers reduced total escaped particle number concentrations (diameter > 0.01 μm) by over 93% at 8 cm away from all openings. Concentration decay experiments indicated that the enclosure without active suction should be left on the patient for 15–20 minutes following a tracheal manipulation to allow sufficient time for >90% of aerosol particles to settle upon interior surfaces. This decreases to 5 minutes when 30 LPM suction is applied. This enclosure is an inexpensive, easily implemented additional layer of protection that can be used to help contain infectious or otherwise potentially hazardous aerosol particles while providing access into the enclosure.
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Affiliation(s)
- Luke W. Monroe
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Jack S. Johnson
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Howard B. Gutstein
- Anesthesiology Institute, Allegheny Health Network, Pittsburgh, PA, United States of America
| | - John P. Lawrence
- Anesthesiology Institute, Allegheny Health Network, Pittsburgh, PA, United States of America
| | - Keith Lejeune
- Anesthesiology Institute, Allegheny Health Network, Pittsburgh, PA, United States of America
| | - Ryan C. Sullivan
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, United States of America
- * E-mail:
| | - Coty N. Jen
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, United States of America
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Wang Q, Gu J, An T. The emission and dynamics of droplets from human expiratory activities and COVID-19 transmission in public transport system: A review. BUILDING AND ENVIRONMENT 2022; 219:109224. [PMID: 35645454 PMCID: PMC9126829 DOI: 10.1016/j.buildenv.2022.109224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 05/03/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
The public transport system, containing a large number of passengers in enclosed and confined spaces, provides suitable conditions for the spread of respiratory diseases. Understanding how diseases are transmitted in public transport environment is of vital importance to public health. However, this is a highly multidisciplinary matter and the related physical processes including the emissions of respiratory droplets, the droplet dynamics and transport pathways, and subsequently, the infection risk in public transport, are poorly understood. To better grasp the complex processes involved, a synthesis of current knowledge is required. Therefore, we conducted a review on the behaviors of respiratory droplets in public transport system, covering a wide scope from the emission profiles of expiratory droplets, the droplet dynamics and transport, to the transmission of COVID-19 in public transport. The literature was searched using related keywords in Web of Science and PubMed and screened for suitability. The droplet size is a key parameter in determining the deposition and evaporation, which together with the exhaled air velocity largely determines the horizontal travel distance. The potential transmission route and transmission rate in public transport as well as the factors influencing the virus-laden droplet behaviors and virus viability (such as ventilation system, wearing personal protective equipment, air temperature and relative humidity) were also discussed. The review also suggests that future studies should address the uncertainties in droplet emission profiles associated with the measurement techniques, and preferably build a database based on a unified testing protocol. Further investigations based on field measurements and modeling studies into the influence of different ventilation systems on the transmission rate in public transport are also needed, which would provide scientific basis for controlling the transmission of diseases.
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Affiliation(s)
- Qiaoqiao Wang
- Institute for Environmental and Climate Research, Jinan University, 511443, Guangzhou, China
- Guangdong-Hong Kong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, 511443, Guangzhou, China
| | - Jianwei Gu
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, 510006, Guangzhou, China
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, 510006, Guangzhou, China
| | - Taicheng An
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, 510006, Guangzhou, China
- Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, School of Environmental Science and Engineering, Guangdong University of Technology, 510006, Guangzhou, China
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10
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Quantifying the Risk to Health Care Workers of Cough as an Aerosol Generating Event in an Ambulance Setting: A Research Report. Prehosp Disaster Med 2022; 37:515-519. [PMID: 35713106 PMCID: PMC9280060 DOI: 10.1017/s1049023x22000917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Introduction and Objective: United Kingdom Health Security Agency (UKHSA) guidance related to mask use for health care workers in a non-aerosol generating procedure (AGP) setting has remained as Level 2 water repellent paper mask (surgical mask) only. Energetic respiratory events, such as coughing, can generate vast numbers of droplets and aerosols. Coughing, considered to be a non-AGP event, frequently occurs in the relatively small, confined space of an ambulance (∼25 m3). The report seeks to explore whether existing research can provide an indication of the risk to ambulance staff, via aerosol transmission, of an acute respiratory infection (ARI) during a coughing event within the clinical setting of an ambulance. Methods: International bibliographic databases were searched (CINAHL Plus, SCOPUS, PubMed, and CENTRAL) using appropriate search strings and a combination of relevant medical subject headings with appropriate truncation. Methodological filters were not applied. Papers without an English language abstract were excluded from the review. Grey literature was sought by searching specialist databases OpenGrey and GreyNet, as well as key organizations’ websites. The initial search identified 2,405 articles. Following screening, along with forward and backward citation of key papers identified within the literature search, 36 papers were deemed eligible for the scoping review. Discussion: Attempts to replicate a clinical environment to investigate the risk of transmission of airborne viruses to health care workers during a coughing event provided evidence for the generation of respirable aerosol particles and thus potential transmission of pathogens. In cases of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), potential to infect versus true airborne transmission is a debate that continues, but there is general consensus that a large variation of cough characteristics and aerosol generation amongst individuals exists. Studies widely endorsed face masks as a source control device, but there were conflicting views about the impact of mask leakage. Conclusion: Further research is required to provide clarity of the risk to health care workers when caring for a coughing patient in the confined clinical ambulance setting and to provide an evidence base to assist in the determination of appropriate respiratory protective equipment (RPE).
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Vadlamudi G, Thirumalaikumaran SK, Chakravortty D, Saha A, Basu S. Penetration and aerosolization of cough droplet spray through face masks: A unique pathway of transmission of infection. PHYSICS OF FLUIDS 2022; 34. [DOI: 10.1063/5.0093297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
The advent of the COVID-19 pandemic has necessitated the use of face masks, making them an integral part of the daily routine. Face masks occlude the infectious droplets during any respiratory event contributing to source control. In the current study, spray impingement experiments were conducted on porous surfaces like masks having a different porosity, pore size, and thickness. The spray mimics actual cough or a mild sneeze with respect to the droplet size distribution (20–500 μm) and velocity scale (0–14 m/s), which makes the experimental findings physiologically realistic. The penetration dynamics through the mask showed that droplets of all sizes beyond a critical velocity penetrate through the mask fabric and atomize into daughter droplets in the aerosolization range, leading to harmful effects due to the extended airborne lifetime of aerosols. By incorporating spray characteristics along with surface tension and viscous dissipation of the fluid passing through the mask, multi-step penetration criteria have been formulated. The daughter droplet size and velocity distribution after atomizing through multi-layered masks and its effects have been discussed. Moreover, the virus-emulating particle-laden surrogate respiratory droplets are used in impingement experiments to study the filtration and entrapment of virus-like nanoparticles in the mask. Furthermore, the efficacy of the mask from the perspective of a susceptible person has been investigated.
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Affiliation(s)
- Gautham Vadlamudi
- Department of Mechanical Engineering, Indian Institute of Science 1 , Bangalore, Karnataka 560012, India
| | - S. K. Thirumalaikumaran
- Department of Mechanical Engineering, Indian Institute of Science 1 , Bangalore, Karnataka 560012, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Indian Institute of Science 2 , Bangalore, Karnataka 560012, India
- Center of Biosystems Science and Engineering, Indian Institute of Science 3 , Bangalore, Karnataka 560012, India
| | - Abhishek Saha
- Department of Mechanical and Aerospace Engineering, University of California San Diego 4 , La Jolla, California 92093, USA
| | - Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science 1 , Bangalore, Karnataka 560012, India
- Interdisciplinary Centre for Energy Research (ICER), Indian Institute of Science 5 , Bangalore, Karnataka 560012, India
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12
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de Araujo CM, Guariza-Filho O, Gonçalves FM, Basso IB, Schroder AGD, Cavalcante-Leão BL, Ravazzi GC, Zeigelboim BS, Stechman-Neto J, Santos RS. Front lines of the COVID-19 pandemic: what is the effectiveness of using personal protective equipment in health service environments?-a systematic review. Int Arch Occup Environ Health 2022; 95:7-24. [PMID: 34674034 PMCID: PMC8528650 DOI: 10.1007/s00420-021-01775-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 01/08/2021] [Indexed: 01/09/2023]
Abstract
PURPOSE This systematic review aimed to evaluate the effectiveness of the use of personal protective equipment (PPE) in closed environments, similar to waiting or exam rooms of healthcare facilities, in the face of exposure to a bioaerosol. METHODS Combinations of words were selected for six electronic databases and for the gray literature. To consider the eligibility of the studies to be included/excluded, the acronym "PECOS" was used: humans and/or experimental models that simulate aerosol (Population); aerosol exposure and the use of masks/respirators (exposition/intervention); controlled or not controlled (comparison); effectiveness of PPE and the receiver exposure (outcomes); and randomized clinical studies or not, observational or laboratory simulation studies (Studies design). RESULTS A total of 4820 references were retrieved by the search strategy. Thirty-five articles were selected for complete reading, of which 13 articles were included for qualitative synthesis. A surgical mask or N95 respirator reduced the risk of transmission, even over short distances. The use of masks, even those with less filtering power, when used by all individuals in the same environment is more effective in reducing risk than the use of respirators with high filtering power for only some of the individuals present. CONCLUSION The use of mask in closed environments is effective in reducing the risk of transmission and contagion of a contaminated bioaerosol, with greater effectiveness when these devices are used by the source and receiver, regardless of the equipment's filtering power. (PROSPERO 2020 CRD 42020183759).
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Affiliation(s)
| | - Odilon Guariza-Filho
- Department of Orthodontics, School of Health and Bioscience, Pontifícia Universidade Católica do Paraná, Street Imaculada Conceição, 1155, Prado Velho, Curitiba, Paraná 80215-901 Brazil
| | - Flavio Magno Gonçalves
- Postgraduate Program in Communication Disorders, Tuiuti University of Paraná, Curitiba, Brazil
| | - Isabela Bittencourt Basso
- Postgraduate Program in Dentistry, Pontifícia Universidade Católica do Paraná, Curitiba, Paraná Brazil
| | | | | | - Glória Cortz Ravazzi
- Postgraduate Program in Communication Disorders, Tuiuti University of Paraná, Curitiba, Brazil
| | | | - José Stechman-Neto
- Postgraduate Program in Communication Disorders, Tuiuti University of Paraná, Curitiba, Brazil
| | - Rosane Sampaio Santos
- Postgraduate Program in Communication Disorders, Tuiuti University of Paraná, Curitiba, Brazil
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13
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Srivastava A, Andersen MR, Alshehri AM, Lara B, Bashiri R, Li G, Chambers MS. Effectiveness of a Chairside Acrylic Adjustment Cabinet in Reducing Dental Acrylic Debris and Aerosols. J Prosthodont 2021; 31:488-495. [PMID: 34855263 DOI: 10.1111/jopr.13463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2021] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Chairside prosthesis adjustment procedures generate contaminated acrylic particle debris that include visible splatter (particles >50 μm) as well as invisible aerosols (<50 µm). The purpose of this study was to evaluate the effectiveness of a chairside acrylic adjustment cabinet (CAAC) in reducing airborne aerosol particles (<10 µm) and visible acrylic debris, time required for airborne aerosols to return to baseline levels after an acrylic adjustment procedure, and the effect on operatory turnover time. MATERIALS AND METHODS A total of 40 acrylic adjustment procedures were carried out in a simulated setting with (experiment) and without (control) a CAAC. Standardized acrylic samples of self-polymerized, and heat polymerized polymethylmethacrylate resins, Triad™ and Fastray™ custom tray materials were evaluated. Airborne aerosol measurements were done using a handheld Lase.r Particle Counter for absolute particle counts of sizes 0.3, 0.5, 1.0, 2.5, 5.0, and 10.0 μm before, during, and immediately after adjustment and 10 minutes postadjustment. Spread of aerosols was assessed at three distinct locations within the dental operatory specific to the provider, the patient, and the caregiver/guest. Visible acrylic debris and operatory turnover time were evaluated immediately postadjustments by a blinded investigator. Repeated measures ANOVA was used to estimate group effect, time effect and interaction between group and time for air particle analysis. Independent samples T-tests were used for group differences between operatory turnover time, and time for aerosols to return to baseline. Chi-square test was used for visible surface analysis. RESULTS In the control group, total aerosol particle counts increased from 6542.7 ± 162.6 particles at baseline to 598378.7 ± 586363.2 and 367569.9 ± 432220.8 particles during and immediately postadjustment, respectively. Adjustments made in the experiment group led to significantly reduced aerosol counts during (97738.9 ± 97866.5) and immediately postadjustment (19786.5 ± 14004.9; F = 17.8, p = 0.006). Similar trends were noted for the patient and guest positions. Time for aerosol particles to return to baseline was significantly lower in the experiment group (20.56 ± 14.5 minutes) compared to the control group (37.9 ± 31.96 minutes; p = 0.03). Visible acrylic debris analysis showed a significant decrease of 78% in the experiment group (p < 0.001). No significant differences were noted in operatory turnover time between the two groups (p = 0.61). CONCLUSIONS Acrylic adjustment procedures generated aerosols of particle sizes less than 10 µm and were measured in significant quantities throughout the dental operatory for up to 115 minutes. Chairside acrylic adjustment cabinets significantly decreased airborne aerosols, visible acrylic particle debris, and reduced the time for airborne aerosols to return to baseline levels.
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Affiliation(s)
- Akanksha Srivastava
- Department of Surgery, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Michael R Andersen
- Department of Hospital Dentistry, Naval Medical Center, San Diego, CA, USA
| | - Abdulkareem M Alshehri
- Maxillofacial Prosthodontics Surgical Dentistry, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Bryan Lara
- Private practice, Inwood, West Virginia, USA
| | - Rafiullah Bashiri
- Division of Comprehensive Oral Health, Adams School of Dentistry, The University of North Carolina, Chapel Hill, NC, USA
| | - Guojun Li
- Department of Head and Neck Surgery, Division of Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Mark S Chambers
- Department of Head and Neck Surgery, Division of Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
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14
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Luu C, Chan M, Langga L, Bragg E, Rake A, Young C, Lau J, Guerrero E, Buan J, Chang T. Development of a Mannequin for Simulation-Based Trials Involving Respiratory Viral Spread During Respiratory Arrest and Cardiopulmonary Arrest Scenarios. Cureus 2021; 13:e20304. [PMID: 35028208 PMCID: PMC8744367 DOI: 10.7759/cureus.20304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2021] [Indexed: 11/12/2022] Open
Abstract
During the coronavirus disease 2019 (COVID-19) pandemic, mannequin models have been developed to mimic viral spread using fluorescent particles. These models use contraptions such as a spray gun or an exploding latex balloon to emanate a sudden acceleration of particles, simulating a "cough" reflex. No models have been developed to mimic passive aerosolization of viral particles during a cardiopulmonary arrest simulation. Our novel approach to aerosolization of simulated viral spread allows for a continuous flow of particles, which allows us to maintain components of high-fidelity team-based simulations. Our simulated model emanated GloGerm (Moab, UT) from the respiratory tract using a continuous nebulization chamber. Uniquely, the construction of our apparatus allowed for the ability to perform full, simulated cardiopulmonary resuscitation scenarios (such as chest compressions, bag-mask ventilation, and endotracheal intubation) on a high-fidelity mannequin while visualizing potential contamination spread at the conclusion of the simulation. Positive feedback from users included the ability to visualize particulate contamination after cardiopulmonary resuscitations in the context of personal protective equipment usage and roles in resuscitation (i.e. physician, respiratory therapist, nurse). Negative criticism towards the simulation included the lack of certain high-fidelity feedback markers of the mannequin (auscultating breath sounds and checking pulses) due to the construction of the particle aerosolization mechanism.
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Affiliation(s)
- Cindy Luu
- Department of Emergency Medicine, Children's Hospital Los Angeles, Los Angeles, USA
| | - Margaux Chan
- Las Madrinas Simulation Center, Children's Hospital Los Angeles, Los Angeles, USA
| | - Leo Langga
- Department of Respiratory Medicine, Children's Hospital Los Angeles, Los Angeles, USA
| | - Elizabeth Bragg
- Department of Anesthesiology Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, USA
| | - Alyssa Rake
- Department of Anesthesiology Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, USA
| | - Caulette Young
- Las Madrinas Simulation Center, Children's Hospital Los Angeles, Los Angeles, USA
| | - Jennifer Lau
- Department of Anesthesiology Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, USA
| | - Edward Guerrero
- Department of Respiratory Medicine, Children's Hospital Los Angeles, Los Angeles, USA
| | - Joshua Buan
- Department of Respiratory Medicine, Children's Hospital Los Angeles, Los Angeles, USA
| | - Todd Chang
- Department of Emergency Medicine, Children's Hospital Los Angeles, Los Angeles, USA
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15
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McGowan A, Laveneziana P, Bayat S, Beydon N, Boros PW, Burgos F, Fležar M, Franczuk M, Galarza MA, Kendrick AH, Lombardi E, Makonga-Braaksma J, McCormack MC, Plantier L, Stanojevic S, Steenbruggen I, Thompson B, Coates AL, Wanger J, Cockcroft DW, Culver B, Sylvester K, De Jongh F. International consensus on lung function testing during COVID-19 pandemic and beyond. ERJ Open Res 2021; 8:00602-2021. [PMID: 35261912 PMCID: PMC8607240 DOI: 10.1183/23120541.00602-2021] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 10/31/2021] [Indexed: 11/05/2022] Open
Abstract
COVID-19 has negatively affected the delivery of respiratory diagnostic services across the world due to the potential risk of disease transmission during lung function testing. Community prevalence, reoccurrence of COVID-19 surges, and the emergence of different variants of the SARS-CoV-2 virus have impeded attempts to restore services. Finding consensus on how to deliver safe lung function services for both patients attending and for staff performing the tests are of paramount importance.This international statement presents the consensus opinion of 23 experts in the field of lung function and respiratory physiology balanced with evidence from the reviewed literature. It describes a robust roadmap for restoration and continuity of lung function testing services during the COVID-19 pandemic and beyond.Important strategies presented in this consensus statement relate to the patient journey when attending for lung function tests. We discuss appointment preparation, operational and environmental issues, testing room requirements including mitigation strategies for transmission risk, requirement for improved ventilation, maintaining physical distance, and use of personal protection equipment. We also provide consensus opinion on precautions relating to specific tests, filters, management of special patient groups, and alternative options to testing in hospitals.The pandemic has highlighted how vulnerable lung function services are and forces us to re-think how long term mitigation strategies can protect our services during this and any possible future pandemic. This statement aspires to address the safety concerns that exist and provide strategies to make lung function tests and the testing environment safer when tests are required.
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16
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Lommel M, Froese V, Sieber M, Jentzsch M, Bierewirtz T, Hasirci Ü, Rese T, Seefeldt J, Schimek S, Kertzscher U, Paschereit CO. Novel measurement system for respiratory aerosols and droplets in indoor environments. INDOOR AIR 2021; 31:1860-1873. [PMID: 34096643 PMCID: PMC8242391 DOI: 10.1111/ina.12860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 04/14/2021] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
The SARS-CoV-2 pandemic has created a great demand for a better understanding of the spread of viruses in indoor environments. A novel measurement system consisting of one portable aerosol-emitting mannequin (emitter) and a number of portable aerosol-absorbing mannequins (recipients) was developed that can measure the spread of aerosols and droplets that potentially contain infectious viruses. The emission of the virus from a human is simulated by using tracer particles solved in water. The recipients inhale the aerosols and droplets and quantify the level of solved tracer particles in their artificial lungs simultaneously over time. The mobile system can be arranged in a large variety of spreading scenarios in indoor environments and allows for quantification of the infection probability due to airborne virus spreading. This study shows the accuracy of the new measurement system and its ability to compare aerosol reduction measures such as regular ventilation or the use of a room air purifier.
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Affiliation(s)
- Michael Lommel
- Biofluid Mechanics LaboratoryInstitute for Imaging Science and Computational Modelling in Cardiovascular MedicineCharité – Universitätsmedizin BerlinAugustenburger Platz 1BerlinBerlin13353Germany
| | - Vera Froese
- Biofluid Mechanics LaboratoryInstitute for Imaging Science and Computational Modelling in Cardiovascular MedicineCharité – Universitätsmedizin BerlinAugustenburger Platz 1BerlinBerlin13353Germany
| | - Moritz Sieber
- Institute of Fluid Dynamics and Technical AcousticsHermann‐Föttinger‐InstituteChair of Fluid DynamicsTU BerlinStraße des 17. Juni, 135BerlinBerlin10623Germany
| | - Marvin Jentzsch
- Institute of Fluid Dynamics and Technical AcousticsHermann‐Föttinger‐InstituteChair of Fluid DynamicsTU BerlinStraße des 17. Juni, 135BerlinBerlin10623Germany
| | - Tim Bierewirtz
- Biofluid Mechanics LaboratoryInstitute for Imaging Science and Computational Modelling in Cardiovascular MedicineCharité – Universitätsmedizin BerlinAugustenburger Platz 1BerlinBerlin13353Germany
| | - Ümit Hasirci
- Biofluid Mechanics LaboratoryInstitute for Imaging Science and Computational Modelling in Cardiovascular MedicineCharité – Universitätsmedizin BerlinAugustenburger Platz 1BerlinBerlin13353Germany
| | - Tim Rese
- Biofluid Mechanics LaboratoryInstitute for Imaging Science and Computational Modelling in Cardiovascular MedicineCharité – Universitätsmedizin BerlinAugustenburger Platz 1BerlinBerlin13353Germany
| | - Josef Seefeldt
- Institute of Fluid Dynamics and Technical AcousticsHermann‐Föttinger‐InstituteChair of Fluid DynamicsTU BerlinStraße des 17. Juni, 135BerlinBerlin10623Germany
| | - Sebastian Schimek
- Institute of Fluid Dynamics and Technical AcousticsHermann‐Föttinger‐InstituteChair of Fluid DynamicsTU BerlinStraße des 17. Juni, 135BerlinBerlin10623Germany
| | - Ulrich Kertzscher
- Biofluid Mechanics LaboratoryInstitute for Imaging Science and Computational Modelling in Cardiovascular MedicineCharité – Universitätsmedizin BerlinAugustenburger Platz 1BerlinBerlin13353Germany
| | - Christian Oliver Paschereit
- Institute of Fluid Dynamics and Technical AcousticsHermann‐Föttinger‐InstituteChair of Fluid DynamicsTU BerlinStraße des 17. Juni, 135BerlinBerlin10623Germany
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17
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Kollepara PK, Siegenfeld AF, Taleb NN, Bar-Yam Y. Unmasking the mask studies: why the effectiveness of surgical masks in preventing respiratory infections has been underestimated. J Travel Med 2021; 28:taab144. [PMID: 34490465 PMCID: PMC8499874 DOI: 10.1093/jtm/taab144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/27/2021] [Accepted: 08/31/2021] [Indexed: 11/14/2022]
Abstract
BACKGROUND Pre-pandemic empirical studies have produced mixed statistical results on the effectiveness of masks against respiratory viruses, leading to confusion that may have contributed to organizations such as the WHO and CDC initially not recommending that the general public wear masks during the coronavirus disease 2019 pandemic. METHODS A threshold-based dose-response curve framework is used to analyse the effects of interventions on infection probabilities for both single and repeated exposure events. Empirical studies on mask effectiveness are evaluated with a statistical power analysis that includes the effect of adherence to mask usage protocols. RESULTS When the adherence to mask usage guidelines is taken into account, the empirical evidence indicates that masks prevent disease transmission: all studies we analysed that did not find surgical masks to be effective were under-powered to such an extent that even if masks were 100% effective, the studies in question would still have been unlikely to find a statistically significant effect. We also provide a framework for understanding the effect of masks on the probability of infection for single and repeated exposures. The framework demonstrates that masks can have a disproportionately large protective effect and that more frequently wearing a mask provides super-linearly compounding protection. CONCLUSIONS This work shows (1) that both theoretical and empirical evidence is consistent with masks protecting against respiratory infections and (2) that non-linear effects and statistical considerations regarding the percentage of exposures for which masks are worn must be taken into account when designing empirical studies and interpreting their results.
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Affiliation(s)
- Pratyush K Kollepara
- New England Complex Systems Institute, Cambridge, MA, USA
- Department of Physics, BITS Pilani K K Birla Goa Campus, Goa, India
| | - Alexander F Siegenfeld
- New England Complex Systems Institute, Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Yaneer Bar-Yam
- New England Complex Systems Institute, Cambridge, MA, USA
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18
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Ereth MH, Fine J, Stamatatos F, Mathew B, Hess D, Simpser E. Healthcare-associated infection impact with bioaerosol treatment and COVID-19 mitigation measures. J Hosp Infect 2021; 116:69-77. [PMID: 34302883 PMCID: PMC8295046 DOI: 10.1016/j.jhin.2021.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 01/22/2023]
Abstract
BACKGROUND The real-world impact of breathing zone air purification and coronavirus disease 2019 (COVID-19) mitigation measures on healthcare-associated infections is not well documented. Engineering solutions to treat airborne transmission of disease may yield results in controlled test chambers or single rooms, but have not been reported on hospital-wide applications, and the impact of COVID-19 mitigation measures on healthcare-associated infection rates is unknown. AIM To determine the impact of hospital-wide bioaerosol treatment and COVID-19 mitigation measures on clinical outcomes. METHODS The impact of the step-wise addition of air disinfection technology and COVID-19 mitigation measures to standard multi-modal infection control on particle counts, viral and bacterial bioburden, and healthcare-associated infection rates was investigated in a 124-bed hospital (>100,000 patient-days over 30 months). FINDINGS AND CONCLUSION The addition of air disinfection technology and COVID-19 mitigation measures reduced airborne ultrafine particles, altered hospital bioburden, and reduced healthcare-associated infections from 11.9 to 6.6 (per 1000 patient-days) and from 6.6 to 1.0 (per 1000 patient-days), respectively (P<0.0001, R2=0.86). No single technology, tool or procedure will eliminate healthcare-associated infections, but the addition of a ubiquitous facility-wide engineering solution at limited expense and with no alteration to patient, visitor or staff traffic or workflow patterns reduced infections by 45%. A similar impact was documented with the addition of comprehensive, restrictive, and labour- and material-intensive COVID-19 mitigation measures. To the authors' knowledge, this is the first direct comparison between traditional infection control, an engineering solution and COVID-19 mitigation measures.
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Affiliation(s)
- M H Ereth
- Mayo Clinic College of Medicine, Rochester, MN, USA.
| | - J Fine
- St. Mary's Hospital for Children, Bayside, NY, USA
| | | | - B Mathew
- St. Mary's Hospital for Children, Bayside, NY, USA
| | - D Hess
- SecureAire, Inc, Dunedin, FL, USA
| | - E Simpser
- St. Mary's Hospital for Children, Bayside, NY, USA
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19
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Kasbe PS, Gade H, Liu S, Chase GG, Xu W. Ultrathin Polydopamine-Graphene Oxide Hybrid Coatings on Polymer Filters with Improved Filtration Performance and Functionalities. ACS APPLIED BIO MATERIALS 2021; 4:5180-5188. [PMID: 35007001 DOI: 10.1021/acsabm.1c00367] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Thin polymer fiber mats, in particular those made of nonwoven polypropylene (PP) fibers, are extensively used for medical and industrial filtration. The recent pandemic has increased the demand for the fabrication of protective masks. The nonwoven PP filter has limitations in filtration efficiency and lacks advanced functionalities. Here, we propose a simple, effective, and low-cost method to functionalize PP filters and endow antimicrobial and photothermal properties. Our approach is based on the deposition of an ultrathin hybrid coating composed of graphene oxide (GO) and polydopamine on the surface of PP filters by spray-coating. The complementary properties and synergic effects of GO and polydopamine in the ultrathin coating improved the filtration efficiency of the PP filter by 20% with little change in pressure drop. Single component coatings did not result in similar improvements in performance. The ultrathin coating also makes the surface of the filter more hydrophilic with negative charges. The photothermal property of GO enables a rapid temperature increase of the surface-coated filter upon light irradiation for easy sterilization. Furthermore, cationic polymer brushes can be grafted to the ultrathin hybrid coating, which adds the highly desired antimicrobial property to the PP filters for their more effective protection against microorganisms.
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Affiliation(s)
- Pratik S Kasbe
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Harshal Gade
- Department of Chemical, Biomolecular, and Corrosion Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Shan Liu
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - George G Chase
- Department of Chemical, Biomolecular, and Corrosion Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Weinan Xu
- School of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
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20
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Aerosols should not be defined by distance travelled. J Hosp Infect 2021; 115:131-132. [PMID: 34048848 PMCID: PMC8149158 DOI: 10.1016/j.jhin.2021.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 05/16/2021] [Indexed: 01/21/2023]
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21
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Lynch RM, Favata E, Gochfeld M. Assess Ventilation When Determining Safe Distancing in Schools to Control COVID-19 Transmission. Clin Infect Dis 2021; 73:e1404-e1405. [PMID: 33895816 PMCID: PMC8135657 DOI: 10.1093/cid/ciab353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
| | - Elissa Favata
- Environmental & Occupational Health Associates, Cherry Hill, NJ
| | - Michael Gochfeld
- Professor Emeritus, Rutgers Biomedical and Health Sciences, Environmental and Occupational Health Sciences Institute
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22
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August A, Bolhouse M, Rice B, Wall JK. Negative pressure patient isolation device to enable non-invasive respiratory support for COVID-19 and beyond. BMJ INNOVATIONS 2021; 7:292-296. [PMID: 37556246 PMCID: PMC7736963 DOI: 10.1136/bmjinnov-2020-000551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Auriel August
- General
Surgery, Stanford Medicine, Stanford, California, USA
- Biodesign,
Stanford University, Palo
Alto, California,
USA
| | | | - Brian Rice
- Emergency
Medicine, Stanford Medicine, Stanford, California, USA
| | - James Kennedy Wall
- Pediatric
Surgery, Stanford Children's Health,
Palo Alto, California, USA
- Bioengineering, Stanford University, Palo Alto, California, USA
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23
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Salimnia H, Meyer MP, Mitchell R, Fairfax MR, Gundel A, Guru N, Chopra T. A laboratory model demonstrating the protective effects of surgical masks, face shields, and a combination of both in a speaking simulation. Am J Infect Control 2021; 49:409-415. [PMID: 33485923 PMCID: PMC7826106 DOI: 10.1016/j.ajic.2021.01.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 11/19/2022]
Abstract
Background The protection against aerosol transmission provided by masks vs face shields or in combination when speaking indoors is not well understood. Methods To simulate a human source, an aerosol generating system was made using a bacterial suspension in a nebulizer attached to an oxygen cylinder. A fan connected to the nebulizer created aerosols. Transmitted aerosols were detected using blood agar plates at 0.1524 and 1.8288 meters from source, simulating exposed person. The study was performed under controlled conditions at room temperature in a biohazard hood with high-efficiency particulate air (HEPA) filter and UV light. Results When face shields were used alone, significant numbers of bacterial colonies grew on blood agar plates. When a mask used alone for both the subjects (source and exposed), the blood agar yielded minimal colony forming units at both distances. When face shields were used in combination with masks, no significant improvement was observed as compared to masks alone. Discussion Our results were similar to what have been observed in related studies. Conclusions Surgical masks alone provided good protection, surpassing the protection provided by face shields alone. Both used together provided the best protection, although the combined protection was similar to surgical masks use alone.
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Affiliation(s)
- Hossein Salimnia
- Detroit Medical Center, Microbiology Laboratory, Detroit, MI; Department of Pathology, Wayne State University School of Medicine, Detroit, MI
| | - Monica P Meyer
- Division of Infectious Diseases, Detroit Medical Center, Detroit, MI; Department of Internal Medicine, Wayne State University School of Medicine, MI
| | - Robert Mitchell
- Detroit Medical Center, Microbiology Laboratory, Detroit, MI
| | - Marilynn R Fairfax
- Detroit Medical Center, Microbiology Laboratory, Detroit, MI; Department of Pathology, Wayne State University School of Medicine, Detroit, MI
| | - Angela Gundel
- Detroit Medical Center, Microbiology Laboratory, Detroit, MI; Department of Pathology, Wayne State University School of Medicine, Detroit, MI
| | - Navneet Guru
- Department of Pathology, Wayne State University School of Medicine, Detroit, MI
| | - Teena Chopra
- Division of Infectious Diseases, Detroit Medical Center, Detroit, MI; Department of Internal Medicine, Wayne State University School of Medicine, MI.
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24
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Patel RB, Skaria SD, Mansour MM, Smaldone GC. Control de la fuente respiratoria mediante el uso de una mascarilla quirúrgica: un estudio in vitro. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2021; 18:S25-S34. [PMID: 33822697 DOI: 10.1080/15459624.2021.1877068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
RESUMENLa etiqueta para la tos y la higiene respiratoria son formas de control de la fuente de emisión cuyo uso se alienta para evitar la propagación de infecciones respiratorias. El uso de mascarillas quirúrgicas como medio de control de la fuente en términos de reducción de la exposición de terceros no se ha investigado. En este estudio diseñamos un modelo in vitro utilizando varias mascarillas faciales con el fin de evaluar su aporte a la reducción de la exposición cuando son utilizadas en la fuente infecciosa (Fuente) en comparación con la reducción proporcionada por las mascarillas usadas para la protección primaria (Receptor), así como los factores que contribuyen a cada una. En una cámara con diversos flujos de aire se exhalaron aerosoles radiomarcados desde una cabeza de maniquí de cara blanda ventilada, utilizando respiración periódica y tos (Fuente). En otro maniquí, al que se le colocó un filtro, se cuantificó la exposición del Receptor. Se probaron una mascarilla quirúrgica de ajuste natural, una mascarilla quirúrgica de ajuste seguro (SecureFit) y una mascarilla respiratoria autofiltrante de clase N95 (comúnmente conocida como "mascarilla autofiltrante N95") con y sin sello de vaselina. Con la tos, el control de la fuente (mascarilla quirúrgica/autofiltrante colocada en la Fuente) fue estadísticamente superior a la protección brindada por la mascarilla quirúrgica/mascarilla autofiltrante sin sellar en el Receptor (protección del Receptor) en todos los entornos. Para igualar el control de la fuente durante la tos, la mascarilla autofiltrante N95 debe estar sellada con vaselina. Durante la respiración periódica, el control de la fuente fue comparable o superior a la protección brindada por la mascarilla quirúrgica/autofiltrante en el Receptor. El control de la fuente mediante mascarillas quirúrgicas puede ser una importante defensa adicional contra la propagación de infecciones respiratorias. El ajuste de la mascarilla quirúrgica/autofiltrante combinado con los patrones de flujo de aire en un entorno determinado contribuye de manera significativa a la eficacia del control de la fuente. Los futuros ensayos clínicos deberían incluir un brazo de control de la fuente con mascarilla quirúrgica a fin de evaluar el aporte realizado por el control de la fuente a la protección general contra infecciones de transmisión aérea.
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Affiliation(s)
- Rajeev B Patel
- Centro Médico Universitario Stony Brook, Medicina Pulmonar, deSk Cuidados Críticos y del Sueño, Stony Brook, Nueva York
| | - Shaji D Skaria
- Centro Médico Universitario Stony Brook, Medicina Pulmonar, deSk Cuidados Críticos y del Sueño, Stony Brook, Nueva York
| | - Mohamed M Mansour
- Centro Médico Universitario Stony Brook, Medicina Pulmonar, deSk Cuidados Críticos y del Sueño, Stony Brook, Nueva York
| | - Gerald C Smaldone
- Centro Médico Universitario Stony Brook, Medicina Pulmonar, deSk Cuidados Críticos y del Sueño, Stony Brook, Nueva York
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Lukanina KI, Budyka AK, Rebrov IE, Antipova KG, Malakhov SN, Shepelev AD, Grigoriev TE, Yamshchikov VA, Chvalun SN. Efficiency of Respiratory Protective Equipment in the SARS-CoV-2 Pandemic. NANOBIOTECHNOLOGY REPORTS 2021. [PMCID: PMC8241409 DOI: 10.1134/s2635167621010080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- K. I. Lukanina
- National Research Center Kurchatov Institute, 123182 Moscow, Russia
| | - A. K. Budyka
- National Research Nuclear University MEPhI, 115409 Moscow, Russia
| | - I. E. Rebrov
- Institute of Electrophysics and Electric Power, Russian Academy of Sciences, 191186 St. Petersburg, Russia
| | - K. G. Antipova
- National Research Center Kurchatov Institute, 123182 Moscow, Russia
| | - S. N. Malakhov
- National Research Center Kurchatov Institute, 123182 Moscow, Russia
| | - A. D. Shepelev
- National Research Center Kurchatov Institute, 123182 Moscow, Russia
| | - T. E. Grigoriev
- National Research Center Kurchatov Institute, 123182 Moscow, Russia
| | - V. A. Yamshchikov
- Institute of Electrophysics and Electric Power, Russian Academy of Sciences, 191186 St. Petersburg, Russia
| | - S. N. Chvalun
- National Research Center Kurchatov Institute, 123182 Moscow, Russia
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26
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Ghaly R, Perciuleac Z, Pleasca A, Pirvulescu I, Candido KD, Knezevic NN. Innovative overhead transparent plastic barrier with powered suction technique intended to limit coronavirus disease 2019 aerosols spread during fiber-optic intubation and throughout the surgery. Surg Neurol Int 2020; 11:473. [PMID: 33500811 PMCID: PMC7827365 DOI: 10.25259/sni_801_2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/11/2020] [Indexed: 01/25/2023] Open
Abstract
Background: In the context of the current coronavirus pandemic, we propose an inexpensive, innovative overhead transparent plastic barrier with powered suction (OTPBPS) technique using materials that are ubiquitous in the hospital, easy to set up in minutes and well tolerated by the patients. As presented in this case report, it is an effective method to reduce viral spread from patients with positive or suspected yet unconfirmed coronavirus disease 2019 status. Case Description: A 49-year-old male was admitted to the hospital with a diagnosis of cervical stenosis and a C6-C7 disc herniation with spinal cord compression. The OTPBPS technique was set up to create a negative pressure environment around the patient’s head, using a Mayo stand, a transparent plastic bag, and powered wall canister suction. The neurosurgeon successfully performed an anterior cervical discectomy and instrumented fusion under OTPBPS. The patient was satisfied with the intubation and anesthetic management and reported excellent feedback. Conclusion: The OTPBPS technique helps control the spread of an aerosolized viral load from the patient’s mouth or airway during awake fiber-optic intubation. This technique will help anesthesiologists and other front-line health-care providers manage copious endotracheal secretions and droplet particles, which have an immense infectious potential.
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Affiliation(s)
- Ramsis Ghaly
- Department of Anesthesiology, University of Chicago at Illinois, Advocate Illinois Masonic Medical Center, Chicago, Illinois, United States
| | - Zinaida Perciuleac
- Department of Anesthesiology, University of Chicago at Illinois, Advocate Illinois Masonic Medical Center, Chicago, Illinois, United States
| | - Ana Pleasca
- Department of Anesthesiology, University of Chicago at Illinois, Advocate Illinois Masonic Medical Center, Chicago, Illinois, United States
| | - Iulia Pirvulescu
- Department of Anesthesiology, University of Chicago at Illinois, Advocate Illinois Masonic Medical Center, Chicago, Illinois, United States
| | - Kenneth D Candido
- Department of Anesthesiology, University of Chicago at Illinois, Advocate Illinois Masonic Medical Center, Chicago, Illinois, United States
| | - Nebojsa Nick Knezevic
- Department of Anesthesiology, University of Chicago at Illinois, Advocate Illinois Masonic Medical Center, Chicago, Illinois, United States
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27
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Arumuru V, Pasa J, Samantaray SS. Experimental visualization of sneezing and efficacy of face masks and shields. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2020; 32:115129. [PMID: 33244217 PMCID: PMC7684680 DOI: 10.1063/5.0030101] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/01/2020] [Indexed: 05/02/2023]
Abstract
In the present work, we propose and demonstrate a simple experimental visualization to simulate sneezing by maintaining dynamic similarity to actual sneezing. A pulsed jet with Reynolds number Re = 30 000 is created using compressed air and a solenoid valve. Tracer particles are introduced in the flow to capture the emulated turbulent jet formed due to a sneeze. The visualization is accomplished using a camera and laser illumination. It is observed that a typical sneeze can travel up to 25 ft in ∼22 s in a quiescent environment. This highlights that the present widely accepted safe distance of 6 ft is highly underestimated, especially under the act of a sneeze. Our study demonstrates that a three-layer homemade mask is just adequate to impede the penetration of fine-sized particles, which may cause the spreading of the infectious pathogen responsible for COVID-19. However, a surgical mask cannot block the sneeze, and the sneeze particle can travel up to 2.5 ft. We strongly recommend using at least a three-layer homemade mask with a social distancing of 6 ft to combat the transmission of COVID-19 virus. In offices, we recommend the use of face masks and shields to prevent the spreading of droplets carrying the infectious pathogen. Interestingly, an N-95 mask blocks the sneeze in the forward direction; however, the leakage from the sides and top spreads the sneeze in the backward direction up to 2 ft. We strongly recommend using the elbow or hands to prevent droplet leakage even after wearing a mask during sneezing and coughing.
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Affiliation(s)
- Venugopal Arumuru
- Applied Fluids Group, School of Mechanical Sciences, Indian Institute of
Technology Bhubaneswar, Bhubaneswar 752050, India
| | - Jangyadatta Pasa
- Applied Fluids Group, School of Mechanical Sciences, Indian Institute of
Technology Bhubaneswar, Bhubaneswar 752050, India
| | - Sidhartha Sankar Samantaray
- Applied Fluids Group, School of Mechanical Sciences, Indian Institute of
Technology Bhubaneswar, Bhubaneswar 752050, India
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Samaranayake LP, Fakhruddin KS, Ngo HC, Chang JWW, Panduwawala C. The effectiveness and efficacy of respiratory protective equipment (RPE) in dentistry and other health care settings: a systematic review. Acta Odontol Scand 2020; 78:626-639. [PMID: 32881590 DOI: 10.1080/00016357.2020.1810769] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE The global pandemic of coronavirus disease-19, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is the latest hazard facing healthcare workers (HCW) including dental care workers (DCW). It is clear that the major mode of SARS-CoV-2 transmission is the airborne route, through inhalation of virus-infested aerosols and droplets. Several respiratory protection equipment (RPE), including masks, face shields/visors, and respirators, are available to obviate facial and conjunctival contamination by microbes. However, as their barrier value against microbial inhalation has not been evaluated, we systematically reviewed the data on the effectiveness and efficacy of facemasks and respirators, including protective eyewear, with particular emphasis on dental healthcare. MATERIAL AND METHODS PubMed, MEDLINE, the Cochrane Library, and Embase databases were searched between 01January 1990 and 15 May 2020. RESULTS Of 310 identified English language records, 21 were included as per eligibility criteria. In clinical terms, wearing layered, face-fitting masks/respirators and protective-eyewear can limit the spread of infection among HCWs. Specifically, combined interventions such as a face mask and a face shield, better resist bioaerosol inhalation than either alone. The prolonged and over-extended use of surgical masks compromise their effectiveness. CONCLUSIONS In general, RPE is effective as a barrier protection against aerosolized microbes in healthcare settings. But their filtration efficacy is compromised by the (i) inhalant particle size, (ii) airflow dynamics, (iii) mask-fit factor, (iv) period of wear, (v) 'wetness' of the masks, and (vi) their fabrication quality. The macro-data presented here should inform policy formulation on RPE wear amongst HCWs.
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Affiliation(s)
| | | | - Hien Chi Ngo
- School of Dentistry, University of Western Australia, Perth, Australia
| | - Jeffrey Wen Wei Chang
- Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Chamila Panduwawala
- Department of Preventive and Restorative Dentistry, University of Sharjah, Sharjah, UAE
- Department Oral and Craniofacial Health Sciences, University of Sharjah, Sharjah, UAE
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29
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Timmons Sund L, Bhatt NK, Ference EH, Kim W, Johns MM. Respiratory Particle Emission During Voice Assessment and Therapy Tasks in a Single Subject. J Voice 2020; 36:784-792. [PMID: 33268220 PMCID: PMC7582043 DOI: 10.1016/j.jvoice.2020.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 01/20/2023]
Abstract
Introduction SARS-CoV-2 is transmitted via respiratory particles. Respiratory particle emission is impacted by manner of breathing and voicing, as well as intersubject variability. Assessment and treatment of voice disorders may include tasks that increase respiratory particle emission beyond typical breathing and speaking. This could increase the risk of disease transmission via respiratory particles. Methods Respiratory particle emission was measured during a single-subject, repeated measures clinical simulation of acoustic and aerodynamic assessment and voice therapy tasks. An optical particle sizer was used to measure particle count (1–10 μm in diameter). Assessment and therapy tasks were completed in three conditions: (1) 15 cm from the device, (2) 1 m from the device, and (3) 1 m from the device with the subject wearing a surgical mask. Results Condition 1 generated the highest particle count, with a median of 5.1 (13) additional particles above baseline, which was statistically significant (U = 381.5, P= 0.002). In condition 1, therapy and acoustic tasks combined produced more particles compared to the baseline and speech tasks, with a median difference of 6.5 additional particles per time point (U = 309.0, P= 0.002). This difference was not significant for conditions 2 and 3. Peak particle generation occurred in specific phonatory tasks, which was most pronounced in condition 1. Voice therapy tasks during condition 1 generated the highest peaks of normalized total particles with classical singing and expiratory muscle strength training. There was a significant difference in the amount of particle generation between condition 1 and 2, with a median difference of 5.2 particles (U = 461.0, P= 0.002). The particle count difference between conditions 2 and 3 was 2.1 (U = 282.0, P= 0.292), and this difference was not significant. The normalized total particles were assessed over time for each condition. For all conditions, there was no significant accumulation of particles. Conclusions For a single subject, production of voice assessment and therapy tasks combined resulted in an increased number of respiratory particles compared to speech and baseline (1–10 μm). EMST and classical singing generated the greatest concentration of particles. Respiratory particle counts were higher at 15 cm from the particle sizer compared to 1 m from the particle sizer, suggesting that physical distancing may reduce immediate clinician exposure to respiratory particles. Particle concentration did not accumulate over time.
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Affiliation(s)
- Lauren Timmons Sund
- USC Voice Center, USC Caruso Department of Otolaryngology - Head and Neck Surgery at Keck Medicine of USC, University of Southern California, Los Angeles, California
| | - Neel K Bhatt
- USC Voice Center, USC Caruso Department of Otolaryngology - Head and Neck Surgery at Keck Medicine of USC, University of Southern California, Los Angeles, California
| | - Elisabeth H Ference
- USC Caruso Department of Otolaryngology - Head and Neck Surgery at Keck Medicine of USC, University of Southern California, Los Angeles, California
| | - Wihan Kim
- USC Caruso Department of Otolaryngology - Head and Neck Surgery at Keck Medicine of USC, University of Southern California, Los Angeles, California
| | - Michael M Johns
- USC Voice Center, USC Caruso Department of Otolaryngology - Head and Neck Surgery at Keck Medicine of USC, University of Southern California, Los Angeles, California.
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30
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Jackson T, Deibert D, Wyatt G, Durand-Moreau Q, Adisesh A, Khunti K, Khunti S, Smith S, Chan XHS, Ross L, Roberts N, Toomey E, Greenhalgh T, Arora I, Black SM, Drake J, Syam N, Temple R, Straube S. Classification of aerosol-generating procedures: a rapid systematic review. BMJ Open Respir Res 2020; 7:e000730. [PMID: 33040021 PMCID: PMC7549490 DOI: 10.1136/bmjresp-2020-000730] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 08/15/2020] [Indexed: 12/30/2022] Open
Abstract
In the context of covid-19, aerosol generating procedures have been highlighted as requiring a higher grade of personal protective equipment. We investigated how official guidance documents and academic publications have classified procedures in terms of whether or not they are aerosol-generating. We performed a rapid systematic review using preferred reporting items for systematic reviews and meta-analyses standards. Guidelines, policy documents and academic papers published in english or french offering guidance on aerosol-generating procedures were eligible. We systematically searched two medical databases (medline, cochrane central) and one public search engine (google) in march and april 2020. Data on how each procedure was classified by each source were extracted. We determined the level of agreement across different guidelines for each procedure group, in terms of its classification as aerosol generating, possibly aerosol-generating, or nonaerosol-generating. 128 documents met our inclusion criteria; they contained 1248 mentions of procedures that we categorised into 39 procedure groups. Procedures classified as aerosol-generating or possibly aerosol-generating by ≥90% of documents included autopsy, surgery/postmortem procedures with high-speed devices, intubation and extubation procedures, bronchoscopy, sputum induction, manual ventilation, airway suctioning, cardiopulmonary resuscitation, tracheostomy and tracheostomy procedures, non-invasive ventilation, high-flow oxygen therapy, breaking closed ventilation systems, nebulised or aerosol therapy, and high frequency oscillatory ventilation. Disagreements existed between sources on some procedure groups, including oral and dental procedures, upper gastrointestinal endoscopy, thoracic surgery and procedures, and nasopharyngeal and oropharyngeal swabbing. There is sufficient evidence of agreement across different international guidelines to classify certain procedure groups as aerosol generating. However, some clinically relevant procedures received surprisingly little mention in our source documents. To reduce dissent on the remainder, we recommend that (a) clinicians define procedures more clearly and specifically, breaking them down into their constituent components where possible; (b) researchers undertake further studies of aerosolisation during these procedures; and (c) guideline-making and policy-making bodies address a wider range of procedures.
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Affiliation(s)
- Tanya Jackson
- Division of Preventive Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Danika Deibert
- Division of Preventive Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Graeme Wyatt
- Division of Preventive Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Quentin Durand-Moreau
- Division of Preventive Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Anil Adisesh
- Division of Occupational Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Kamlesh Khunti
- Diabetes Research Centre, University of Leicester, Leicester, UK
| | - Sachin Khunti
- School of Medicine and Dentistry, Barts and the London School of Medicine and Dentistry, London, UK
| | - Simon Smith
- Canadian Standards Biological Aerosols Group, Canadian Standards Association, Toronto, Ontario, Canada
| | - Xin Hui S Chan
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, Oxfordshire, UK
| | - Lawrence Ross
- Division of Infectious Diseases, Children's Hospital of Los Angeles, Los Angeles, California, USA
| | - Nia Roberts
- Bodleian Health Care Libraries, University of Oxford, Oxford, Oxfordshire, UK
| | - Elaine Toomey
- School of Allied Health, University of Limerick, Limerick, Ireland
| | - Trisha Greenhalgh
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, Oxfordshire, UK
| | - Isheeta Arora
- Medical Sciences Division, University of Oxford, Oxford, Oxfordshire, UK
| | - Susannah M Black
- Medical Sciences Division, University of Oxford, Oxford, Oxfordshire, UK
| | - Jonathan Drake
- Medical Sciences Division, University of Oxford, Oxford, Oxfordshire, UK
| | - Nandana Syam
- Medical Sciences Division, University of Oxford, Oxford, Oxfordshire, UK
| | - Robert Temple
- Medical Sciences Division, University of Oxford, Oxford, Oxfordshire, UK
| | - Sebastian Straube
- Division of Preventive Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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31
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Schutzer-Weissmann J, Magee DJ, Farquhar-Smith P. Severe acute respiratory syndrome coronavirus 2 infection risk during elective peri-operative care: a narrative review. Anaesthesia 2020; 75:1648-1658. [PMID: 32652529 PMCID: PMC7404908 DOI: 10.1111/anae.15221] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2020] [Indexed: 12/11/2022]
Abstract
The protection of healthcare workers from the risk of nosocomial severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection is a paramount concern. SARS‐CoV‐2 is likely to remain endemic and measures to protect healthcare workers against nosocomial infection will need to be maintained. This review aims to inform the assessment and management of the risk of SARS‐CoV‐2 transmission to healthcare workers involved in elective peri‐operative care. In the absence of data specifically related to the risk of SARS‐CoV‐2 transmission in the peri‐operative setting, we explore the evidence‐base that exists regarding modes of viral transmission, historical evidence for the risk associated with aerosol‐generating procedures and contemporaneous data from the COVID‐19 pandemic. We identify a significant lack of data regarding the risk of transmission in the management of elective surgical patients, highlighting the urgent need for further research.
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Affiliation(s)
- J Schutzer-Weissmann
- Department of Anaesthesia, Peri-operative Medicine, Pain and Critical Care, Royal Marsden Hospital NHS Foundation Trust, London, UK
| | - D J Magee
- Imperial School of Anaesthesia, London, UK.,The Institute of Cancer Research, London, UK
| | - P Farquhar-Smith
- Department of Anaesthesia, Peri-operative Medicine, Pain and Critical Care, Royal Marsden Hospital NHS Foundation Trust, London, UK
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Abstract
La connaissance des modes de transmission du SARS-CoV-2 est un élément fondamental dans l’élaboration des stratégies de prévention en santé au travail et en santé publique dans le cadre de la gestion de crise du Covid-19. Le SARS-CoV-2 est retrouvé dans les voies aériennes des patients, y compris asymptomatiques. Les données récentes de la littérature suggèrent un risque de transmission du SARS-CoV-2 par voie aérienne qui a probablement été sous-estimé, notamment via des aérosols générés par la toux ou les éternuements, mais aussi plus simplement la parole et la respiration, et donc la composition est majoritairement le fait de particules dont le diamètre est inférieur ou égal à 1 μm. Des données préliminaires montrent la présence d’ARN viral dans l’air et sur des surfaces distantes des patients sources. Cependant, il est important de noter que la détection de matériel génétique viral par RT-PCR ne signifie pas que le virus soit vivant et infectant. En fonction de données sur la quantification du pouvoir infectant des aérosols de petite taille et si l’hypothèse d’une telle transmission était confirmée, les indications de port des protections respiratoires de type FFP2 mériteraient d’être élargies, notamment en milieu de soin.
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33
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Zhao M, Liao L, Xiao W, Yu X, Wang H, Wang Q, Lin YL, Kilinc-Balci FS, Price A, Chu L, Chu MC, Chu S, Cui Y. Household Materials Selection for Homemade Cloth Face Coverings and Their Filtration Efficiency Enhancement with Triboelectric Charging. NANO LETTERS 2020; 20:5544-5552. [PMID: 32484683 PMCID: PMC10760933 DOI: 10.1021/acs.nanolett.0c02211] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/01/2020] [Indexed: 05/17/2023]
Abstract
The COVID-19 pandemic is currently causing a severe disruption and shortage in the global supply chain of necessary personal protective equipment (e.g., N95 respirators). The U.S. CDC has recommended use of household cloth by the general public to make cloth face coverings as a method of source control. We evaluated the filtration properties of natural and synthetic materials using a modified procedure for N95 respirator approval. Common fabrics of cotton, polyester, nylon, and silk had filtration efficiency of 5-25%, polypropylene spunbond had filtration efficiency 6-10%, and paper-based products had filtration efficiency of 10-20%. An advantage of polypropylene spunbond is that it can be simply triboelectrically charged to enhance the filtration efficiency (from 6 to >10%) without any increase in pressure (stable overnight and in humid environments). Using the filtration quality factor, fabric microstructure, and charging ability, we are able to provide an assessment of suggested fabric materials for homemade facial coverings.
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Affiliation(s)
- Mervin Zhao
- 4C Air, Inc., Sunnyvale, California 94089, United States
| | - Lei Liao
- 4C Air, Inc., Sunnyvale, California 94089, United States
| | - Wang Xiao
- 4C Air, Inc., Sunnyvale, California 94089, United States
| | - Xuanze Yu
- 4C Air, Inc., Sunnyvale, California 94089, United States
| | - Haotian Wang
- 4C Air, Inc., Sunnyvale, California 94089, United States
| | - Qiqi Wang
- 4C Air, Inc., Sunnyvale, California 94089, United States
| | - Ying Ling Lin
- World Health Organization, Geneva, CH-1211, Switzerland
| | - F Selcen Kilinc-Balci
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, Washington, DC 20201, United States
| | - Amy Price
- Stanford Anesthesia Informatics and Media (AIM) Lab, Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Larry Chu
- Stanford Anesthesia Informatics and Media (AIM) Lab, Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, California 94305, United States
| | - May C Chu
- Colorado School of Public Health, University of Colorado, Aurora, Colorado 80045, United States
| | - Steven Chu
- Department of Physics, Stanford University, Stanford, California 94305, United States
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Yi Cui
- Department of Materials Science and Engineering, Stanford University, Stanford California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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34
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Kohanski MA, Palmer JN, Cohen NA. Aerosol or droplet: critical definitions in the COVID-19 era. Int Forum Allergy Rhinol 2020; 10:968-969. [PMID: 32323923 PMCID: PMC7264789 DOI: 10.1002/alr.22591] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 04/18/2020] [Accepted: 04/21/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Michael A Kohanski
- Department of Otorhinolaryngology-Head and Neck Surgery, Division of Rhinology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - James N Palmer
- Department of Otorhinolaryngology-Head and Neck Surgery, Division of Rhinology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA
| | - Noam A Cohen
- Department of Otorhinolaryngology-Head and Neck Surgery, Division of Rhinology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA.,Philadelphia Veterans Affairs Medical Center, Philadelphia, PA.,Monell Chemical Senses Center, Philadelphia, PA
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35
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Iannone P, Castellini G, Coclite D, Napoletano A, Fauci AJ, Iacorossi L, D’Angelo D, Renzi C, La Torre G, Mastroianni CM, Gianola S. The need of health policy perspective to protect Healthcare Workers during COVID-19 pandemic. A GRADE rapid review on the N95 respirators effectiveness. PLoS One 2020; 15:e0234025. [PMID: 32492045 PMCID: PMC7269249 DOI: 10.1371/journal.pone.0234025] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/18/2020] [Indexed: 01/22/2023] Open
Abstract
Protecting Health Care Workers (HCWs) during routine care of suspected or confirmed COVID-19 patients is of paramount importance to halt the SARS-CoV-2 (Severe Acute Respiratory Syndrome-Coronavirus-2) pandemic. The WHO, ECDC and CDC have issued conflicting guidelines on the use of respiratory filters (N95) by HCWs. We searched PubMed, Embase and The Cochrane Library from the inception to March 21, 2020 to identify randomized controlled trials (RCTs) comparing N95 respirators versus surgical masks for prevention of COVID-19 or any other respiratory infection among HCWs. The grading of recommendations, assessment, development, and evaluation (GRADE) was used to evaluate the quality of evidence. Four RCTs involving 8736 HCWs were included. We did not find any trial specifically on prevention of COVID-19. However, wearing N95 respirators can prevent 73 more (95% CI 46-91) clinical respiratory infections per 1000 HCWs compared to surgical masks (2 RCTs; 2594 patients; low quality of evidence). A protective effect of N95 respirators in laboratory-confirmed bacterial colonization (RR = 0.41; 95%CI 0.28-0.61) was also found. A trend in favour of N95 respirators was observed in preventing laboratory-confirmed respiratory viral infections, laboratory-confirmed respiratory infection, and influenza like illness. We found no direct high quality evidence on whether N95 respirators are better than surgical masks for HCWs protection from SARS-CoV-2. However, low quality evidence suggests that N95 respirators protect HCWs from clinical respiratory infections. This finding should be contemplated to decide the best strategy to support the resilience of healthcare systems facing the potentially catastrophic SARS-CoV-2 pandemic.
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Affiliation(s)
- Primiano Iannone
- Centro Eccellenza Clinica, Qualità e Sicurezza delle Cure, Istituto Superiore di Sanità, Rome, Italy
| | - Greta Castellini
- Unit of Clinical Epidemiology, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Daniela Coclite
- Centro Eccellenza Clinica, Qualità e Sicurezza delle Cure, Istituto Superiore di Sanità, Rome, Italy
| | - Antonello Napoletano
- Centro Eccellenza Clinica, Qualità e Sicurezza delle Cure, Istituto Superiore di Sanità, Rome, Italy
| | - Alice Josephine Fauci
- Centro Eccellenza Clinica, Qualità e Sicurezza delle Cure, Istituto Superiore di Sanità, Rome, Italy
| | - Laura Iacorossi
- Centro Eccellenza Clinica, Qualità e Sicurezza delle Cure, Istituto Superiore di Sanità, Rome, Italy
| | - Daniela D’Angelo
- Centro Eccellenza Clinica, Qualità e Sicurezza delle Cure, Istituto Superiore di Sanità, Rome, Italy
| | - Cristina Renzi
- Institute of Epidemiology & Health Care, University College London-UCL, London, United Kingdom
| | - Giuseppe La Torre
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Claudio M. Mastroianni
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Silvia Gianola
- Unit of Clinical Epidemiology, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
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Verma S, Dhanak M, Frankenfield J. Visualizing the effectiveness of face masks in obstructing respiratory jets. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2020; 32:061708. [PMID: 32624649 PMCID: PMC7327717 DOI: 10.1063/5.0016018] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The use of face masks in public settings has been widely recommended by public health officials during the current COVID-19 pandemic. The masks help mitigate the risk of cross-infection via respiratory droplets; however, there are no specific guidelines on mask materials and designs that are most effective in minimizing droplet dispersal. While there have been prior studies on the performance of medical-grade masks, there are insufficient data on cloth-based coverings, which are being used by a vast majority of the general public. We use qualitative visualizations of emulated coughs and sneezes to examine how material- and design-choices impact the extent to which droplet-laden respiratory jets are blocked. Loosely folded face masks and bandana-style coverings provide minimal stopping-capability for the smallest aerosolized respiratory droplets. Well-fitted homemade masks with multiple layers of quilting fabric, and off-the-shelf cone style masks, proved to be the most effective in reducing droplet dispersal. These masks were able to curtail the speed and range of the respiratory jets significantly, albeit with some leakage through the mask material and from small gaps along the edges. Importantly, uncovered emulated coughs were able to travel notably farther than the currently recommended 6-ft distancing guideline. We outline the procedure for setting up simple visualization experiments using easily available materials, which may help healthcare professionals, medical researchers, and manufacturers in assessing the effectiveness of face masks and other personal protective equipment qualitatively.
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Affiliation(s)
- Siddhartha Verma
- Also at: Harbor Branch Oceanographic Institute, Florida
Atlantic University, Fort Pierce, FL 34946, USA. Author to whom correspondence should be
addressed: . URL: http://www.computation.fau.edu
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Thomas JP, Srinivasan A, Wickramarachchi CS, Dhesi PK, Hung YM, Kamath AV. Evaluating the national PPE guidance for NHS healthcare workers during the COVID-19 pandemic. Clin Med (Lond) 2020; 20:242-247. [PMID: 32357976 PMCID: PMC7354042 DOI: 10.7861/clinmed.2020-0143] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Tragically, many of the infections and deaths recorded in the global coronavirus disease 2019 (COVID-19) pandemic have occurred in healthcare workers. Some have attributed this to inadequate provision of personal protective equipment (PPE). In the UK, several organisations have voiced their concerns that the national PPE guidance issued by Public Health England is inadequate. Despite recent revisions to these guidelines, concerns remain that they offer insufficient protection to frontline NHS healthcare workers. In this report, we evaluate whether these concerns are merited, through critical appraisal of the available evidence, review of international PPE guidance, and consideration of the ethical implications.
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Affiliation(s)
- John P Thomas
- Norfolk and Norwich University Hospital, Norwich, UK
| | | | | | | | - Yat Ma Hung
- Norfolk and Norwich University Hospital, Norwich, UK
| | - Ajay V Kamath
- Norfolk and Norwich University Hospital, Norwich, UK
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Verbeek JH, Rajamaki B, Ijaz S, Sauni R, Toomey E, Blackwood B, Tikka C, Ruotsalainen JH, Kilinc Balci FS. Personal protective equipment for preventing highly infectious diseases due to exposure to contaminated body fluids in healthcare staff. Cochrane Database Syst Rev 2020; 5:CD011621. [PMID: 32412096 PMCID: PMC8785899 DOI: 10.1002/14651858.cd011621.pub5] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND In epidemics of highly infectious diseases, such as Ebola, severe acute respiratory syndrome (SARS), or coronavirus (COVID-19), healthcare workers (HCW) are at much greater risk of infection than the general population, due to their contact with patients' contaminated body fluids. Personal protective equipment (PPE) can reduce the risk by covering exposed body parts. It is unclear which type of PPE protects best, what is the best way to put PPE on (i.e. donning) or to remove PPE (i.e. doffing), and how to train HCWs to use PPE as instructed. OBJECTIVES To evaluate which type of full-body PPE and which method of donning or doffing PPE have the least risk of contamination or infection for HCW, and which training methods increase compliance with PPE protocols. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase and CINAHL to 20 March 2020. SELECTION CRITERIA We included all controlled studies that evaluated the effect of full-body PPE used by HCW exposed to highly infectious diseases, on the risk of infection, contamination, or noncompliance with protocols. We also included studies that compared the effect of various ways of donning or doffing PPE, and the effects of training on the same outcomes. DATA COLLECTION AND ANALYSIS Two review authors independently selected studies, extracted data and assessed the risk of bias in included trials. We conducted random-effects meta-analyses were appropriate. MAIN RESULTS Earlier versions of this review were published in 2016 and 2019. In this update, we included 24 studies with 2278 participants, of which 14 were randomised controlled trials (RCT), one was a quasi-RCT and nine had a non-randomised design. Eight studies compared types of PPE. Six studies evaluated adapted PPE. Eight studies compared donning and doffing processes and three studies evaluated types of training. Eighteen studies used simulated exposure with fluorescent markers or harmless microbes. In simulation studies, median contamination rates were 25% for the intervention and 67% for the control groups. Evidence for all outcomes is of very low certainty unless otherwise stated because it is based on one or two studies, the indirectness of the evidence in simulation studies and because of risk of bias. Types of PPE The use of a powered, air-purifying respirator with coverall may protect against the risk of contamination better than a N95 mask and gown (risk ratio (RR) 0.27, 95% confidence interval (CI) 0.17 to 0.43) but was more difficult to don (non-compliance: RR 7.5, 95% CI 1.81 to 31.1). In one RCT (59 participants) coveralls were more difficult to doff than isolation gowns (very low-certainty evidence). Gowns may protect better against contamination than aprons (small patches: mean difference (MD) -10.28, 95% CI -14.77 to -5.79). PPE made of more breathable material may lead to a similar number of spots on the trunk (MD 1.60, 95% CI -0.15 to 3.35) compared to more water-repellent material but may have greater user satisfaction (MD -0.46, 95% CI -0.84 to -0.08, scale of 1 to 5). According to three studies that tested more recently introduced full-body PPE ensembles, there may be no difference in contamination. Modified PPE versus standard PPE The following modifications to PPE design may lead to less contamination compared to standard PPE: sealed gown and glove combination (RR 0.27, 95% CI 0.09 to 0.78), a better fitting gown around the neck, wrists and hands (RR 0.08, 95% CI 0.01 to 0.55), a better cover of the gown-wrist interface (RR 0.45, 95% CI 0.26 to 0.78, low-certainty evidence), added tabs to grab to facilitate doffing of masks (RR 0.33, 95% CI 0.14 to 0.80) or gloves (RR 0.22, 95% CI 0.15 to 0.31). Donning and doffing Using Centers for Disease Control and Prevention (CDC) recommendations for doffing may lead to less contamination compared to no guidance (small patches: MD -5.44, 95% CI -7.43 to -3.45). One-step removal of gloves and gown may lead to less bacterial contamination (RR 0.20, 95% CI 0.05 to 0.77) but not to less fluorescent contamination (RR 0.98, 95% CI 0.75 to 1.28) than separate removal. Double-gloving may lead to less viral or bacterial contamination compared to single gloving (RR 0.34, 95% CI 0.17 to 0.66) but not to less fluorescent contamination (RR 0.98, 95% CI 0.75 to 1.28). Additional spoken instruction may lead to fewer errors in doffing (MD -0.9, 95% CI -1.4 to -0.4) and to fewer contamination spots (MD -5, 95% CI -8.08 to -1.92). Extra sanitation of gloves before doffing with quaternary ammonium or bleach may decrease contamination, but not alcohol-based hand rub. Training The use of additional computer simulation may lead to fewer errors in doffing (MD -1.2, 95% CI -1.6 to -0.7). A video lecture on donning PPE may lead to better skills scores (MD 30.70, 95% CI 20.14 to 41.26) than a traditional lecture. Face-to-face instruction may reduce noncompliance with doffing guidance more (odds ratio 0.45, 95% CI 0.21 to 0.98) than providing folders or videos only. AUTHORS' CONCLUSIONS We found low- to very low-certainty evidence that covering more parts of the body leads to better protection but usually comes at the cost of more difficult donning or doffing and less user comfort. More breathable types of PPE may lead to similar contamination but may have greater user satisfaction. Modifications to PPE design, such as tabs to grab, may decrease the risk of contamination. For donning and doffing procedures, following CDC doffing guidance, a one-step glove and gown removal, double-gloving, spoken instructions during doffing, and using glove disinfection may reduce contamination and increase compliance. Face-to-face training in PPE use may reduce errors more than folder-based training. We still need RCTs of training with long-term follow-up. We need simulation studies with more participants to find out which combinations of PPE and which doffing procedure protects best. Consensus on simulation of exposure and assessment of outcome is urgently needed. We also need more real-life evidence. Therefore, the use of PPE of HCW exposed to highly infectious diseases should be registered and the HCW should be prospectively followed for their risk of infection.
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Affiliation(s)
- Jos H Verbeek
- Cochrane Work Review Group, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Blair Rajamaki
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Sharea Ijaz
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | | | | | - Bronagh Blackwood
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Christina Tikka
- Finnish Institute of Occupational Health, TYÖTERVEYSLAITOS, Finland
| | | | - F Selcen Kilinc Balci
- National Personal Protective Technology Laboratory (NPPTL), National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Pittsburgh, PA, USA
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Efficacy of slit lamp breath shields. Eye (Lond) 2020; 34:1185-1186. [PMID: 32398843 PMCID: PMC7216572 DOI: 10.1038/s41433-020-0940-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 04/24/2020] [Accepted: 04/28/2020] [Indexed: 01/28/2023] Open
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Garcia Godoy LR, Jones AE, Anderson TN, Fisher CL, Seeley KML, Beeson EA, Zane HK, Peterson JW, Sullivan PD. Facial protection for healthcare workers during pandemics: a scoping review. BMJ Glob Health 2020; 5:bmjgh-2020-002553. [PMID: 32371574 PMCID: PMC7228486 DOI: 10.1136/bmjgh-2020-002553] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 11/04/2022] Open
Abstract
Background The coronavirus disease 2019 (COVID-19) pandemic has led to personal protective equipment (PPE) shortages, requiring mask reuse or improvisation. We provide a review of medical-grade facial protection (surgical masks, N95 respirators and face shields) for healthcare workers, the safety and efficacy of decontamination methods, and the utility of alternative strategies in emergency shortages or resource-scarce settings. Methods We conducted a scoping review of PubMed and grey literature related to facial protection and potential adaptation strategies in the setting of PPE shortages (January 2000 to March 2020). Limitations included few COVID-19-specific studies and exclusion of non-English language articles. We conducted a narrative synthesis of the evidence based on relevant healthcare settings to increase practical utility in decision-making. Results We retrieved 5462 peer-reviewed articles and 41 grey literature records. In total, we included 67 records which met inclusion criteria. Compared with surgical masks, N95 respirators perform better in laboratory testing, may provide superior protection in inpatient settings and perform equivalently in outpatient settings. Surgical mask and N95 respirator conservation strategies include extended use, reuse or decontamination, but these strategies may result in inferior protection. Limited evidence suggests that reused and improvised masks should be used when medical-grade protection is unavailable. Conclusion The COVID-19 pandemic has led to critical shortages of medical-grade PPE. Alternative forms of facial protection offer inferior protection. More robust evidence is required on different types of medical-grade facial protection. As research on COVID-19 advances, investigators should continue to examine the impact on alternatives of medical-grade facial protection.
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Affiliation(s)
| | - Amy E Jones
- School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Taylor N Anderson
- School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Cameron L Fisher
- School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Kylie M L Seeley
- School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Erynn A Beeson
- School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Hannah K Zane
- School of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Jaime W Peterson
- Department of Pediatrics, Oregon Health and Science University Hospital, Portland, Oregon, USA
| | - Peter D Sullivan
- Department of Internal Medicine, Oregon Health and Science University Hospital, Portland, Oregon, USA
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41
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Baerlocher MO, Baerlocher FJ. Overuse/Abuse of the Definition of "Aerosol-Generating Procedures" to Limit Mask Use. J Vasc Interv Radiol 2020; 31:1189-1191. [PMID: 32457009 PMCID: PMC7183985 DOI: 10.1016/j.jvir.2020.04.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Affiliation(s)
- Mark O Baerlocher
- Department of Interventional Radiology, Royal Victoria Hospital, Barrie, Ontario, Canada.
| | - Felix J Baerlocher
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
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42
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Verbeek JH, Rajamaki B, Ijaz S, Sauni R, Toomey E, Blackwood B, Tikka C, Ruotsalainen JH, Kilinc Balci FS. Personal protective equipment for preventing highly infectious diseases due to exposure to contaminated body fluids in healthcare staff. Cochrane Database Syst Rev 2020; 4:CD011621. [PMID: 32293717 PMCID: PMC7158881 DOI: 10.1002/14651858.cd011621.pub4] [Citation(s) in RCA: 163] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND In epidemics of highly infectious diseases, such as Ebola, severe acute respiratory syndrome (SARS), or coronavirus (COVID-19), healthcare workers (HCW) are at much greater risk of infection than the general population, due to their contact with patients' contaminated body fluids. Personal protective equipment (PPE) can reduce the risk by covering exposed body parts. It is unclear which type of PPE protects best, what is the best way to put PPE on (i.e. donning) or to remove PPE (i.e. doffing), and how to train HCWs to use PPE as instructed. OBJECTIVES To evaluate which type of full-body PPE and which method of donning or doffing PPE have the least risk of contamination or infection for HCW, and which training methods increase compliance with PPE protocols. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase and CINAHL to 20 March 2020. SELECTION CRITERIA We included all controlled studies that evaluated the effect of full-body PPE used by HCW exposed to highly infectious diseases, on the risk of infection, contamination, or noncompliance with protocols. We also included studies that compared the effect of various ways of donning or doffing PPE, and the effects of training on the same outcomes. DATA COLLECTION AND ANALYSIS Two review authors independently selected studies, extracted data and assessed the risk of bias in included trials. We conducted random-effects meta-analyses were appropriate. MAIN RESULTS Earlier versions of this review were published in 2016 and 2019. In this update, we included 24 studies with 2278 participants, of which 14 were randomised controlled trials (RCT), one was a quasi-RCT and nine had a non-randomised design. Eight studies compared types of PPE. Six studies evaluated adapted PPE. Eight studies compared donning and doffing processes and three studies evaluated types of training. Eighteen studies used simulated exposure with fluorescent markers or harmless microbes. In simulation studies, median contamination rates were 25% for the intervention and 67% for the control groups. Evidence for all outcomes is of very low certainty unless otherwise stated because it is based on one or two studies, the indirectness of the evidence in simulation studies and because of risk of bias. Types of PPE The use of a powered, air-purifying respirator with coverall may protect against the risk of contamination better than a N95 mask and gown (risk ratio (RR) 0.27, 95% confidence interval (CI) 0.17 to 0.43) but was more difficult to don (non-compliance: RR 7.5, 95% CI 1.81 to 31.1). In one RCT (59 participants), people with a long gown had less contamination than those with a coverall, and coveralls were more difficult to doff (low-certainty evidence). Gowns may protect better against contamination than aprons (small patches: mean difference (MD) -10.28, 95% CI -14.77 to -5.79). PPE made of more breathable material may lead to a similar number of spots on the trunk (MD 1.60, 95% CI -0.15 to 3.35) compared to more water-repellent material but may have greater user satisfaction (MD -0.46, 95% CI -0.84 to -0.08, scale of 1 to 5). Modified PPE versus standard PPE The following modifications to PPE design may lead to less contamination compared to standard PPE: sealed gown and glove combination (RR 0.27, 95% CI 0.09 to 0.78), a better fitting gown around the neck, wrists and hands (RR 0.08, 95% CI 0.01 to 0.55), a better cover of the gown-wrist interface (RR 0.45, 95% CI 0.26 to 0.78, low-certainty evidence), added tabs to grab to facilitate doffing of masks (RR 0.33, 95% CI 0.14 to 0.80) or gloves (RR 0.22, 95% CI 0.15 to 0.31). Donning and doffing Using Centers for Disease Control and Prevention (CDC) recommendations for doffing may lead to less contamination compared to no guidance (small patches: MD -5.44, 95% CI -7.43 to -3.45). One-step removal of gloves and gown may lead to less bacterial contamination (RR 0.20, 95% CI 0.05 to 0.77) but not to less fluorescent contamination (RR 0.98, 95% CI 0.75 to 1.28) than separate removal. Double-gloving may lead to less viral or bacterial contamination compared to single gloving (RR 0.34, 95% CI 0.17 to 0.66) but not to less fluorescent contamination (RR 0.98, 95% CI 0.75 to 1.28). Additional spoken instruction may lead to fewer errors in doffing (MD -0.9, 95% CI -1.4 to -0.4) and to fewer contamination spots (MD -5, 95% CI -8.08 to -1.92). Extra sanitation of gloves before doffing with quaternary ammonium or bleach may decrease contamination, but not alcohol-based hand rub. Training The use of additional computer simulation may lead to fewer errors in doffing (MD -1.2, 95% CI -1.6 to -0.7). A video lecture on donning PPE may lead to better skills scores (MD 30.70, 95% CI 20.14 to 41.26) than a traditional lecture. Face-to-face instruction may reduce noncompliance with doffing guidance more (odds ratio 0.45, 95% CI 0.21 to 0.98) than providing folders or videos only. AUTHORS' CONCLUSIONS We found low- to very low-certainty evidence that covering more parts of the body leads to better protection but usually comes at the cost of more difficult donning or doffing and less user comfort, and may therefore even lead to more contamination. More breathable types of PPE may lead to similar contamination but may have greater user satisfaction. Modifications to PPE design, such as tabs to grab, may decrease the risk of contamination. For donning and doffing procedures, following CDC doffing guidance, a one-step glove and gown removal, double-gloving, spoken instructions during doffing, and using glove disinfection may reduce contamination and increase compliance. Face-to-face training in PPE use may reduce errors more than folder-based training. We still need RCTs of training with long-term follow-up. We need simulation studies with more participants to find out which combinations of PPE and which doffing procedure protects best. Consensus on simulation of exposure and assessment of outcome is urgently needed. We also need more real-life evidence. Therefore, the use of PPE of HCW exposed to highly infectious diseases should be registered and the HCW should be prospectively followed for their risk of infection.
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Affiliation(s)
- Jos H Verbeek
- Academic Medical Center, University of Amsterdam, Cochrane Work Review Group, Amsterdam, Netherlands, 1105AZ
| | - Blair Rajamaki
- University of Eastern Finland, School of Pharmacy, Kuopio, Finland
| | - Sharea Ijaz
- University of Bristol, Population Health Sciences, Bristol Medical School, Bristol, UK, BS1 2NT
| | | | | | - Bronagh Blackwood
- Queen's University Belfast, Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Wellcome-Wolfson Building, 97 Lisburn Road, Belfast, Northern Ireland, UK, BT9 7LB
| | - Christina Tikka
- Finnish Institute of Occupational Health, TYÖTERVEYSLAITOS, Finland, FI-70032
| | - Jani H Ruotsalainen
- Finnish Medicines Agency, Assessment of Pharmacotherapies, Microkatu 1, Kuopio, Finland, FI-70210
| | - F Selcen Kilinc Balci
- Centers for Disease Control and Prevention (CDC), National Personal Protective Technology Laboratory (NPPTL), National Institute for Occupational Safety and Health (NIOSH), 626 Cochrans Mill Road, Pittsburgh, PA, USA, 15236
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Affiliation(s)
- Melissa McDiarmid
- Division of Occupational and Environmental Medicine, University of Maryland School of Medicine, Baltimore
| | - Robert Harrison
- Division of Occupational and Environmental Medicine, University of California, San Francisco
| | - Mark Nicas
- Environmental Health Sciences Division, University of California School of Public Health, Berkeley
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Lindsley WG, Blachere FM, McClelland TL, Neu DT, Mnatsakanova A, Martin SB, Mead KR, Noti JD. Efficacy of an ambulance ventilation system in reducing EMS worker exposure to airborne particles from a patient cough aerosol simulator. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2019; 16:804-816. [PMID: 31638865 DOI: 10.1080/15459624.2019.1674858] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The protection of emergency medical service (EMS) workers from airborne disease transmission is important during routine transport of patients with infectious respiratory illnesses and would be critical during a pandemic of a disease such as influenza. However, few studies have examined the effectiveness of ambulance ventilation systems at reducing EMS worker exposure to airborne particles (aerosols). In our study, a cough aerosol simulator mimicking a coughing patient with an infectious respiratory illness was placed on a patient cot in an ambulance. The concentration and dispersion of cough aerosol particles were measured for 15 min at locations corresponding to likely positions of an EMS worker treating the patient. Experiments were performed with the patient cot at an angle of 0° (horizontal), 30°, and 60°, and with the ambulance ventilation system set to 0, 5, and 12 air changes/hour (ACH). Our results showed that increasing the air change rate significantly reduced the airborne particle concentration (p < 0.001). Increasing the air change rate from 0 to 5 ACH reduced the mean aerosol concentration by 34% (SD = 19%) overall, while increasing it from 0 to 12 ACH reduced the concentration by 68% (SD = 9%). Changing the cot angle also affected the concentration (p < 0.001), but the effect was more modest, especially at 5 and 12 ACH. Contrary to our expectations, the aerosol concentrations at the different worker positions were not significantly different (p < 0.556). Flow visualization experiments showed that the ventilation system created a recirculation pattern which helped disperse the aerosol particles throughout the compartment, reducing the effectiveness of the system. Our findings indicate that the ambulance ventilation system reduced but did not eliminate worker exposure to infectious aerosol particles. Aerosol exposures were not significantly different at different locations within the compartment, including locations behind and beside the patient. Improved ventilation system designs with smoother and more unidirectional airflows could provide better worker protection.
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Affiliation(s)
- William G Lindsley
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Francoise M Blachere
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Tia L McClelland
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Dylan T Neu
- Division of Field Studies & Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
| | - Anna Mnatsakanova
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Stephen B Martin
- Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
| | - Kenneth R Mead
- Division of Field Studies & Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
| | - John D Noti
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA
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Xu SS, Lei Z, Zhuang Z, Bergman M. COMPUTATIONAL FLUID DYNAMICS SIMULATION OF FLOW OF EXHALED PARTICLES FROM POWERED-AIR PURIFYING RESPIRATORS. PROCEEDINGS OF THE ... ASME DESIGN ENGINEERING TECHNICAL CONFERENCES. ASME DESIGN ENGINEERING TECHNICAL CONFERENCES 2019; 1:10.1115/detc2019-97826. [PMID: 37216194 PMCID: PMC10193452 DOI: 10.1115/detc2019-97826] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In surgical settings, infectious particulate wound contamination is a recognized cause of post-operative infections. Powered air-purifying respirators (PAPRs) are widely used by healthcare workers personal protection against infectious aerosols. Healthcare infection preventionists have expressed concern about the possibility that infectious particles expelled from PAPR exhalation channels could lead to healthcare associated infections, especially in operative settings where sterile procedural technique is emphasized. This study used computational fluid dynamics (CFD) modeling to simulate and visualize the distribution of particles exhaled by the PAPR wearer. In CFD simulations, the outward release of the exhaled particles, i.e., ratio of exhaled particle concentration outside the PAPR to that of inside the PAPR, was determined. This study also evaluated the effect of particle sizes, supplied air flow rates, and breathing work rates on outward leakage. This simulation study for the headform and loose-fitting PAPR system included the following four main steps: (1) preprocessing (establishing a geometrical model of a headform wearing a loose-fitting PAPR by capturing a 3D image), (2) defining a mathematical model for the headform and PAPR system, and (3) running a total 24 simulations with four particle sizes, three breathing workloads and two supplied-air flow rates (4×3×2=24) applied on the digital model of the headform and PAPR system, and (4) post-processing the simulation results to visually display the distribution of exhaled particles inside the PAPR and determine the particle concentration of outside the PAPR compared with the concentration inside. We assume that there was no ambient particle, and only exhaled particles existed. The results showed that the ratio of the exhaled particle concentration outside to inside the PAPR were influenced by exhaled particle sizes, breathing workloads, and supplied-air flow rates. We found that outward concentration leakage from PAPR wearers was approximately 9% with a particle size of 0.1 and 1 μm at the light breathing and 205 L/min supplied-air flow rates, which is similar to the respiratory physiology of a health care worker in operative settings, The range of the ratio of exhaled particle concentration leaking outside the PAPR to the exhaled particle concentration inside the PAPR is from 7.6% to 49. We found that supplied air flow rates and work rates have significant impact on outward leakage, the outward concentration leakage increased as particle size decreased, breathing workload increased, and supplied-air flow rate decreased. The results of our simulation study should help provide a foundation for future clinical studies.
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Affiliation(s)
- Susan S Xu
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Pittsburgh, Pennsylvania
| | - Zhipeng Lei
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention Pittsburgh, Pennsylvania
| | - Ziqing Zhuang
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Pittsburgh, Pennsylvania
| | - Michael Bergman
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Pittsburgh, Pennsylvania
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Horender S, Auderset K, Vasilatou K. Facility for calibration of optical and condensation particle counters based on a turbulent aerosol mixing tube and a reference optical particle counter. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:075111. [PMID: 31370453 DOI: 10.1063/1.5095853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/18/2019] [Indexed: 06/10/2023]
Abstract
In this study, we present a custom-made facility developed for evaluating the measurement efficiency of optical particle counters and other common aerosol instrumentation. The facility consists of an aerosol generation setup, a turbulent flow tube for particle homogenization, isokinetic sampling ports, and a home-built particle counter that serves as a reference instrument. Stable and reproducible aerosols of polystyrene latex particles can be produced in the size range 100 nm-10 μm and at concentrations between 0.5 cm-3 and a few thousand submicron particles per cm3 or a few tens of 10 µm particles per cm3. The flow characteristics in the homogenizer were investigated with laser Doppler velocimetry measurements and computational fluid dynamics simulations indicating a plug (turbulent) flow at the aerosol sampling location. The particle mixing characteristics were determined experimentally at various heights of the flow tube by parallel measurements with two condensation particle counters. A spatial homogeneity within 1.1% was found across the sampling area. The measurement uncertainties in the determination of the particle number concentration have been evaluated in detail and amount typically to 5.4% at 1 cm-3 and 2.1% at 100 cm-3 (95% confidence level).
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Affiliation(s)
- Stefan Horender
- Laboratory Particles and Aerosols, Federal Institute of Metrology METAS, Lindenweg 50, 3003 Bern-Wabern, Switzerland
| | - Kevin Auderset
- Laboratory Particles and Aerosols, Federal Institute of Metrology METAS, Lindenweg 50, 3003 Bern-Wabern, Switzerland
| | - Konstantina Vasilatou
- Laboratory Particles and Aerosols, Federal Institute of Metrology METAS, Lindenweg 50, 3003 Bern-Wabern, Switzerland
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Verbeek JH, Rajamaki B, Ijaz S, Tikka C, Ruotsalainen JH, Edmond MB, Sauni R, Kilinc Balci FS. Personal protective equipment for preventing highly infectious diseases due to exposure to contaminated body fluids in healthcare staff. Cochrane Database Syst Rev 2019; 7:CD011621. [PMID: 31259389 PMCID: PMC6601138 DOI: 10.1002/14651858.cd011621.pub3] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND In epidemics of highly infectious diseases, such as Ebola Virus Disease (EVD) or Severe Acute Respiratory Syndrome (SARS), healthcare workers (HCW) are at much greater risk of infection than the general population, due to their contact with patients' contaminated body fluids. Contact precautions by means of personal protective equipment (PPE) can reduce the risk. It is unclear which type of PPE protects best, what is the best way to remove PPE, and how to make sure HCW use PPE as instructed. OBJECTIVES To evaluate which type of full body PPE and which method of donning or doffing PPE have the least risk of self-contamination or infection for HCW, and which training methods increase compliance with PPE protocols. SEARCH METHODS We searched MEDLINE (PubMed up to 15 July 2018), Cochrane Central Register of Trials (CENTRAL up to 18 June 2019), Scopus (Scopus 18 June 2019), CINAHL (EBSCOhost 31 July 2018), and OSH-Update (up to 31 December 2018). We also screened reference lists of included trials and relevant reviews, and contacted NGOs and manufacturers of PPE. SELECTION CRITERIA We included all controlled studies that compared the effects of PPE used by HCW exposed to highly infectious diseases with serious consequences, such as Ebola or SARS, on the risk of infection, contamination, or noncompliance with protocols. This included studies that used simulated contamination with fluorescent markers or a non-pathogenic virus.We also included studies that compared the effect of various ways of donning or doffing PPE, and the effects of training in PPE use on the same outcomes. DATA COLLECTION AND ANALYSIS Two authors independently selected studies, extracted data and assessed risk of bias in included trials. We planned to perform meta-analyses but did not find sufficiently similar studies to combine their results. MAIN RESULTS We included 17 studies with 1950 participants evaluating 21 interventions. Ten studies are Randomised Controlled Trials (RCTs), one is a quasi RCT and six have a non-randomised controlled design. Two studies are awaiting assessment.Ten studies compared types of PPE but only six of these reported sufficient data. Six studies compared different types of donning and doffing and three studies evaluated different types of training. Fifteen studies used simulated exposure with fluorescent markers or harmless viruses. In simulation studies, contamination rates varied from 10% to 100% of participants for all types of PPE. In one study HCW were exposed to Ebola and in another to SARS.Evidence for all outcomes is based on single studies and is very low quality.Different types of PPEPPE made of more breathable material may not lead to more contamination spots on the trunk (Mean Difference (MD) 1.60 (95% Confidence Interval (CI) -0.15 to 3.35) than more water repellent material but may have greater user satisfaction (MD -0.46; 95% CI -0.84 to -0.08, scale of 1 to 5).Gowns may protect better against contamination than aprons (MD large patches -1.36 95% CI -1.78 to -0.94).The use of a powered air-purifying respirator may protect better than a simple ensemble of PPE without such respirator (Relative Risk (RR) 0.27; 95% CI 0.17 to 0.43).Five different PPE ensembles (such as gown vs. coverall, boots with or without covers, hood vs. cap, length and number of gloves) were evaluated in one study, but there were no event data available for compared groups.Alterations to PPE design may lead to less contamination such as added tabs to grab masks (RR 0.33; 95% CI 0.14 to 0.80) or gloves (RR 0.22 95% CI 0.15 to 0.31), a sealed gown and glove combination (RR 0.27; 95% CI 0.09 to 0.78), or a better fitting gown around the neck, wrists and hands (RR 0.08; 95% CI 0.01 to 0.55) compared to standard PPE.Different methods of donning and doffing proceduresDouble gloving may lead to less contamination compared to single gloving (RR 0.36; 95% CI 0.16 to 0.78).Following CDC recommendations for doffing may lead to less contamination compared to no guidance (MD small patches -5.44; 95% CI -7.43 to -3.45).Alcohol-based hand rub used during the doffing process may not lead to less contamination than the use of a hypochlorite based solution (MD 4.00; 95% CI 0.47 to 34.24).Additional spoken instruction may lead to fewer errors in doffing (MD -0.9, 95% CI -1.4 to -0.4).Different types of trainingThe use of additional computer simulation may lead to fewer errors in doffing (MD -1.2, 95% CI -1.6 to -0.7).A video lecture on donning PPE may lead to better skills scores (MD 30.70; 95% CI 20.14,41.26) than a traditional lecture.Face to face instruction may reduce noncompliance with doffing guidance more (OR 0.45; 95% CI 0.21 to 0.98) than providing folders or videos only.There were no studies on effects of training in the long term or on resource use.The quality of the evidence is very low for all comparisons because of high risk of bias in all studies, indirectness of evidence, and small numbers of participants. AUTHORS' CONCLUSIONS We found very low quality evidence that more breathable types of PPE may not lead to more contamination, but may have greater user satisfaction. Alterations to PPE, such as tabs to grab may decrease contamination. Double gloving, following CDC doffing guidance, and spoken instructions during doffing may reduce contamination and increase compliance. Face-to-face training in PPE use may reduce errors more than video or folder based training. Because data come from single small studies with high risk of bias, we are uncertain about the estimates of effects.We still need randomised controlled trials to find out which training works best in the long term. We need better simulation studies conducted with several dozen participants to find out which PPE protects best, and what is the safest way to remove PPE. Consensus on the best way to conduct simulation of exposure and assessment of outcome is urgently needed. HCW exposed to highly infectious diseases should have their use of PPE registered and should be prospectively followed for their risk of infection in the field.
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Affiliation(s)
- Jos H Verbeek
- University of Eastern FinlandCochrane Work Review GroupKuopioFinland70201
| | - Blair Rajamaki
- University of Eastern FinlandInstitute of Public Health and Clinical Nutrition, Occupational Health UnitKuopioFinland
| | - Sharea Ijaz
- University of BristolPopulation Health Sciences, Bristol Medical SchoolBristolUKBS1 2NT
| | - Christina Tikka
- Finnish Institute of Occupational HealthCochrane Work Review GroupTYÖTERVEYSLAITOSFinlandFI‐70032
| | - Jani H Ruotsalainen
- Coronel Institute of Occupational HealthCochrane Work Review GroupAcademic Medical Center, University of AmsterdamPO Box 22700AmsterdamNetherlands1100 DE
| | - Michael B Edmond
- University of Iowa Hospitals and ClinicsC512 GH, 200 Hawkins DriveIowa CityIAUSA52241
| | - Riitta Sauni
- Finnish Institute of Occupational HealthP.O.Box 486TampereFinlandFI‐33101
| | - F Selcen Kilinc Balci
- Centers for Disease Control and Prevention (CDC)National Personal Protective Technology Laboratory (NPPTL), National Institute for Occupational Safety and Health (NIOSH)626 Cochrans Mill RoadPittsburghPAUSA15236
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Practical Guidance for Clinical Microbiology Laboratories: Viruses Causing Acute Respiratory Tract Infections. Clin Microbiol Rev 2018; 32:32/1/e00042-18. [PMID: 30541871 DOI: 10.1128/cmr.00042-18] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Respiratory viral infections are associated with a wide range of acute syndromes and infectious disease processes in children and adults worldwide. Many viruses are implicated in these infections, and these viruses are spread largely via respiratory means between humans but also occasionally from animals to humans. This article is an American Society for Microbiology (ASM)-sponsored Practical Guidance for Clinical Microbiology (PGCM) document identifying best practices for diagnosis and characterization of viruses that cause acute respiratory infections and replaces the most recent prior version of the ASM-sponsored Cumitech 21 document, Laboratory Diagnosis of Viral Respiratory Disease, published in 1986. The scope of the original document was quite broad, with an emphasis on clinical diagnosis of a wide variety of infectious agents and laboratory focus on antigen detection and viral culture. The new PGCM document is designed to be used by laboratorians in a wide variety of diagnostic and public health microbiology/virology laboratory settings worldwide. The article provides guidance to a rapidly changing field of diagnostics and outlines the epidemiology and clinical impact of acute respiratory viral infections, including preferred methods of specimen collection and current methods for diagnosis and characterization of viral pathogens causing acute respiratory tract infections. Compared to the case in 1986, molecular techniques are now the preferred diagnostic approaches for the detection of acute respiratory viruses, and they allow for automation, high-throughput workflows, and near-patient testing. These changes require quality assurance programs to prevent laboratory contamination as well as strong preanalytical screening approaches to utilize laboratory resources appropriately. Appropriate guidance from laboratorians to stakeholders will allow for appropriate specimen collection, as well as correct test ordering that will quickly identify highly transmissible emerging pathogens.
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Kunkel SA, Azimi P, Zhao H, Stark BC, Stephens B. Quantifying the size-resolved dynamics of indoor bioaerosol transport and control. INDOOR AIR 2017; 27:977-987. [PMID: 28190263 DOI: 10.1111/ina.12374] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/07/2017] [Indexed: 06/06/2023]
Abstract
Understanding the bioaerosol dynamics of droplets and droplet nuclei emitted during respiratory activities is important for understanding how infectious diseases are transmitted and potentially controlled. To this end, we conducted experiments to quantify the size-resolved dynamics of indoor bioaerosol transport and control in an unoccupied apartment unit operating under four different HVAC particle filtration conditions. Two model organisms (Escherichia coli K12 and bacteriophage T4) were aerosolized under alternating low and high flow rates to roughly represent constant breathing and periodic coughing. Size-resolved aerosol sampling and settle plate swabbing were conducted in multiple locations. Samples were analyzed by DNA extraction and quantitative polymerase chain reaction (qPCR). DNA from both organisms was detected during all test conditions in all air samples up to 7 m away from the source, but decreased in magnitude with the distance from the source. A greater fraction of T4 DNA was recovered from the aerosol size fractions smaller than 1 μm than E. coli K12 at all air sampling locations. Higher efficiency HVAC filtration also reduced the amount of DNA recovered in air samples and on settle plates located 3-7 m from the source.
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Affiliation(s)
- S A Kunkel
- Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - P Azimi
- Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - H Zhao
- Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - B C Stark
- Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
| | - B Stephens
- Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago, IL, USA
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Cao G, Liu S, Boor BE, Novoselac A. Dynamic interaction of a downward plane jet and a cough jet with respect to particle transmission: An analytical and experimental study. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2017; 14:620-633. [PMID: 28557668 DOI: 10.1080/15459624.2017.1316383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A cough jet can travel beyond the breathing zone of the source person, and thus, infectious viral- and bacterial-laden particles can be transported from the source person to others in close proximity. To reduce the interpersonal transmission of coughed particles, the objective of this study was to analytically and experimentally investigate the performance of downward plane jets with various discharge velocities. Chamber measurements were conducted to examine the interaction between a transient cough jet (discharge velocities of 12 m/sec and 16 m/sec) and a steady downward plane jet (discharge velocities from 1.0-8.5 m/sec) with respect to the transport of and human exposure to coughed particles. The results show that a relatively high-speed cough can easily penetrate a downward plane jet with a discharge velocity of less than 6 m/sec. A downward plane jet with a discharge velocity of 8.5 m/sec can bend the cough jet to a certain extent. In this study, momentum comparison of the cough jet and the downward plane jet shows that the value of personal exposure to coughed particles depends on the ratio of jet momentums. The results show that when the two momentums are equivalent or if the downward plane jet has a greater momentum, the cough jet is deflected downward and does not reach the breathing zone of the target thermal dummy. Using the ratio of the two momentums, it may be estimated whether the transmission of a cough jet can be controlled. A trajectory model was developed based on the ratio of the two momentums of a cough jet and a downward jet and was validated using the experimental data. In addition, the predicted trajectory of the cough jet agreed well with the results from smoke visualization experiments. This model can be used to guide the design of downward plane jet systems for protection of occupants from coughed particles.
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Affiliation(s)
- Guangyu Cao
- a Department of Energy and Process Engineering , Norwegian University of Science and Technology , Trondheim , Norway
| | - Shichao Liu
- b Department of Civil, Architectural, and Environmental Engineering , The University of Texas at Austin , Austin , Texas
- c Center for the Built Environment , University of California , Berkeley , California
| | - Brandon E Boor
- b Department of Civil, Architectural, and Environmental Engineering , The University of Texas at Austin , Austin , Texas
- d Lyles School of Civil Engineering , Purdue University , West Lafayette , Indiana
| | - Atila Novoselac
- b Department of Civil, Architectural, and Environmental Engineering , The University of Texas at Austin , Austin , Texas
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