Investigation of the Quantity of Exhaled Aerosols Released into the Environment during Nebulisation

McGrath, James J.; O’Sullivan, Andrew; Bennett, Gavin; O’Toole, Ciarraí; Joyce, Mary; Byrne, Mary; MacLoughlin, Ronan

doi:10.3390/pharmaceutics11020075

Cited by 48 publications

(63 citation statements)

References 31 publications

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“…The size of the aerosol and flow are determined by the exit diameter of the aperture holes [35]. Previous research showed that the residual mass remaining in a VMN was independent of the patient interface, heating and humidification settings [26,28]. As the same VMN was used for each scenario, the aerosol generation rate should be consistent across all scenarios with changes in inhaled dose and fugitive emissions influenced by the patient interface, the gas-flow rate and the breathing profiles.…”

Section: Discussionmentioning

confidence: 99%

Investigation of Fugitive Aerosols Released into the Environment during High-Flow Therapy

et al. 2019

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Background: Nebulised medical aerosols are designed to deliver drugs to the lungs to aid in the treatment of respiratory diseases. However, an unintended consequence is the potential for fugitive emissions during patient treatment, which may pose a risk factor in both clinical and homecare settings. Methods: The current study examined the potential for fugitive emissions, using albuterol sulphate as a tracer aerosol during high-flow therapy. A nasal cannula was connected to a head model or alternatively, a interface was connected to a tracheostomy tube in combination with a simulated adult and paediatric breathing profile. Two aerodynamic particle sizers (APS) recorded time-series aerosol concentrations and size distributions at two different distances relative to the simulated patient. Results: The results showed that the quantity and characteristics of the fugitive emissions were influenced by the interface type, patient type and supplemental gas-flow rate. There was a trend in the adult scenarios; as the flow rate increased, the fugitive emissions and the mass median aerodynamic diameter (MMAD) of the aerosol both decreased. The fugitive emissions were comparable when using the adult breathing profiles for the nasal cannula and tracheostomy interfaces; however, there was a noticeable distinction between the two interfaces when compared for the paediatric breathing profiles. The highest recorded aerosol concentration was 0.370 ± 0.046 mg m−3 from the tracheostomy interface during simulated paediatric breathing with a gas-flow rate of 20 L/min. The averaged MMAD across all combinations ranged from 1.248 to 1.793 µm by the APS at a distance of 0.8 m away from the patient interface. Conclusions: Overall, the results highlight the potential for secondary inhalation of fugitive emissions released during simulated aerosol treatment with concurrent high-flow therapy. The findings will help in developing policy and best practice for risk mitigation from fugitive emissions.

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Section: Discussionmentioning

confidence: 99%

Investigation of Fugitive Aerosols Released into the Environment during High-Flow Therapy

et al. 2019

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“…Respiratory infectious diseases can be transmitted via three routes, namely contact, airborne and fomite [27]. Similarly, a higher risk of infection is associated with close proximity to the source patient and decrease rapidly with the distance [28][29][30][31][32][33]. With the same initial concentration, a larger quantity of mass released may be expected to experience a slower dilution [34,35].…”

Section: Graphical Abstractmentioning

confidence: 99%

“…With the same initial concentration, a larger quantity of mass released may be expected to experience a slower dilution [34,35]. Due to the initial velocity, the exhaled gas and particles can travel in the air over a distance which is determined by the ventilation airflow, gravity force related to particle diameters and buoyancy forces of thermal J o u r n a l P r e -p r o o f bodies [16,17,26,31,33,[36][37][38]. Larger particles (>50μm) may settle on wall surfaces or floors quickly because the significance of gravity is greater than ventilation.…”

Section: Graphical Abstractmentioning

confidence: 99%

“…Gravity plays a particularly important role for the movement of large droplets (50μm) [16,31,33,38,40,42]. Thus, to better reveal the influence of air condition supply wind, the following subsection focuses on the analysis of the 10 μm droplet diffusion in different air condition supply modes as RH = 35%.…”

Section: Droplet Diffusion Under Different Air-conditioning Supply Modesmentioning

confidence: 99%

“…As previously investigated [16,23,26,31,33,[38][39][40]42], the particle/droplet dispersion process is greatly determined by the gravity force. In this study, the impacts of different initial droplet sizes and its evaporation rate are discussed.…”

Section: Effect Of the Initial Size Of Droplets On Diffusionmentioning

confidence: 99%

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Transmission of pathogen-laden expiratory droplets in a coach bus

Xia

Yang

et al. 2020

Journal of Hazardous Materials

159

108

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J o u r n a l P r e -p r o o f  RH=95% induces less droplets suspended in air and more deposition fraction(85%-100%). Wet air, sitting at nonadjacent seats, supply to bus backward reduce infection risk. AbstractDroplet dispersion carrying viruses/bacteria in enclosed/crowded buses may induce transmissions of respiratory infectious diseases, but the influencing mechanisms have been rarely investigated. By conducting high-resolution CFD simulations, this paper investigates the evaporation and transport of solid-liquid mixed droplets (initial diameter 10μm and 50μm, solid to liquid ratio is 1:9) exhaled in a coach bus with 14 thermal manikins. Five air-conditioning supply directions and ambient relative humidity (RH=35% and 95%) are considered. Results show that ventilation effectiveness, RH and initial droplet size significantly influence droplet transmissions in coach bus. 50μm droplets tend to evaporate completely within 1.8s and 7s as RH=35% and 95% respectively, while 0.2s or less for 10μm droplets. Thus 10μm droplets diffuse farther with wider range than 50μm droplets which tend to deposit more on surfaces. Droplet dispersion pattern differs due to various interactions of gravity, ventilation flows and the upward thermal body plume. The fractions of droplets suspended in air, deposited on wall surfaces are quantified. This study implies high RH, backward supply direction and passengers sitting at nonadjacent seats can effectively reduce infection risk of droplet transmission in buses. Besides taking masks, regular cleaning is also recommended since 85%-100% of droplets deposit on object surfaces.J o u r n a l P r e -p r o o f

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Quantifying continuous nebulization via high flow nasal cannula and large volume nebulizer in a pediatric model

Moody

Ari

2020

Pediatric Pulmonology

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Background Use of high flow nasal cannula (HFNC) to deliver aerosolized medications to children has gained considerable interest. However, data on continuous albuterol delivery (CAD) via HFNC are lacking. This study quantified CAD via HFNC/vibrating mesh nebulizer (VMN) and large‐volume jet nebulizer (LVN) with face mask (FM) in a pediatric model. Aerosol delivery with two HFNC cannula designs were also compared. Methods A pediatric manikin was connected to a lung simulator (Vt = 150 mL, RR = 28 breaths/minute, I:E 1:2.4) via collecting filter at the carina. XL Pediatric and SML Adult HFNC designs were tested to determine optimal cannula design for CAD. VMN was placed Before humidifier (37°C), albuterol (5 mg/mL) was nebulized at 3, 6, and 12 L/minute (n = 3). To compare HFNC/VMN with LVN and FM, albuterol (15 mg/hour) was aerosolized for 3 hours/device (n = 3). LVN was connected to FM and filled with 9 mL of albuterol (5 mg/mL) and 66 mL of normal saline to deliver 25 mL/hour at 13 L/minute. VMN was connected to the infusion pump to deliver 7.5 mL/hr of albuterol (2 mg/mL). Drug eluted from filters was assayed with UV spectrophotometry (276 nm). Results Optimal aerosol delivery occurred at 3 L/minute (12.6% ± 0.5%) with SML Adult HFNC (P = .04). When used for CAD, inhaled drug delivery with HFNC/VMN (2.2 mg/hr ± 0.1, 14.8% ± 0.7%) was significantly greater than LVN and FM (0.48 ± 0.09 mg/hour, 3.2% ± 0.6%) (P = .001). Conclusions Administration of CAD via HFNC/VMN led to a greater than fourfold increase in drug delivery compared to LVN with FM. Optimal aerosol delivery occurred at 3 L/minute with SML Adult HFNC.

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Investigation of the Quantity of Exhaled Aerosols Released into the Environment during Nebulisation

Cited by 48 publications

References 31 publications

Investigation of Fugitive Aerosols Released into the Environment during High-Flow Therapy

Investigation of Fugitive Aerosols Released into the Environment during High-Flow Therapy

Transmission of pathogen-laden expiratory droplets in a coach bus

Quantifying continuous nebulization via high flow nasal cannula and large volume nebulizer in a pediatric model

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