Nebuliser Type Influences Both Patient-Derived Bioaerosol Emissions and Ventilation Parameters during Mechanical Ventilation

COVID-19 may lead to serious respiratory complications which may necessitate ventilatory support. There is concern surrounding potential release of patient-derived bioaerosol during nebuliser drug refill, which could impact the health of caregivers. Consequently, mesh nebulisers have been recommended by various clinical practice guidelines. Currently, there is a lack of empirical data describing the potential for release of patient-derived bioaerosol during drug refill. This study examined the release of simulated patient-derived bioaerosol, and the effect on positive end expiratory pressure during nebuliser refill during mechanical ventilation of a simulated patient. During jet nebuliser refill, the positive end expiratory pressure decreased from 4.5 to 0 cm H2O. No loss in pressure was noted during vibrating mesh nebuliser refill. A median particle number concentration of 710 particles cm−3 above ambient was detected when refilling the jet nebuliser in comparison to no increase above ambient detected when using the vibrating mesh nebuliser. The jet nebuliser with the endotracheal tube clamped resulted in 60 particles cm−3 above ambient levels. This study confirms that choice of nebuliser impacts both the potential for patient-derived bioaerosol release and the ability to maintain ventilator circuit pressures and validates the recommended use of mesh nebulisers during mechanical ventilation.

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Ambient Levels of TSP, PM10, PM2.5 and Particle Number Concentration in Al Samha, UAE

Journal of Environmental Protection ◽

10.4236/jep.2017.89063 ◽

2017 ◽

Vol 08 (09) ◽

pp. 1002-1017 ◽

Cited By ~ 1

Author(s):

Fadi A. Al-Jallad ◽

Clarence C. Rodrigues ◽

Hamda A. Al-Thani

Keyword(s):

Particle Number ◽

Number Concentration ◽

Particle Number Concentration ◽

Ambient Levels

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41. Conversion of Particle Number to Beryllium Particle Number Concentration

10.3320/1.2765949 ◽

2001 ◽

Cited By ~ 1

Author(s):

M. Berakis ◽

M. McCawley ◽

M. Kent

Keyword(s):

Particle Number ◽

Number Concentration ◽

Particle Number Concentration

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Faculty Opinions recommendation of Mechanical ventilation with lower tidal volumes and positive end-expiratory pressure prevents pulmonary inflammation in patients without preexisting lung injury.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1101034.558187 ◽

2008 ◽

Author(s):

Jesús Villar

Keyword(s):

Mechanical Ventilation ◽

Lung Injury ◽

Pulmonary Inflammation ◽

Positive End Expiratory Pressure

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Faculty Opinions recommendation of Effect of Titrating Positive End-Expiratory Pressure (PEEP) With an Esophageal Pressure-Guided Strategy vs an Empirical High PEEP-Fio2 Strategy on Death and Days Free From Mechanical Ventilation Among Patients With Acute Respiratory Distress Syndrome: A Randomized Clinical Trial.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.735110597.793560070 ◽

2019 ◽

Author(s):

Jesús Villar

Keyword(s):

Clinical Trial ◽

Mechanical Ventilation ◽

Acute Respiratory Distress Syndrome ◽

Respiratory Distress Syndrome ◽

Respiratory Distress ◽

Randomized Clinical Trial ◽

Distress Syndrome ◽

Esophageal Pressure ◽

High Peep ◽

Positive End Expiratory Pressure

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Regional Lung Derecruitment and Inflammation during 16 Hours of Mechanical Ventilation in Supine Healthy Sheep

Anesthesiology ◽

10.1097/aln.0b013e31829083b8 ◽

2013 ◽

Vol 119 (1) ◽

pp. 156-165 ◽

Cited By ~ 10

Author(s):

Mauro R. Tucci ◽

Eduardo L. V. Costa ◽

Tyler J. Wellman ◽

Guido Musch ◽

Tilo Winkler ◽

...

Keyword(s):

Mechanical Ventilation ◽

Hypoxic Pulmonary Vasoconstriction ◽

Regions Of Interest ◽

Positive End Expiratory Pressure ◽

18F Fluorodeoxyglucose ◽

Positron Emission ◽

Lung Dysfunction ◽

Regional Lung ◽

Net Uptake ◽

Normal Lungs

Abstract Background: Lung derecruitment is common during general anesthesia. Mechanical ventilation with physiological tidal volumes could magnify derecruitment, and produce lung dysfunction and inflammation. The authors used positron emission tomography to study the process of derecruitment in normal lungs ventilated for 16 h and the corresponding changes in regional lung perfusion and inflammation. Methods: Six anesthetized supine sheep were ventilated with VT = 8 ml/kg and positive end-expiratory pressure = 0. Transmission scans were performed at 2-h intervals to assess regional aeration. Emission scans were acquired at baseline and after 16 h for the following tracers: (1) 18F-fluorodeoxyglucose to evaluate lung inflammation and (2) 13NN to calculate regional perfusion and shunt fraction. Results: Gas fraction decreased from baseline to 16 h in dorsal (0.31 ± 0.13 to 0.14 ± 0.12, P < 0.01), but not in ventral regions (0.61 ± 0.03 to 0.63 ± 0.07, P = nonsignificant), with time constants of 1.5–44.6 h. Although the vertical distribution of relative perfusion did not change from baseline to 16 h, shunt increased in dorsal regions (0.34 ± 0.23 to 0.63 ± 0.35, P < 0.01). The average pulmonary net 18F-fluorodeoxyglucose uptake rate in six regions of interest along the ventral–dorsal direction increased from 3.4 ± 1.4 at baseline to 4.1 ± 1.5⋅10−3/min after 16 h (P < 0.01), and the corresponding average regions of interest 18F-fluorodeoxyglucose phosphorylation rate increased from 2.0 ± 0.2 to 2.5 ± 0.2⋅10−2/min (P < 0.01). Conclusions: When normal lungs are mechanically ventilated without positive end-expiratory pressure, loss of aeration occurs continuously for several hours and is preferentially localized to dorsal regions. Progressive lung derecruitment was associated with increased regional shunt, implying an insufficient hypoxic pulmonary vasoconstriction. The increased pulmonary net uptake and phosphorylation rates of 18F-fluorodeoxyglucose suggest an incipient inflammation in these initially normal lungs.

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Impact on Ultrafine Particles Concentration and Turbulent Fluxes of SARS-CoV-2 Lockdown in a Suburban Area in Italy

Atmosphere ◽

10.3390/atmos12030407 ◽

2021 ◽

Vol 12 (3) ◽

pp. 407

Author(s):

Antonio Donateo ◽

Adelaide Dinoi ◽

Gianluca Pappaccogli

Keyword(s):

Ultrafine Particles ◽

Particle Number ◽

Ultrafine Particle ◽

Turbulent Fluxes ◽

Number Concentration ◽

Suburban Area ◽

Observation Site ◽

Meteorological Forcing ◽

Restrictive Measures ◽

Measurement Area

In order to slow the spread of SARS-CoV-2, governments have implemented several restrictive measures (lockdown, stay-in-place, and quarantine policies). These provisions have drastically changed the routines of residents, altering environmental conditions in the affected areas. In this context, our work analyzes the effects of the reduced emissions during the COVID-19 period on the ultrafine particles number concentration and their turbulent fluxes in a suburban area. COVID-19 restrictions did not significantly reduce anthropogenic related PM10 and PM2.5 levels, with an equal decrement of about 14%. The ultrafine particle number concentration during the lockdown period decreased by 64% in our measurement area, essentially due to the lower traffic activity. The effect of the restriction measures and the reduction of vehicles traffic was predominant in reducing concentration rather than meteorological forcing. During the lockdown in 2020, a decrease of 61% in ultrafine particle positive fluxes can be observed. At the same time, negative fluxes decreased by 59% and our observation site behaved, essentially, as a sink of ultrafine particles. Due to this behavior, we can conclude that the principal particle sources during the lockdown were far away from the measurement site.

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Management of Intraoperative Mechanical Ventilation to Prevent Postoperative Complications after General Anesthesia: A Narrative Review

Journal of Clinical Medicine ◽

10.3390/jcm10122656 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2656

Author(s):

Alberto Fogagnolo ◽

Federica Montanaro ◽

Lou’i Al-Husinat ◽

Cecilia Turrini ◽

Michela Rauseo ◽

...

Keyword(s):

Mechanical Ventilation ◽

Tidal Volume ◽

Pulmonary Complications ◽

Point Of View ◽

Whole Body ◽

Positive End Expiratory Pressure ◽

Ventilation Strategies ◽

Harmful Effects ◽

Ventilation Induced Lung Injury ◽

Different Levels

Mechanical ventilation (MV) is still necessary in many surgical procedures; nonetheless, intraoperative MV is not free from harmful effects. Protective ventilation strategies, which include the combination of low tidal volume and adequate positive end expiratory pressure (PEEP) levels, are usually adopted to minimize the ventilation-induced lung injury and to avoid post-operative pulmonary complications (PPCs). Even so, volutrauma and atelectrauma may co-exist at different levels of tidal volume and PEEP, and therefore, the physiological response to the MV settings should be monitored in each patient. A personalized perioperative approach is gaining relevance in the field of intraoperative MV; in particular, many efforts have been made to individualize PEEP, giving more emphasis on physiological and functional status to the whole body. In this review, we summarized the latest findings about the optimization of PEEP and intraoperative MV in different surgical settings. Starting from a physiological point of view, we described how to approach the individualized MV and monitor the effects of MV on lung function.

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