scholarly journals A quantitative evaluation of aerosol generation during manual facemask ventilation

2021 ◽  
Author(s):  
A. J. Shrimpton ◽  
J. M. Brown ◽  
F. K. A. Gregson ◽  
T. M. Cook ◽  
D.A. Scott ◽  
...  
Keyword(s):  
Particle Concentration ◽  
Direct Evidence ◽  
Tidal Breathing ◽  
Core Component ◽  
Emergency Airway ◽  
Aerosol Generation ◽  
Aerosol Monitoring ◽  
Facemask Ventilation ◽  
Background Particle ◽  
Made In

SummaryManual facemask ventilation, a core component of elective and emergency airway management, is classified as an aerosol generating procedure. This designation is based on a single epidemiological study suggesting an association between facemask ventilation and transmission from the SARS 2003 outbreak. There is no direct evidence to indicate whether facemask ventilation is a high-risk procedure for aerosol generation. We conducted aerosol monitoring during routine facemask ventilation, and facemask ventilation with an intentionally generated leak, in anaesthetised patients with neuromuscular blockade. Recordings were made in ultraclean theatres and compared against the aerosol generated by the patient’s own tidal breathing and coughs. Respiratory aerosol from tidal breathing was reliably detected above the very low background particle concentrations (191 (77-486 [3.8-1313]) versus 2.1 (0.7-4.6 [0-12.9] particles.l-1 median(IQR)[range], n=11, p=0.002). The average aerosol concentration detected during facemask ventilation both without a leak (3.0 particles.l-1 (0 – 9 [0-43])) and with an intentional leak (11 particles.l-1 (7.0 – 26 [1-62])) was 64-fold and 17-fold lower than that of tidal breathing (p=0.001 and p=0.002 respectively). The peak particle concentration during facemask ventilation both without a leak (60 particles.l-1 (0 – 60 [0-120])) and with a leak (120 particles.l-1 (60 – 180 [60-480]) were respectively 20-fold and 10-fold lower than a cough (1260 particles (800 – 3242 [100-3682]), p=0.002 and p=0.001 respectively). This study demonstrates that facemask ventilation, even performed with an intentional leak, does not generate high levels of bioaerosol. On the basis of this evidence, facemask ventilation should not be considered an aerosol generating procedure.

scholarly journals Identification of the source events for aerosol generation during oesophago-gastro-duodenoscopy

Gut ◽  
2021 ◽  
pp. gutjnl-2021-324588
Author(s):  
Florence K A Gregson ◽  
Andrew J Shrimpton ◽  
Fergus Hamilton ◽  
Tim M Cook ◽  
Jonathan P Reid ◽  
...  
Keyword(s):  
Particle Concentration ◽  
Particle Number ◽  
Protective Equipment ◽  
Average Particle ◽  
Respiratory Pathogens ◽  
Tidal Breathing ◽  
Aerosol Generation ◽  
Wide Range ◽  
Monitoring Study ◽  
Particle Sizer

ObjectiveTo determine if oesophago-gastro-duodenoscopy (OGD) generates increased levels of aerosol in conscious patients and identify the source events.DesignA prospective, environmental aerosol monitoring study, undertaken in an ultraclean environment, on patients undergoing OGD. Sampling was performed 20 cm away from the patient’s mouth using an optical particle sizer. Aerosol levels during OGD were compared with tidal breathing and voluntary coughs within subject.ResultsPatients undergoing bariatric surgical assessment were recruited (mean body mass index 44 and mean age 40 years, n=15). A low background particle concentration in theatres (3 L−1) enabled detection of aerosol generation by tidal breathing (mean particle concentration 118 L−1). Aerosol recording during OGD showed an average particle number concentration of 595 L−1 with a wide range (3–4320 L−1). Bioaerosol-generating events, namely, coughing or burping, were common. Coughing was evoked in 60% of the endoscopies, with a greater peak concentration and a greater total number of sampled particles than the patient’s reference voluntary coughs (11 710 vs 2320 L−1 and 780 vs 191 particles, n=9 and p=0.008). Endoscopies with coughs generated a higher level of aerosol than tidal breathing, whereas those without coughs were not different to the background. Burps also generated increased aerosol concentration, similar to those recorded during voluntary coughs. The insertion and removal of the endoscope were not aerosol generating unless a cough was triggered.ConclusionCoughing evoked during OGD is the main source of the increased aerosol levels, and therefore, OGD should be regarded as a procedure with high risk of producing respiratory aerosols. OGD should be conducted with airborne personal protective equipment and appropriate precautions in those patients who are at risk of having COVID-19 or other respiratory pathogens.

scholarly journals Girding the loins? Direct evidence of the use of a medieval parchment birthing girdle from biomolecular analysis

2020 ◽  
Author(s):  
Sarah Fiddyment ◽  
Natalie J. Goodison ◽  
Elma Brenner ◽  
Stefania Signorello ◽  
Kierri Price ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Extraction Method ◽  
Sampling Method ◽  
Direct Evidence ◽  
Vaginal Fluid ◽  
Non Invasive ◽  
Biomolecular Analysis ◽  
Made In

AbstractIn this paper we describe a dry non-invasive extraction method to detect palaeoproteomic evidence from stained manuscripts. The manuscript analysed in this study is a medieval parchment birth girdle (Wellcome Collection Western MS. 632) made in England and thought to be used by pregnant women while giving birth. Using a dry non-invasive sampling method we were able to extract both human and non-human peptides from the stains, including evidence for the use of honey, cereals, ovicaprine milk and legumes. In addition, a large number of human peptides were detected on the birth roll, many of which are found in cervico-vaginal fluid. This suggests that the birth roll was actively used during childbirth. This study is the first to extract and analyse non-collagenous peptides from a parchment document using a dry non-invasive sampling method and demonstrates the potential of this type of analysis for stained manuscripts, providing direct biomolecular evidence for active use.

scholarly journals Microdebrider is less aerosol-generating than CO2 laser and cold instruments in microlaryngoscopy

2021 ◽  
Author(s):  
Enni Sanmark ◽  
Lotta-Maria A. H. Oksanen ◽  
Noora Rantanen ◽  
Mari Lahelma ◽  
Veli-Jukka Anttila ◽  
...  
Keyword(s):  
High Risk ◽  
Surgical Procedures ◽  
Particle Concentration ◽  
Aerosol Particles ◽  
Aerosol Generation ◽  
Laryngeal Surgery ◽  
Step Down ◽  
Particle Sizer ◽  
Measured Particle ◽  
Cold Dissection

Abstract Objective COVID-19 spreads through aerosols produced in coughing, talking, exhalation, and also in some surgical procedures. Use of CO2 laser in laryngeal surgery has been observed to generate aerosols, however, other techniques, such cold dissection and microdebrider, have not been sufficiently investigated. We aimed to assess whether aerosol generation occurs during laryngeal operations and the effect of different instruments on aerosol production. Methods We measured particle concentration generated during surgeries with an Optical Particle Sizer. Cough data collected from volunteers and aerosol concentration of an empty operating room served as references. Aerosol concentrations when using different techniques and equipment were compared with references as well as with each other. Results Thirteen laryngological surgeries were evaluated. The highest total aerosol concentrations were observed when using CO2 laser and these were significantly higher than the concentrations when using microdebrider or cold dissection (p < 0.0001, p < 0.0001) or in the background or during coughing (p < 0.0001, p < 0.0001). In contrast, neither microdebrider nor cold dissection produced significant concentrations of aerosol compared with coughing (p = 0.146, p = 0.753). In comparing all three techniques, microdebrider produced the least aerosol particles. Conclusions Microdebrider and cold dissection can be regarded as aerosol-generating relative to background reference concentrations, but they should not be considered as high-risk aerosol-generating procedures, as the concentrations are low and do not exceed those of coughing. A step-down algorithm from CO2 laser to cold instruments and microdebrider is recommended to lower the risk of airborne infections among medical staff.

scholarly journals Girding the loins? Direct evidence of the use of a medieval English parchment birthing girdle from biomolecular analysis

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Sarah Fiddyment ◽  
Natalie J. Goodison ◽  
Elma Brenner ◽  
Stefania Signorello ◽  
Kierri Price ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Fifteenth Century ◽  
Sampling Method ◽  
Direct Evidence ◽  
Sampling Technique ◽  
Vaginal Fluid ◽  
Non Invasive ◽  
Late Fifteenth ◽  
Biomolecular Analysis ◽  
Made In

In this paper, we describe palaeoproteomic evidence obtained from a stained medieval birth girdle using a previously developed dry non-invasive sampling technique. The parchment birth girdle studied (Wellcome Collection Western MS. 632) was made in England in the late fifteenth century and was thought to be used by pregnant women while giving birth. We were able to extract both human and non-human peptides from the manuscript, including evidence for the use of honey, cereals, ovicaprine milk and legumes. In addition, a large number of human peptides were detected on the birth roll, many of which are found in cervico-vaginal fluid. This suggests that the birth roll was actively used during childbirth. This study is, to our knowledge, the first to extract and analyse non-collagenous peptides from a birth girdle using this sampling method and demonstrates the potential of this type of analysis for stained manuscripts, providing direct biomolecular evidence for active use.

scholarly journals Anthroponymy and Toponymy in Memorial Epigraphy of Podlasie

2021 ◽  
Vol 18 (1) ◽  
pp. 62-84
Author(s):  
Olga V. Belova ◽  
◽  
Maria V. Yasinskaya ◽  
Keyword(s):  
Place Names ◽  
High Concentration ◽  
Core Component ◽  
Local Dialect ◽  
Local Tradition ◽  
Different Types ◽  
Russian Literary ◽  
Polish Language ◽  
Made In ◽  
State Language

The paper presents an analysis of personal and place names on the tombstones of necropolises surveyed during a three-year fieldwork in Podlasie province (Hajnówka region), the area of high concentration of Orthodox East Slavic population. Apart from reflecting local dialect features specific to the East Slavic language situation on the Polish-East Slavic borderland, these epigraphic inscriptions made in Cyrillic are also a confessional marker that is highly relevant to the regional Orthodox population’s self-identification. Tombstone inscriptions evidence to the overlapping of Belarusian, Ukrainian, Russian (Church Slavonic), and Polish language contexts. Graphics (Cyrillic) and spelling features of different types of tombstone onyms not only give a picture of ethno-confessional and ethno-linguistic contacts, but also reflect live pronunciation captured in writing. Regarding personal name as a core component of the epitaph and analyzing specific examples, the authors address the following questions: 1) what do graphics and spelling convey in each particular case — the sound form of a name or toponym, writing traditions, focus on a particular spelling norm? 2) what is the reason for the variability in the spelling of the same name, surname, toponym? 3) can we trace the general trends in personal and place names rendering in the local tradition under study? 4) what effect does the Polish (state) language have in the texts that do not aim to comply with Belarusian, Ukrainian or Russian literary spelling norm? In the epigraphy of the studied region, there is a clear preference for using different spelling systems (not necessarily consistent), as reflected in the use of the letters и, ы, i in different combinations. Hence, the Polish spelling sometimes affects the Cyrillic transliteration of some names and surnames.

Sedimentary Infillings of Fossils and Cavities in Limestone at Treak Cliff, Derbyshire

1967 ◽  
Vol 104 (5) ◽  
pp. 443-448 ◽  
Author(s):  
F. M. Broadhurst ◽  
I. M. Simpson
Keyword(s):  
Direct Evidence ◽  
First Time ◽  
Made In

ABSTRACTObservations of partial and complete sedimentary infillings of fossils and rock cavities at two localities on Treak Cliff, Castleton, Derbyshire, lead to the conclusion that at these localities the present dip of the limestones is largely or entirely depositional in origin. This conclusion agrees, more or less, with claims made in previous publications but, so far as the authors are aware, this is the first time that direct evidence of high initial dips at Treak Cliff has been recorded.

On the Role of Coriolis Force in a Two-Dimensional Thermally Driven Flow in a Rotating Enclosure

2006 ◽  
Vol 129 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Nadeem Hasan ◽  
Sanjeev Sanghi
Keyword(s):  
Coriolis Force ◽  
Direct Evidence ◽  
Temperature Fields ◽  
Two Dimensional ◽  
Coriolis Forces ◽  
Active Involvement ◽  
Thermal Boundary Conditions ◽  
Thermally Driven ◽  
Made In

In this work the role of Coriolis forces in the evolution of a two-dimensional thermally driven flow in a rotating enclosure of arbitrary geometry is discussed. Contrary to the claims made in some of the studies involving such class of flows that there is an active involvement of the these forces in the dynamics of the flow, it is shown that the Coriolis force does not play any role in the evolution of the velocity and temperature fields. This is theoretically demonstrated by recognizing the irrotational character of the Coriolis force in such class of flows. It is further shown that the presence of the irrotational Coriolis force affects only the pressure distribution in the rotating enclosure. The theoretical deductions apply quite generally to any geometry and thermal boundary conditions associated with the enclosure. The numerical results for the problem of two-dimensional thermally driven flow of air (Pr=0.71) in a circular rotating enclosure provide direct evidence of the theoretical deductions.

scholarly journals Cryogenic Aerosol Generation: Airborne Mist Particles Surrounding Liquid Nitrogen

2020 ◽  
Vol 17 (3) ◽  
pp. 1071 ◽  
Author(s):  
Byung Uk Lee
Keyword(s):  
Liquid Nitrogen ◽  
Particle Concentration ◽  
Fold Increase ◽  
Particle Counter ◽  
Aerosol Generation ◽  
Optical Particle Counter ◽  
Generation Mechanisms ◽  
Surrounding Liquid

Aerosol mist particles generated near the surface of a liquid nitrogen container were measured and analyzed. The particles present at various distances from the boiling surface of liquid nitrogen were detected using an optical particle counter. In this experiment, 3 micrometer particles exhibited a more than 100-fold increase in concentration due to the liquid nitrogen surface. However, 0.3 micrometer and 10 micrometer particles showed smaller variations (2% to 79%) in their concentrations in the vicinity of liquid nitrogen. The distance from the boiling surface of the liquid nitrogen strongly affected the variations in particle concentration. The variations in aerosol concentrations were significant within 20 cm of the liquid nitrogen surface. These results can be considered as a useful quantitative environmental guideline in cryogenic studies that use liquid nitrogen, and this concept can be applied to cryogenic aerosol mist generation mechanisms.

scholarly journals VOC measurements within a boreal forest during spring 2005: on the occurrence of elevated monoterpene concentrations during night time intense particle concentration events

2009 ◽  
Vol 9 (21) ◽  
pp. 8331-8350 ◽  
Author(s):  
G. Eerdekens ◽  
N. Yassaa ◽  
V. Sinha ◽  
P. P. Aalto ◽  
H. Aufmhoff ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Particle Concentration ◽  
Trace Gases ◽  
Measurement Data ◽  
Event Type ◽  
Night Time ◽  
Back Trajectories ◽  
Vertical Variations ◽  
Natural Monoterpene ◽  
Made In

Abstract. In this study we present measurements of selected trace gases and aerosols made in a boreal forest during the BACCI-QUEST IV intensive field campaign in Hyytiälä, Finland in April 2005. Springtime diel and vertical variations of VOCs are discussed in connection with the variations in other trace gases and with the prevailing meteorological conditions. A daytime and a nighttime event have been analysed in detail. The nighttime particle event occurred synchronously with huge increases in monoterpenes, while the second event type involved nucleation and was anti-correlated with sulphuric acid. Here we discuss the possible origins of these two distinct forms of aerosol production at the Hyytiälä site using the measurement data, air mass back trajectories and the optical stereoisomery of monoterpenes. Optical stereoisomery is used in source identification to distinguish between unnatural and natural monoterpene emissions.

Forced oscillatory respiratory parameters following papain exposure in dogs

1979 ◽  
Vol 46 (1) ◽  
pp. 61-66 ◽  
Author(s):  
A. G. Haddad ◽  
R. L. Pimmel ◽  
D. D. Scaperoth ◽  
P. A. Bromberg
Keyword(s):  
Chest Wall ◽  
Elastic Properties ◽  
Respiratory Mechanics ◽  
Dynamic Compliance ◽  
Lung Mechanics ◽  
Tidal Breathing ◽  
Impedance Data ◽  
Respiratory Parameters ◽  
Before And After ◽  
Made In

Respiratory mechanics were studied in nine intubated dogs before and after exposure to aerosolized papain under conditions known to produce emphysemalike lesions. Forced oscillatory resistance (RFO), compliance (CFO), and inertance (IFO) were computed from impedance data obtained at transrespiratory pressures of -10, 0 (FRC), +10, and +20 cmHWO. Dynamic compliance during tidal breathing (CTB) was also measured at FRC. After papain exposure CTB and CFO increased by 25% (P less than 0.05) at FRC and at +10 cmH2O. There were no consistent changes in RFO or IFO at FRC. However, RFO showed a greater dependency on transrespiratory pressure, which suggests that the elastic properties of airways may also have been affected by papain. Measurements made in open-chested papain-exposed animals showed that about 17% of total RFO and 20% of total elastance were attributable to the chest wall. Forced oscillatory impedance data are sensitive to experimental changes in lung mechanics and provide useful estimates of standard respiratory parameters.

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