Small droplet emission in exhaled breath during different breathing manoeuvres: Implications for clinical lung function testing during COVID‐19

Greening, Neil; Larsson, Petter; Ljungström, Evert; Siddiqui, Salman; Olin, Anna‐Carin

doi:10.1111/all.14596

Cited by 23 publications

(35 citation statements)

References 8 publications

(8 reference statements)

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“…The second study (19) included 33 healthy volunteers who performed different respiratory manoeuvres outside of ultra clean, environment. Like our data they found coughing was the highest aerosol-producing manoeuvre and interestingly they found that increased expiratory flow rates did not increase aerosol production.…”

Section: Discussionmentioning

confidence: 99%

Risk and mitigation of aerosolisation from lung function testing: results from the AERATOR study

Sheikh

Hamilton

Nava

et al. 2021

Preprint

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Introduction Lung function tests are fundamental diagnostic and monitoring tools for patients with respiratory symptoms. There is significant uncertainty around whether potentially infectious aerosol is produced during different lung function testing modalities; and limited data on possible mitigation strategies to reduce risk to staff and limit fallow time. Methods Healthy volunteers were recruited in an ultraclean, laminar flow theatre and had standardised spirometry as per ERS/ATS guidance, as well as peak flow measurement and FENO assessment of airway inflammation. Aerosol emission was sampled once each second using both Aerodynamic Particle Sizer (APS) and Optical Particle Sizer (OPS), and compared to breathing, speaking and coughing. Mitigation strategies such as a peak flow viral filter and a CPET facemask (to mitigate induced coughing) were tested. Results 33 healthy volunteers were recruited. Aerosol emission was highest in cough (1.61 particles/cm3/sample), followed by unfiltered peak flow (0.76 particles/cm3/sample). Filtered spirometry produced similar peak aerosol emission as talking, and addition of a viral filter to the mouthpiece reduced peak flow aerosol emission to similar levels. The filter made little difference to recorded peak flow values. FENO measurement produced negligible aerosol. Re usable CPET masks with filter reduced aerosol emission when breathing, speaking, and coughing significantly. Conclusions Compared to voluntary coughing, all lung function testing produced less aerosol. Filtered spirometry produces similar peak aerosol emission to speaking, and should not be deemed an aerosol generating procedure. The use of viral filters reduces aerosol emission in peak flow by > 10 times, and has little impact on recorded peak flow values. CPET masks are a useful option to reduce aerosol emission from induced coughing while performing spirometry.

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Section: Discussionmentioning

confidence: 99%

Risk and mitigation of aerosolisation from lung function testing: results from the AERATOR study

Sheikh

Hamilton

Nava

et al. 2021

Preprint

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“…Nine of the 18 studies provided evidence on endoscopic sinus surgery [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , six studies focused on suctioning for airway clearance [23] , [24] , [25] , [26] , [27] , [28] , four outpatient endoscopy 22 , 23 , 30 , 31 , two nasogastric tube insertion 26 , 27 and one lung function testing 32 . None of the primary studies focused on procedures or testing for dysphagia.…”

Section: Methodsmentioning

confidence: 99%

Are medical procedures that induce coughing or involve respiratory suctioning associated with increased generation of aerosols and risk of SARS-CoV-2 infection? A rapid systematic review

Wilson

Carson

Fitzgerald

et al. 2021

Journal of Hospital Infection

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The risk of transmission of SARS-CoV-2 from aerosols generated by medical procedures is a cause for concern. This rapid systematic review aimed to evaluate the evidence for aerosol production and transmission of respiratory infection associated with procedures that involve airway suctioning or induce coughing/sneezing. The review was informed by PRISMA guidelines. Searches were conducted in PubMed for studies published between 1/1/2003 and 6/10/2020. Included studies examined whether nasogastric tube insertion, lung-function tests, nasoendoscopy, dysphagia assessment or suctioning for airway clearance result in aerosol generation or transmission of SARS-CoV-2, SARS-CoV, MERS, or influenza. Risk of bias assessment assessed robustness of measurement, control for confounding and applicability to clinical practice. Eighteen primary studies and two systematic reviews were included. Three epidemiological studies found no association between nasogastric tube insertion and acquisition of respiratory infections. One simulation study found low/very low production of aerosols associated with pulmonary lung function tests. Seven simulation studies of endoscopic sinus surgery suggested significant increases in aerosols but findings were inconsistent, two clinical studies found airborne particles associated with the use of microdebriders/drills. Some simulation studies did not use robust measures to detect particles and are difficult to equate to clinical conditions. There was an absence of evidence to suggest that the procedures included in the review were associated with an increased risk of transmission of respiratory infection. In order to better target precautions to mitigate risk, more research is required to determine the characteristics of medical procedures and patients that increase the risk of transmission of SARS-CoV-2.

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“…Healthcare workers in Italy were also disproportionally affected with an approximate 20% infection rate, which is significantly higher than that of the general population 271 . Certain activities in contact with patients such as clinical lung function test, due to the emission of small droplets containing viral particles, may convey an additional risk of SARS‐CoV‐2 infection for health workers facing asymptomatic individuals during COVID‐19 due to the emission of small droplets containing viral particles 272 . The relationship between COVID‐19 severity and specific activities in the clinics or other settings that considerably increase the risk of infection warrants further and detailed investigations.…”

Section: Diet and Lifestylementioning

confidence: 99%

Risk factors for severe and critically ill COVID‐19 patients: A review

Gao

Ding

Dong

et al. 2020

Allergy

1,007

864

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The pandemic of coronavirus disease 2019 (COVID‐19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has caused an unprecedented global social and economic impact, and high numbers of deaths. Many risk factors have been identified in the progression of COVID‐19 into a severe and critical stage, including old age, male gender, underlying comorbidities such as hypertension, diabetes, obesity, chronic lung diseases, heart, liver and kidney diseases, tumors, clinically apparent immunodeficiencies, local immunodeficiencies, such as early type I interferon secretion capacity, and pregnancy. Possible complications include acute kidney injury, coagulation disorders, thoromboembolism. The development of lymphopenia and eosinopenia are laboratory indicators of COVID‐19. Laboratory parameters to monitor disease progression include lactate dehydrogenase, procalcitonin, high‐sensitivity C‐reactive protein, proinflammatory cytokines such as interleukin (IL)‐6, IL‐1β, Krebs von den Lungen‐6 (KL‐6), and ferritin. The development of a cytokine storm and extensive chest computed tomography imaging patterns are indicators of a severe disease. In addition, socioeconomic status, diet, lifestyle, geographical differences, ethnicity, exposed viral load, day of initiation of treatment, and quality of health care have been reported to influence individual outcomes. In this review, we highlight the scientific evidence on the risk factors of severity of COVID‐19.

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Small droplet emission in exhaled breath during different breathing manoeuvres: Implications for clinical lung function testing during COVID‐19

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 23 publications

References 8 publications

Risk and mitigation of aerosolisation from lung function testing: results from the AERATOR study

Risk and mitigation of aerosolisation from lung function testing: results from the AERATOR study

Are medical procedures that induce coughing or involve respiratory suctioning associated with increased generation of aerosols and risk of SARS-CoV-2 infection? A rapid systematic review

Risk factors for severe and critically ill COVID‐19 patients: A review

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