Comparison of droplet spread in standard and laminar flow operating theatres: SPRAY study group.
Aerosol-generating procedure (AGP)
COVID-19
Droplets
Fluorescein
Image analysis
Operating theatre
Journal
The Journal of hospital infection
ISSN: 1532-2939
Titre abrégé: J Hosp Infect
Pays: England
ID NLM: 8007166
Informations de publication
Date de publication:
Apr 2021
Apr 2021
Historique:
received:
01
12
2020
revised:
20
01
2021
accepted:
26
01
2021
pubmed:
8
2
2021
medline:
13
4
2021
entrez:
7
2
2021
Statut:
ppublish
Résumé
Reducing COVID-19 transmission relies on controlling droplet and aerosol spread. Fluorescein staining reveals microscopic droplets. To compare the droplet spread in non-laminar and laminar air flow operating theatres. A 'cough-generator' was fixed to a theatre trolley at 45°. Fluorescein-stained 'secretions' were projected on to a series of calibrated targets. These were photographed under UV light and 'source detection' software measured droplet splatter size and distance. The smallest droplet detected was ∼120 μm and the largest ∼24,000 μm. An average of 25,862 spots was detected in the non-laminar theatre, compared with 11,430 in the laminar theatre (56% reduction). The laminar air flow mainly affected the smaller droplets (<1000 μm). The surface area covered with droplets was: 6% at 50 cm, 1% at 2 m, and 0.5% at 3 m in the non-laminar air flow; and 3%, 0.5%, and 0.2% in the laminar air flow, respectively. Accurate mapping of droplet spread in clinical environments is possible using fluorescein staining and image analysis. The laminar air flow affected the smaller droplets but had limited effect on larger droplets in our 'aerosol-generating procedure' cough model. Our results indicate that the laminar air flow theatre requires similar post-surgery cleaning to the non-laminar, and staff should consider full personal protective equipment for medium- and high-risk patients.
Sections du résumé
BACKGROUND
BACKGROUND
Reducing COVID-19 transmission relies on controlling droplet and aerosol spread. Fluorescein staining reveals microscopic droplets.
AIM
OBJECTIVE
To compare the droplet spread in non-laminar and laminar air flow operating theatres.
METHODS
METHODS
A 'cough-generator' was fixed to a theatre trolley at 45°. Fluorescein-stained 'secretions' were projected on to a series of calibrated targets. These were photographed under UV light and 'source detection' software measured droplet splatter size and distance.
FINDINGS
RESULTS
The smallest droplet detected was ∼120 μm and the largest ∼24,000 μm. An average of 25,862 spots was detected in the non-laminar theatre, compared with 11,430 in the laminar theatre (56% reduction). The laminar air flow mainly affected the smaller droplets (<1000 μm). The surface area covered with droplets was: 6% at 50 cm, 1% at 2 m, and 0.5% at 3 m in the non-laminar air flow; and 3%, 0.5%, and 0.2% in the laminar air flow, respectively.
CONCLUSION
CONCLUSIONS
Accurate mapping of droplet spread in clinical environments is possible using fluorescein staining and image analysis. The laminar air flow affected the smaller droplets but had limited effect on larger droplets in our 'aerosol-generating procedure' cough model. Our results indicate that the laminar air flow theatre requires similar post-surgery cleaning to the non-laminar, and staff should consider full personal protective equipment for medium- and high-risk patients.
Identifiants
pubmed: 33549768
pii: S0195-6701(21)00044-X
doi: 10.1016/j.jhin.2021.01.026
pmc: PMC7860961
pii:
doi:
Substances chimiques
Aerosols
0
Types de publication
Comparative Study
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
194-200Subventions
Organisme : Medical Research Council
ID : MR/K002597/1
Pays : United Kingdom
Informations de copyright
Copyright © 2021 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
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