To the Editor:
A barrier should be developed to protect medical staffs from droplets and aerosols containing SARS-CoV-2. The aerosol box [1] is one such barrier, but further improvement is required. We devised a Balloon for Aerosol Protection (BAP) that drastically decreases the risk of infection. It is an airtight protective device even when patient moves head, with built-in glove covers that a laryngoscopist can move his hands at will (ESM Figure 1).
First, we trialed the BAP with the laryngoscopist extubating the mannequin inside the sealed BAP. Before awakening from anesthesia, insert the underside of the BAP under the head and put the top side of the BAP on the mannequin. Pass the Heat and Moisture Exchanger and suction tube through the holes of the BAP and tape up the gaps. Put the necessary items, such as suction catheters, cuff syringe, surgical mask and anaesthetic mask, inside the BAP in advance. Seal BAP to the patient to almost airtight condition. The transparency and flexibility of the polyethylene bag facilitated successful suction and extubation. The patient’s respiration is maintained using an anaesthetic mask, while aerosols generated inside the BAP are removed by ordinary suction equipment inserted through the BAP (ESM Movie 1).
Second, we spread a fluorescent as pseudo droplets and aerosols inside the BAP, and confirmed isolation of the operator’s hands from the BAP chamber (ESM Movie 2).
Caveats: The completely sealed airtight condition inside the BAP might cause CO2 retention or a low O2 environment. Operators should be ready to tear off the BAP if the patients’ condition requires re-intubation or other respiratory support.
Electronic supplementary material
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Supplementary file3 Fig. S1 a-1 Extubation inside the BAP. Significant amounts of droplets and aerosols can be generated by stimulation of the patient’s cough reflex. The red circles denote floating aerosols inside the BAP. a-2 Removal of aerosols inside the BAP by suction. The arrows denote airflow by suction. a-3 Photograph showing extubation of a mannequin inside the BAP. b-1 Spraying fluorescent dye inside the BAP. b-2 No dye was deposited on the mannequin’s gloves, as seen by examination of the gloves under ultraviolet light after removal of the BAP (JPG 894 kb)
Acknowledgements
The authors thank Xiaotong Li for technical support.
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Conflict of interest
This study is supported by Konica Minolta Science and Technology Foundation.
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Reference
- 1.Canelli R, Connor CW, Gonzalez M, Nozari A, Ortega R. Barrier enclosure during endotracheal intubation. N Engl J Med. 2020 doi: 10.1056/NEJMc2007589. [DOI] [PMC free article] [PubMed] [Google Scholar]
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Supplementary Materials
Supplementary file3 Fig. S1 a-1 Extubation inside the BAP. Significant amounts of droplets and aerosols can be generated by stimulation of the patient’s cough reflex. The red circles denote floating aerosols inside the BAP. a-2 Removal of aerosols inside the BAP by suction. The arrows denote airflow by suction. a-3 Photograph showing extubation of a mannequin inside the BAP. b-1 Spraying fluorescent dye inside the BAP. b-2 No dye was deposited on the mannequin’s gloves, as seen by examination of the gloves under ultraviolet light after removal of the BAP (JPG 894 kb)