Exhalation Spreading During Nasal High-Flow Therapy at Different Flow Rates.
Crit Care Med
; 49(7): e693-e700, 2021 07 01.
Article
in English
| MEDLINE | ID: covidwho-1276256
ABSTRACT
OBJECTIVES:
Severe acute respiratory syndrome coronavirus 2 is transmitted through aerosols and droplets. Nasal high-flow therapy could possibly increase the spreading of exhalates from patients. The aim of this study is to investigate whether nasal high-flow therapy affects the range of the expiratory plume compared with spontaneous breathing.DESIGN:
Interventional experiment on single breaths of a healthy volunteer.SETTING:
Research laboratory at the Bauhaus-University Weimar.SUBJECTS:
A male subject.INTERVENTIONS:
Videos and images from a schlieren optical system were analyzed during spontaneous breathing and different nasal high-flow rates. MEASUREMENTS AND MAINRESULTS:
The maximal exhalation spread was 0.99, 2.18, 2.92, and 4.1 m during spontaneous breathing, nasal high-flow of 20 L/min, nasal high-flow of 40 L/min, and nasal high-flow of 60 L/min, respectively. Spreading of the expiratory plume in the sagittal plane can completely be blocked with a surgical mask.CONCLUSIONS:
Nasal high-flow therapy increases the range of the expiratory air up to more than 4 meters. The risk to pick up infectious particles could be increased within this range. Attachment of a surgical mask over the nasal high-flow cannula blocks the expiratory airstream.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Oxygen Inhalation Therapy
/
Pulmonary Ventilation
/
Exhalation
/
Cannula
Type of study:
Prognostic study
Limits:
Adult
/
Humans
/
Male
Language:
English
Journal:
Crit Care Med
Year:
2021
Document Type:
Article
Affiliation country:
Ccm.0000000000005009
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