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Research
Flow of Room Air Leads to Rapid Changes in Mucociliary Transport in the Tracheal Epithelium
Stanislav Tatkov
Fisher & Paykel Healthcare
Corresponding Author
ORCiD: https://orcid.org/0000-0002-2064-0481
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This work is licensed under a CC BY 4.0 License. Read Full License
The most recent version of this article is available here.
BACKGROUND: Inspired air is heated and humidified in the nose before it reaches lower airways. This mechanism is bypassed during tracheostomy, directly exposing the lower airways to colder and drier air from the environment, which is known to have negative effects on mucociliary transport; however, little is known about how quickly mucociliary transport deteriorates. The purpose of this study was to determine the short-term effect of flowing room air on mucociliary transport in the trachea. In an ovine perfused in vitro tracheal model (N=7) the epithelium was exposed to 25 L/min of flow, heated to lamb body temperature (38 °C) and fully saturated with water vapor as the control, followed by room air (22 °C and 50% relative humidity) for a short duration, until mucociliary transport had visually stopped. Mucus transport velocity (MTV) and cilia beat frequency (CBF), as well as the area of the surface with beating cilia, were continuously measured with video-microscopy.
RESULTS: Exposing the tracheal epithelium to air heated to body temperature and fully humidified resulted in stable MTV 9.5 ± 1.1 mm/min and CBF 13.4 ± 0.6 Hz. When exposed to the flow of room air, MTV slowed down to 0.1 ± 0.1 mm/min in 2.0 ± 0.4 seconds followed by a decrease in CBF to 6.7 ± 1.9 Hz, after 2.3 ± 0.8 second. Both MTV and CBF recovered to their initial state when heated and humidified air-flow was re-introduced.
CONCLUSIONS: This study demonstrates mucociliary transport can deteriorate within seconds of exposing the tracheal epithelium to flowing room air. The reduction in MTV precedes slowing of CBF. Their relationship is non-linear and a minimum CBF of approximately 6 Hz is required for MTV > 0. Clinically these findings indicate a potential rapid detrimental effect of breathing with non-humidified air via bypassed upper airways.
Keywords
mucociliary transport, cilia, mucus, video-microscopy, airway epithelium, humidity
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- Additionalfile.docx
- AdditionalfileVideo1.mp4
Video-microscopy recording of mucociliary transport in vitro (left) when exposed to room air (22 °C and 50 % relative humidity) at t=4-12 seconds and t= 29-34 seconds and returned to body temperature and fully saturated with water vapor (38 °C and 100% relative humidity) in between. The recording demonstrates repeated exposure of room air on the tracheal epithelium. The corresponding mucociliary transport measurements of cilia beat frequency (CBF) and mucus transport velocity (MTV) are plotted on the right.
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CURRENT STATUS: Under Review
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Editor assigned
On 18 Jan, 2021
Submission checks complete
On 18 Jan, 2021
Editor invited
On 18 Jan, 2021
Version (no preprint)
Posted 15 Jan, 2021
Editorial decision: Minor revision
On 15 Jan, 2021
Review #1 received
Received 27 Dec, 2020
Reviewer #1 agreed
On 26 Dec, 2020
Reviewers invited
Invitations sent on 19 Dec, 2020
Editor assigned
On 13 Dec, 2020
Submission checks complete
On 13 Dec, 2020
Editor invited
On 13 Dec, 2020
This version was not preprinted
Version 1
Posted 07 Oct, 2020
No comments provided
Editorial decision: Major revision
On 17 Nov, 2020
Review #1 received
Received 27 Oct, 2020
Reviewer #1 agreed
On 09 Oct, 2020
Reviewers invited
Invitations sent on 08 Oct, 2020
Editor assigned
On 21 Sep, 2020
First submitted
On 20 Sep, 2020
Submission checks complete
On 20 Sep, 2020
Editor invited
On 20 Sep, 2020
Metrics
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Subject Areas
Critical Care & Emergency Medicine
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This preprint is under consideration at Intensive Care Medicine Experimental. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Flow of Room Air Leads to Rapid Changes in Mucociliary Transport in the Tracheal Epithelium
Stanislav Tatkov
Fisher & Paykel Healthcare
Corresponding Author
ORCiD: https://orcid.org/0000-0002-2064-0481
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
No community comments so far
Editor assigned
On 18 Jan, 2021
Submission checks complete
On 18 Jan, 2021
Editor invited
On 18 Jan, 2021
Version (no preprint)
Posted 15 Jan, 2021
Editorial decision: Minor revision
On 15 Jan, 2021
Review #1 received
Received 27 Dec, 2020
Reviewer #1 agreed
On 26 Dec, 2020
Reviewers invited
Invitations sent on 19 Dec, 2020
Editor assigned
On 13 Dec, 2020
Submission checks complete
On 13 Dec, 2020
Editor invited
On 13 Dec, 2020
This version was not preprinted
Version 1
Posted 07 Oct, 2020
No comments provided
Editorial decision: Major revision
On 17 Nov, 2020
Review #1 received
Received 27 Oct, 2020
Reviewer #1 agreed
On 09 Oct, 2020
Reviewers invited
Invitations sent on 08 Oct, 2020
Editor assigned
On 21 Sep, 2020
First submitted
On 20 Sep, 2020
Submission checks complete
On 20 Sep, 2020
Editor invited
On 20 Sep, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Critical Care & Emergency Medicine
License:
This work is licensed under a CC BY 4.0 License. Read Full License
The most recent version of this article is available here.
BACKGROUND: Inspired air is heated and humidified in the nose before it reaches lower airways. This mechanism is bypassed during tracheostomy, directly exposing the lower airways to colder and drier air from the environment, which is known to have negative effects on mucociliary transport; however, little is known about how quickly mucociliary transport deteriorates. The purpose of this study was to determine the short-term effect of flowing room air on mucociliary transport in the trachea. In an ovine perfused in vitro tracheal model (N=7) the epithelium was exposed to 25 L/min of flow, heated to lamb body temperature (38 °C) and fully saturated with water vapor as the control, followed by room air (22 °C and 50% relative humidity) for a short duration, until mucociliary transport had visually stopped. Mucus transport velocity (MTV) and cilia beat frequency (CBF), as well as the area of the surface with beating cilia, were continuously measured with video-microscopy.
RESULTS: Exposing the tracheal epithelium to air heated to body temperature and fully humidified resulted in stable MTV 9.5 ± 1.1 mm/min and CBF 13.4 ± 0.6 Hz. When exposed to the flow of room air, MTV slowed down to 0.1 ± 0.1 mm/min in 2.0 ± 0.4 seconds followed by a decrease in CBF to 6.7 ± 1.9 Hz, after 2.3 ± 0.8 second. Both MTV and CBF recovered to their initial state when heated and humidified air-flow was re-introduced.
CONCLUSIONS: This study demonstrates mucociliary transport can deteriorate within seconds of exposing the tracheal epithelium to flowing room air. The reduction in MTV precedes slowing of CBF. Their relationship is non-linear and a minimum CBF of approximately 6 Hz is required for MTV > 0. Clinically these findings indicate a potential rapid detrimental effect of breathing with non-humidified air via bypassed upper airways.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7