A high-flow nasal cannula system with relatively low flow effectively washes out CO2 from the anatomical dead space in a sophisticated respiratory model made by a 3D printer
Although clinical studies of the high-flow nasal cannula (HFNC) and its effect on positive end-expiratory pressure (PEEP) have been done, the washout effect has not been well evaluated. Therefore, we made an experimental respiratory model to evaluate the respiratory physiological effect of HFNC.
An airway model was made by a 3D printer using the craniocervical 3D-CT data of a healthy 32-year-old male. CO2was infused into four respiratory lung models (normal-lung, open- and closed-mouth models; restrictive- and obstructive-lung, open-mouth models) to maintain the partial pressure of end-tidal CO2(PETCO2) at 40 mmHg. HFNC flow was changed from 10 to 60 L/min. Capnograms were recorded at the upper pharynx, oral cavity, subglottic, and inlet sites of each lung model.
With the normal-lung, open-mouth model, 10 L/min of HFNC flow decreased the subglottic PETCO2to 30 mmHg. Increasing the HFNC flow did not further decrease the subglottic PETCO2. With the normal-lung, closed-mouth model, HFNC flow of 40 L/min was required to decrease the PETCO2at all sites. Subglottic PETCO2reached 30 mmHg with an HFNC flow of 60 L/min. In the obstructive-lung, open-mouth model, PETCO2at all sites had the same trend as in the normal-lung, open-mouth model. In the restrictive-lung, open-mouth model, 20 L/min of HFNC flow decreased the subglottic PETCO2to 25 mmHg, and it did not decrease further. As HFNC flow was increased, PEEP up to 7 cmH2O was gradually generated in the open-mouth models and up to 17 cmH2O in the normal-lung, closed-mouth model.
The washout effect of the HFNC was effective with relatively low flow in the open-mouth models. The closed-mouth model needed more flow to generate a washout effect. Therefore, HFNC flow should be considered based on the need for the washout effect or PEEP.
Pharmacology, Toxicology and Pharmaceutical Science
1
3%
Nursing and Health Professions
1
3%
Neuroscience
1
3%
Other
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Unknown
15
44%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 13. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 21 March 2019.
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#2,651,796
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Outputs from Intensive Care Medicine Experimental
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#55,595
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Outputs of similar age from Intensive Care Medicine Experimental
#6
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