A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE)
A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE)
Clinical observations suggest that compared with standard apnoeic oxygenation, transnasal humidified rapid-insufflation ventilatory exchange using high-flow nasal oxygenation reduces the rate of carbon dioxide accumulation in patients who are anaesthetised and apnoeic. This suggests that active gas exchange takes place, but the mechanisms by which it may occur have not been described. We used three laboratory airway models to investigate mechanisms of carbon dioxide clearance in apnoeic patients. We determined flow patterns using particle image velocimetry in a two-dimensional model using particle-seeded fluorescent solution; visualised gas clearance in a three-dimensional printed trachea model in air; and measured intra-tracheal turbulence levels and carbon dioxide clearance rates using a three-dimensional printed model in air mounted on a lung simulator. Cardiogenic oscillations were simulated in all experiments. The visualisation experiments indicated that gaseous mixing was occurring in the trachea. With no cardiogenic oscillations applied, mean (SD) carbon dioxide clearance increased from 0.29 (0.04) ml.min-1 to 1.34 (0.14) ml.min-1 as the transnasal humidified rapid-insufflation ventilatory exchange flow rate was increased from 20 l.min-1 to 70 l.min-1 (p = 0.0001). With a cardiogenic oscillation of 20 ml.beat-1 applied, carbon dioxide clearance increased from 11.9 (0.50) ml.min-1 to 17.4 (1.2) ml.min-1 as the transnasal humidified rapid-insufflation ventilatory exchange flow rate was increased from 20 l.min-1 to 70 l.min-1 (p = 0.0014). These findings suggest that enhanced carbon dioxide clearance observed under apnoeic conditions with transnasal humidified rapid-insufflation ventilatory exchange, as compared with classical apnoeic oxygenation, may be explained by an interaction between entrained and highly turbulent supraglottic flow vortices created by high-flow nasal oxygen and cardiogenic oscillations.
Administration, Intranasal, Airway Management, Apnea/metabolism, Carbon Dioxide/metabolism, Humans, Insufflation, Metabolic Clearance Rate, Oxygen/administration & dosage, Pulmonary Gas Exchange
441-449
Hermez, L.A.
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Spence, C.J.
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Payton, M.J.
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Nouraei, S.A.R.
f09047ee-ed51-495d-a257-11837e74c2b3
Patel, A.
05f1956d-b07c-45f0-9283-3e461d8a12fa
Barnes, T.H.
324163e8-0056-4ad0-8c23-51a36674d209
April 2019
Hermez, L.A.
bd3b79f9-dc89-4660-8c94-709dd8516022
Spence, C.J.
9b08f61f-36c9-4e4e-8a89-16da83c8ad60
Payton, M.J.
cbb6b0a6-acee-4032-9536-74c450c19544
Nouraei, S.A.R.
f09047ee-ed51-495d-a257-11837e74c2b3
Patel, A.
05f1956d-b07c-45f0-9283-3e461d8a12fa
Barnes, T.H.
324163e8-0056-4ad0-8c23-51a36674d209
Hermez, L.A., Spence, C.J., Payton, M.J., Nouraei, S.A.R., Patel, A. and Barnes, T.H.
(2019)
A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE).
Anaesthesia, 74 (4), .
(doi:10.1111/anae.14541).
Abstract
Clinical observations suggest that compared with standard apnoeic oxygenation, transnasal humidified rapid-insufflation ventilatory exchange using high-flow nasal oxygenation reduces the rate of carbon dioxide accumulation in patients who are anaesthetised and apnoeic. This suggests that active gas exchange takes place, but the mechanisms by which it may occur have not been described. We used three laboratory airway models to investigate mechanisms of carbon dioxide clearance in apnoeic patients. We determined flow patterns using particle image velocimetry in a two-dimensional model using particle-seeded fluorescent solution; visualised gas clearance in a three-dimensional printed trachea model in air; and measured intra-tracheal turbulence levels and carbon dioxide clearance rates using a three-dimensional printed model in air mounted on a lung simulator. Cardiogenic oscillations were simulated in all experiments. The visualisation experiments indicated that gaseous mixing was occurring in the trachea. With no cardiogenic oscillations applied, mean (SD) carbon dioxide clearance increased from 0.29 (0.04) ml.min-1 to 1.34 (0.14) ml.min-1 as the transnasal humidified rapid-insufflation ventilatory exchange flow rate was increased from 20 l.min-1 to 70 l.min-1 (p = 0.0001). With a cardiogenic oscillation of 20 ml.beat-1 applied, carbon dioxide clearance increased from 11.9 (0.50) ml.min-1 to 17.4 (1.2) ml.min-1 as the transnasal humidified rapid-insufflation ventilatory exchange flow rate was increased from 20 l.min-1 to 70 l.min-1 (p = 0.0014). These findings suggest that enhanced carbon dioxide clearance observed under apnoeic conditions with transnasal humidified rapid-insufflation ventilatory exchange, as compared with classical apnoeic oxygenation, may be explained by an interaction between entrained and highly turbulent supraglottic flow vortices created by high-flow nasal oxygen and cardiogenic oscillations.
More information
Accepted/In Press date: 20 November 2018
e-pub ahead of print date: 15 February 2019
Published date: April 2019
Keywords:
Administration, Intranasal, Airway Management, Apnea/metabolism, Carbon Dioxide/metabolism, Humans, Insufflation, Metabolic Clearance Rate, Oxygen/administration & dosage, Pulmonary Gas Exchange
Identifiers
Local EPrints ID: 438310
URI: http://eprints.soton.ac.uk/id/eprint/438310
ISSN: 0003-2409
PURE UUID: 888ac5c5-8df9-413a-9a6a-8a1d8a24a2ce
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Date deposited: 04 Mar 2020 17:34
Last modified: 16 Mar 2024 06:47
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Contributors
Author:
L.A. Hermez
Author:
C.J. Spence
Author:
M.J. Payton
Author:
S.A.R. Nouraei
Author:
A. Patel
Author:
T.H. Barnes
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