A self-regulated expiratory flow device for mechanical ventilation: a bench study

Abstract Introduction Unregulated expiratory flow may contribute to ventilator-induced lung injury. The amount of energy dissipated into the lungs with tidal mechanical ventilation may be used to quantify potentially injurious ventilation. Previously reported devices for variable expiratory flow reg...

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Main Authors: Lianye Yang, Ubbo F. Wiersema, Shailesh Bihari, Roy Broughton, Andy Roberts, Nigel Kelley, Mark McEwen
Format: Article
Language:English
Published: SpringerOpen 2024-10-01
Series:Intensive Care Medicine Experimental
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Online Access:https://doi.org/10.1186/s40635-024-00681-0
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author Lianye Yang
Ubbo F. Wiersema
Shailesh Bihari
Roy Broughton
Andy Roberts
Nigel Kelley
Mark McEwen
author_facet Lianye Yang
Ubbo F. Wiersema
Shailesh Bihari
Roy Broughton
Andy Roberts
Nigel Kelley
Mark McEwen
author_sort Lianye Yang
collection DOAJ
description Abstract Introduction Unregulated expiratory flow may contribute to ventilator-induced lung injury. The amount of energy dissipated into the lungs with tidal mechanical ventilation may be used to quantify potentially injurious ventilation. Previously reported devices for variable expiratory flow regulation (FLEX) require, either computer-controlled feedback, or an initial expiratory flow trigger. In this bench study we present a novel passive expiratory flow regulation device. Methods The device was tested using a commercially available mechanical ventilator with a range of settings (tidal volume 420 ml and 630 ml, max. inspiratory flow rate 30 L/min and 50 L/min, respiratory rate 10 min−1, positive end-expiratory pressure 5 cmH2O), and a test lung with six different combinations of compliance and resistance settings. The effectiveness of the device was evaluated for reduction in peak expiratory flow, expiratory time, mean airway pressure, and the reduction of tidal dissipated energy (measured as the area within the airway pressure–volume loop). Results Maximal and minimal reduction in peak expiratory flow was from 97.18 ± 0.41 L/min to 25.82 ± 0.07 L/min (p < 0.001), and from 44.11 ± 0.42 L/min to 26.30 ± 0.06 L/min, respectively. Maximal prolongation in expiratory time was recorded from 1.53 ± 0.06 s to 3.64 ± 0.21 s (p < 0.001). As a result of the extended expiration, the maximal decrease in I:E ratio was from 1:1.15 ± 0.03 to 1:2.45 ± 0.01 (p < 0.001). The greatest increase in mean airway pressure was from 10.04 ± 0.03 cmH2O to 17.33 ± 0.03 cmH2O. Dissipated energy was significantly reduced with the device under all test conditions (p < 0.001). The greatest reduction in dissipated energy was from 1.74 ± 0.00 J to 0.84 ± 0.00 J per breath. The least reduction in dissipated energy was from 0.30 ± 0.00 J to 0.16 ± 0.00 J per breath. The greatest and least percentage reduction in dissipated energy was 68% and 33%, respectively. Conclusions The device bench tested in this study demonstrated a significant reduction in peak expiratory flow rate and dissipated energy, compared to ventilation with unregulated expiratory flow. Application of the device warrants further experimental and clinical evaluation.
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spelling doaj-art-5aaa0197b2804d3cb80e0f71da45ecba2025-08-20T02:17:38ZengSpringerOpenIntensive Care Medicine Experimental2197-425X2024-10-0112111010.1186/s40635-024-00681-0A self-regulated expiratory flow device for mechanical ventilation: a bench studyLianye Yang0Ubbo F. Wiersema1Shailesh Bihari2Roy Broughton3Andy Roberts4Nigel Kelley5Mark McEwen6Biomedical Engineering Department, Flinders Medical Centre, South Adelaide Local Health NetworkIntensive and Critical Care Unit, Flinders Medical Centre, South Adelaide Local Health NetworkIntensive and Critical Care Unit, Flinders Medical Centre, South Adelaide Local Health NetworkBiomedical Engineering Department, Flinders Medical Centre, South Adelaide Local Health NetworkBiomedical Engineering Department, Flinders Medical Centre, South Adelaide Local Health NetworkBiomedical Engineering Department, Flinders Medical Centre, South Adelaide Local Health NetworkBiomedical Engineering Department, Flinders Medical Centre, South Adelaide Local Health NetworkAbstract Introduction Unregulated expiratory flow may contribute to ventilator-induced lung injury. The amount of energy dissipated into the lungs with tidal mechanical ventilation may be used to quantify potentially injurious ventilation. Previously reported devices for variable expiratory flow regulation (FLEX) require, either computer-controlled feedback, or an initial expiratory flow trigger. In this bench study we present a novel passive expiratory flow regulation device. Methods The device was tested using a commercially available mechanical ventilator with a range of settings (tidal volume 420 ml and 630 ml, max. inspiratory flow rate 30 L/min and 50 L/min, respiratory rate 10 min−1, positive end-expiratory pressure 5 cmH2O), and a test lung with six different combinations of compliance and resistance settings. The effectiveness of the device was evaluated for reduction in peak expiratory flow, expiratory time, mean airway pressure, and the reduction of tidal dissipated energy (measured as the area within the airway pressure–volume loop). Results Maximal and minimal reduction in peak expiratory flow was from 97.18 ± 0.41 L/min to 25.82 ± 0.07 L/min (p < 0.001), and from 44.11 ± 0.42 L/min to 26.30 ± 0.06 L/min, respectively. Maximal prolongation in expiratory time was recorded from 1.53 ± 0.06 s to 3.64 ± 0.21 s (p < 0.001). As a result of the extended expiration, the maximal decrease in I:E ratio was from 1:1.15 ± 0.03 to 1:2.45 ± 0.01 (p < 0.001). The greatest increase in mean airway pressure was from 10.04 ± 0.03 cmH2O to 17.33 ± 0.03 cmH2O. Dissipated energy was significantly reduced with the device under all test conditions (p < 0.001). The greatest reduction in dissipated energy was from 1.74 ± 0.00 J to 0.84 ± 0.00 J per breath. The least reduction in dissipated energy was from 0.30 ± 0.00 J to 0.16 ± 0.00 J per breath. The greatest and least percentage reduction in dissipated energy was 68% and 33%, respectively. Conclusions The device bench tested in this study demonstrated a significant reduction in peak expiratory flow rate and dissipated energy, compared to ventilation with unregulated expiratory flow. Application of the device warrants further experimental and clinical evaluation.https://doi.org/10.1186/s40635-024-00681-0Energy dissipationExpiratory resistive loadFlow-controlled expirationMandatory ventilation
spellingShingle Lianye Yang
Ubbo F. Wiersema
Shailesh Bihari
Roy Broughton
Andy Roberts
Nigel Kelley
Mark McEwen
A self-regulated expiratory flow device for mechanical ventilation: a bench study
Intensive Care Medicine Experimental
Energy dissipation
Expiratory resistive load
Flow-controlled expiration
Mandatory ventilation
title A self-regulated expiratory flow device for mechanical ventilation: a bench study
title_full A self-regulated expiratory flow device for mechanical ventilation: a bench study
title_fullStr A self-regulated expiratory flow device for mechanical ventilation: a bench study
title_full_unstemmed A self-regulated expiratory flow device for mechanical ventilation: a bench study
title_short A self-regulated expiratory flow device for mechanical ventilation: a bench study
title_sort self regulated expiratory flow device for mechanical ventilation a bench study
topic Energy dissipation
Expiratory resistive load
Flow-controlled expiration
Mandatory ventilation
url https://doi.org/10.1186/s40635-024-00681-0
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