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Research article
Jonas Weber
Universitatsklinikum Freiburg Klinik fur Anasthesiologie und Intensivmedizin
Corresponding Author
ORCiD: https://orcid.org/0000-0002-3485-486X
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Background In obese patients, high closing capacity and low functional residual capacity increase the risk for expiratory alveolar collapse. Constant expiratory flow, as provided by the new flow-controlled ventilation (FCV) mode, was shown to improve lung recruitment. We hypothesized that lung aeration and respiratory mechanics improve in obese patients during FCV. Methods We compared FCV and volume-controlled (VCV) ventilation in 23 obese patients in a randomized cross-over setting. Starting with baseline measurements, ventilation settings were kept identical except for the ventilation mode related differences (VCV: inspiration to expiration ratio 1:2 with passive expiration, FCV: inspiration to expiration ratio 1:1 with active, linearized expiration). Primary endpoint of the study was the change of end-expiratory lung volume compared to baseline ventilation. Secondary endpoints were the change of mean lung volume, respiratory mechanics and hemodynamic variables. Results The loss of end-expiratory lung volume and mean lung volume compared to baseline was lower during FCV compared to VCV (end-expiratory lung volume: FCV, -126 ± 207 ml; VCV, -316 ± 254 ml; p < 0.001, mean lung volume: FCV, -108.2 ± 198.6 ml; VCV, -315.8 ± 252.1 ml; p < 0.001) and at comparable plateau pressure (baseline, 19.6 ± 3.7; VCV, 20.2 ± 3.4; FCV, 20.2 ± 3.8 cmH2O; p = 0.441), mean tracheal pressure was higher (baseline, 13.1 ± 1.1; VCV, 12.9 ±1.2; FCV, 14.8 ± 2.2 cmH2O; p < 0.001). All other respiratory and hemodynamic variables were comparable between the ventilation modes. Conclusions This study demonstrates that, compared to VCV, FCV improves regional ventilation distribution of the lung at comparable PEEP, tidal volume, PPlat and ventilation frequency. The increase in end-expiratory lung volume during FCV was probably caused by the increased mean tracheal pressure which can be attributed to the linearized expiratory pressure decline.
Keywords
Mechanical ventilation, Obesity, Flow-controlled ventilation, Ventilation modes: pressure waveform
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View the published article at BMC Anesthesiology.
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On 16 Jan, 2020
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On 15 Jan, 2020
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Editorial decision: Minor revision
On 01 Jan, 2020
Editor assigned
On 22 Dec, 2019
Submission checks complete
On 21 Dec, 2019
Editor invited
On 21 Dec, 2019
No comments provided
Editorial decision: Major revision
On 15 Dec, 2019
Review #2 received
Received 30 Nov, 2019
Reviewer #2 agreed
On 23 Nov, 2019
Review #1 received
Received 22 Nov, 2019
Editor assigned
On 21 Nov, 2019
Reviewers invited
Invitations sent on 21 Nov, 2019
Reviewer #1 agreed
On 21 Nov, 2019
Submission checks complete
On 20 Nov, 2019
Editor invited
On 20 Nov, 2019
No comments provided
Editorial decision: Major revision
On 22 Oct, 2019
Review #2 received
Received 20 Oct, 2019
Reviewer #2 agreed
On 25 Aug, 2019
Review #1 received
Received 19 Aug, 2019
Reviewer #1 agreed
On 02 Aug, 2019
Reviewers invited
Invitations sent on 12 Jul, 2019
Submission checks complete
On 11 Jul, 2019
Editor assigned
On 11 Jul, 2019
Editor invited
On 10 Jul, 2019
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On 02 Jul, 2019
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Subject Areas
Anesthesiology & Pain Medicine
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See the published version of this preprint at BMC Anesthesiology.
This is a preprint, 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 article
Jonas Weber
Universitatsklinikum Freiburg Klinik fur Anasthesiologie und Intensivmedizin
Corresponding Author
ORCiD: https://orcid.org/0000-0002-3485-486X
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: Published
View the published article at BMC Anesthesiology.
Version 4
Posted 17 Jan, 2020
No community comments so far
Editorial decision: Accept
On 16 Jan, 2020
Editor assigned
On 15 Jan, 2020
Submission checks complete
On 14 Jan, 2020
Editor invited
On 14 Jan, 2020
No comments provided
Editorial decision: Minor revision
On 01 Jan, 2020
Editor assigned
On 22 Dec, 2019
Submission checks complete
On 21 Dec, 2019
Editor invited
On 21 Dec, 2019
No comments provided
Editorial decision: Major revision
On 15 Dec, 2019
Review #2 received
Received 30 Nov, 2019
Reviewer #2 agreed
On 23 Nov, 2019
Review #1 received
Received 22 Nov, 2019
Editor assigned
On 21 Nov, 2019
Reviewers invited
Invitations sent on 21 Nov, 2019
Reviewer #1 agreed
On 21 Nov, 2019
Submission checks complete
On 20 Nov, 2019
Editor invited
On 20 Nov, 2019
No comments provided
Editorial decision: Major revision
On 22 Oct, 2019
Review #2 received
Received 20 Oct, 2019
Reviewer #2 agreed
On 25 Aug, 2019
Review #1 received
Received 19 Aug, 2019
Reviewer #1 agreed
On 02 Aug, 2019
Reviewers invited
Invitations sent on 12 Jul, 2019
Submission checks complete
On 11 Jul, 2019
Editor assigned
On 11 Jul, 2019
Editor invited
On 10 Jul, 2019
First submitted
On 02 Jul, 2019
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Anesthesiology & Pain Medicine
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published article at BMC Anesthesiology.
Background In obese patients, high closing capacity and low functional residual capacity increase the risk for expiratory alveolar collapse. Constant expiratory flow, as provided by the new flow-controlled ventilation (FCV) mode, was shown to improve lung recruitment. We hypothesized that lung aeration and respiratory mechanics improve in obese patients during FCV. Methods We compared FCV and volume-controlled (VCV) ventilation in 23 obese patients in a randomized cross-over setting. Starting with baseline measurements, ventilation settings were kept identical except for the ventilation mode related differences (VCV: inspiration to expiration ratio 1:2 with passive expiration, FCV: inspiration to expiration ratio 1:1 with active, linearized expiration). Primary endpoint of the study was the change of end-expiratory lung volume compared to baseline ventilation. Secondary endpoints were the change of mean lung volume, respiratory mechanics and hemodynamic variables. Results The loss of end-expiratory lung volume and mean lung volume compared to baseline was lower during FCV compared to VCV (end-expiratory lung volume: FCV, -126 ± 207 ml; VCV, -316 ± 254 ml; p < 0.001, mean lung volume: FCV, -108.2 ± 198.6 ml; VCV, -315.8 ± 252.1 ml; p < 0.001) and at comparable plateau pressure (baseline, 19.6 ± 3.7; VCV, 20.2 ± 3.4; FCV, 20.2 ± 3.8 cmH2O; p = 0.441), mean tracheal pressure was higher (baseline, 13.1 ± 1.1; VCV, 12.9 ±1.2; FCV, 14.8 ± 2.2 cmH2O; p < 0.001). All other respiratory and hemodynamic variables were comparable between the ventilation modes. Conclusions This study demonstrates that, compared to VCV, FCV improves regional ventilation distribution of the lung at comparable PEEP, tidal volume, PPlat and ventilation frequency. The increase in end-expiratory lung volume during FCV was probably caused by the increased mean tracheal pressure which can be attributed to the linearized expiratory pressure decline.
Figure 1
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Figure 4
Figure 5
Figure 6
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