Flow‐controlled ventilation improves gas exchange in lung‐healthy patients— a randomized interventional cross‐over study

Weber, Jonas; Schmidt, Johannes; Straka, Leonie; Wirth, Steffen; Schumann, Stefan

doi:10.1111/aas.13526

Cited by 32 publications

(31 citation statements)

References 25 publications

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“…However, minimal and maximal airway pressure and tidal volume remained unchanged. Our results are consistent with and enlarge upon earlier findings on the implications of a linearized expiratory pressure decrease in lung-healthy patients, lung healthy pigs and a porcine lung-injury model [6][7][8][9].…”

Section: Discussionsupporting

confidence: 92%

“…We did not perform arterial blood gas analyses to examine the effects of FCV on gas exchange in our patients. In preclinical [17] and clinical studies [8], the controlled expiration improved oxygenation and CO 2 elimination. However, in contrast to other centers, placing an arterial line is not part of our standard treatment in this patient group.…”

Section: Limitations Of the Studymentioning

confidence: 98%

“…Thereby pressure increases linearly during inspiration [comparable to volume-controlled ventilation (VCV)] and decreases linearly during expiration. Recently, we demonstrated that linearizing the expiratory flow improved lung recruitment, the homogeneity of lung aeration [6,7], gas exchange [8] and further attenuated experimental lung injury [9]. Since FCV is a new emerging technique comparative clinical studies in humans, particularly in patients with impaired respiratory system mechanics, are lacking.…”

Section: Introductionmentioning

confidence: 99%

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Flow-controlled ventilation (FCV) improves regional ventilation in obese patients – a randomized controlled crossover trial

et al. 2020

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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 crossover 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 endexpiratory 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 cmH 2 O; p = 0.441), mean tracheal pressure was higher (baseline, 13.1 ± 1.1; VCV, 12.9 ± 1.2; FCV, 14.8 ± 2.2 cmH 2 O; 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, P Plat 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.

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Section: Discussionsupporting

confidence: 92%

Section: Limitations Of the Studymentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Flow-controlled ventilation (FCV) improves regional ventilation in obese patients – a randomized controlled crossover trial

et al. 2020

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Section: Discussionsupporting

confidence: 92%

Flow-controlled ventilation (FCV) improves regional ventilation in obese patients – a randomized controlled crossover trial

Weber

Straka

Borgmann

et al. 2020

Preprint

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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.

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“…We showed that compliance-guided pressure adjustment with FCV did not cause more regional overin ation of lung tissue when compared to evidence-based, low tidal volume PCV even though higher V T s were applied with FCV. Several studies report a signi cant improvement in ventilation e ciency and aeration of lung tissue when FCV is applied [12,13,14,15,16]; however, these studies did not use an individualized ventilation approach. Our study shows that normocapnia was maintained in individualized FCV despite a remarkable reduction of respiratory minute volume by 50% compared to PCV.…”

Section: Discussionmentioning

confidence: 99%

Individualized flow-controlled ventilation compared to best clinical practice pressure-controlled ventilation: a prospective randomized porcine study.

Spraider

Martini

Abram

et al. 2020

Preprint

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Background: Flow-controlled ventilation is a novel ventilation method which allows to individualize ventilation according to dynamic lung mechanic limits based on direct tracheal pressure measurement at a stable constant gas flow during inspiration and expiration. The aim of this porcine study was to compare individualized flow-controlled ventilation (FCV) and current guideline-conform pressure-controlled ventilation (PCV) in long-term ventilation.Methods: Anesthetized pigs were ventilated with either FCV or PCV over a period of ten hours with a fixed FiO2 of 0.3. FCV settings were individualized by compliance-guided positive end-expiratory pressure (PEEP) and peak pressure (Ppeak) titration. Flow was adjusted to maintain normocapnia and the inspiration to expiration ratio (I:E ratio) was set at 1:1. PCV was performed with a PEEP of 5 cm H2O and Ppeak was set to achieve a tidal volume (VT) of 7 ml/kg. The respiratory rate was adjusted to maintain normocapnia and the I:E ratio was set at 1:1.5. Repeated measurements during observation period were assessed by linear mixed-effects model.Results: In FCV (n=6) respiratory minute volume was significantly reduced (6.0 vs 12.7, MD -6.8 (-8.2 to -5.4) l/min; p<0.001) as compared to PCV (n=6). Oxygenation was improved in the FCV group (paO2 119.8 vs 96.6, MD 23.2 (9.0 to 37.5) torr; 15.97 vs 12.87, MD 3.10 (1.19 to 5.00) kPa; p=0.010) and CO2 removal was more efficient (paCO2 40.1 vs 44.9, MD -4.7 (-7.4 to -2.0) torr; 5.35 vs 5.98, MD -0.63 (-0.99 to -0.27) kPa; p=0.006). Ppeak and driving pressure were comparable in both groups, whereas PEEP was significantly lower in FCV (p=0.002). Computed tomography revealed a significant reduction in non-aerated lung tissue in individualized FCV (p=0.026) and no significant difference in overdistended lung tissue, although a significantly higher VT was applied (8.2 vs 7.6, MD 0.7 (0.2 to 1.2) ml/kg; p=0.025).Conclusion: Our long-term ventilation study demonstrates the applicability of a compliance-guided individualization of FCV settings, which resulted in significantly improved gas exchange and lung tissue aeration without signs of overinflation as compared to best clinical practice PCV.

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Flow‐controlled ventilation improves gas exchange in lung‐healthy patients— a randomized interventional cross‐over study

Abstract: This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Cited by 32 publications

References 25 publications

Flow-controlled ventilation (FCV) improves regional ventilation in obese patients – a randomized controlled crossover trial

Flow-controlled ventilation (FCV) improves regional ventilation in obese patients – a randomized controlled crossover trial

Flow-controlled ventilation (FCV) improves regional ventilation in obese patients – a randomized controlled crossover trial

Individualized flow-controlled ventilation compared to best clinical practice pressure-controlled ventilation: a prospective randomized porcine study.

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