Positive end-expiratory pressure and prone position alter the capacity of force generation from diaphragm in acute respiratory distress syndrome: an animal experiment

Firstiogusran, Andi Muhammad Fadlillah; Yoshida, Toyohiko; Hashimoto, Haruka; Iwata, Hideyuki; Fujino, Yuji

doi:10.1186/s12871-022-01921-0

Cited by 4 publications

(3 citation statements)

References 25 publications

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“…Indeed, a higher lung volume is known to reduce the diaphragm length, resulting in less force generation from the muscle [ 25 ]. In a rabbit ARDS model, the capacity of the force generation of the diaphragm (transdiaphragmatic pressure following bilateral phrenic nerve stimulation) decreased by increasing the PEEP, and the effect was mediated by alteration in the end-expiratory lung volume (as evidenced by CT) [ 26 ].…”

Section: Discussionmentioning

confidence: 99%

The Effects of Positive End Expiratory Pressure and Lung Volume on Diaphragm Thickness and Thickening

et al. 2023

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Introduction: Diaphragm dysfunction is common in patients undergoing mechanical ventilation. The application of positive end-expiratory pressure (PEEP) and the varying end-expiratory lung volume cause changes in diaphragm geometry. We aimed to assess the impact of the level of PEEP and lung inflation on diaphragm thickness, thickening fraction and displacement. Methods: An observational study in a mixed medical and surgical ICU was conducted. The patients underwent a PEEP-titration trial with the application of three random levels of PEEP: 0 cmH2O (PEEP0), 8 cmH2O (PEEP8) and 15 cmH2O (PEEP15). At each step, the indices of respiratory effort were assessed, together with arterial blood and diaphragm ultrasound; end-expiratory lung volume was measured. Results: 14 patients were enrolled. The tidal volume, diaphragm displacement and thickening fraction were significantly lower with higher levels of PEEP, while both the expiratory and inspiratory thickness increased with higher PEEP levels. The inspiratory effort, as evaluated by the esophageal pressure swing, was unchanged. Both the diaphragm thickening fraction and displacement were significantly correlated with inspiratory effort in the whole dataset. For both measurements, the correlation was stronger at lower levels of PEEP. The difference in the diaphragm thickening fraction during tidal breathing between PEEP 15 and PEEP 0 was negatively related to the change in the functional residual capacity and the change in alveolar dead space. Conclusions: Different levels of PEEP significantly modified the diaphragmatic thickness and thickening fraction, showing a PEEP-induced decrease in the diaphragm contractile efficiency. When using ultrasound to assess diaphragm size and function, the potential effect of lung inflation should be taken into account.

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Section: Discussionmentioning

confidence: 99%

The Effects of Positive End Expiratory Pressure and Lung Volume on Diaphragm Thickness and Thickening

et al. 2023

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“…It is known that the lung volume state and PEEP level affect the neuromuscular efficiency and geometry of the diaphragm, affecting the generation of transdiaphragmatic pressure, especially in healthy individuals [ 13 ]. High lung volume states associated with high PEEP settings limit the ability of the diaphragm to produce large drops in airway pressure and high transpulmonary driving pressure [ 28 ]. Importantly, we assessed the EDR using the ΔPes, which is a clinically more important variable in P-SILI development and lung protective ventilation strategies than what has been shown for the transdiaphragmatic pressure (Pdi), which is used to assess the neuromuscular efficiency of the diaphragm.…”

Section: Discussionmentioning

confidence: 99%

Positive end-expiratory pressure limits inspiratory effort through modulation of the effort-to-drive ratio: an experimental crossover study

Widing,

Pellegrini,

Chiodaroli

et al. 2024

ICMx

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Background How assisted spontaneous breathing should be used during acute respiratory distress syndrome is questioned. Recent evidence suggests that high positive end-expiratory pressure (PEEP) may limit the risk of patient self-inflicted lung injury (P-SILI). The aim of this study was to assess the effects of PEEP on esophageal pressure swings, inspiratory drive, and the neuromuscular efficiency of ventilation. We hypothesized that high PEEP would reduce esophageal pressure swings, regardless of inspiratory drive changes, by modulating the effort-to-drive ratio (EDR). This was tested retrospectively in an experimental animal crossover study. Anesthetized pigs (n = 15) were subjected to mild to moderate lung injury and different PEEP levels were applied, changing PEEP from 0 to 15 cmH2O and back to 0 cmH2O in steps of 3 cmH2O. Airway pressure, esophageal pressure (Pes), and electric activity of the diaphragm (Edi) were collected. The EDR was calculated as the tidal change in Pes divided by the tidal change in Edi. Statistical differences were tested using the Wilcoxon signed-rank test. Results Inspiratory esophageal pressure swings decreased from − 4.2 ± 3.1 cmH2O to − 1.9 ± 1.5 cmH2O (p < 0.01), and the mean EDR fell from − 1.12 ± 1.05 cmH2O/µV to − 0.24 ± 0.20 (p < 0.01) as PEEP was increased from 0 to 15 cmH2O. The EDR was significantly correlated to the PEEP level (rs = 0.35, p < 0.01). Conclusions Higher PEEP limits inspiratory effort by modulating the EDR of the respiratory system. These findings indicate that PEEP may be used in titration of the spontaneous impact on ventilation and in P-SILI risk reduction, potentially facilitating safe assisted spontaneous breathing. Similarly, ventilation may be shifted from highly spontaneous to predominantly controlled ventilation using PEEP. These findings need to be confirmed in clinical settings.

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“…Furthermore, the pressure and gas flow are affected by many respiratory factors. For example, PEEP affects the lung compliance, strain distribution pattern [ 63 ], and intensity of the spontaneous breathing [ 64 , 65 ]. Moreover, when higher chest wall compliance is assumed, a greater part of the patient’s inspiratory effort is used to move the chest wall than for lung inflation.…”

Section: Discussionmentioning

confidence: 99%

Endotracheal tube, by the venturi effect, reduces the efficacy of increasing inlet pressure in improving pendelluft

Takahashi,

Toyama,

Ejima

et al. 2023

PLoS ONE

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In mechanically ventilated severe acute respiratory distress syndrome patients, spontaneous inspiratory effort generates more negative pressure in the dorsal lung than in the ventral lung. The airflow caused by this pressure difference is called pendelluft, which is a possible mechanisms of patient self-inflicted lung injury. This study aimed to use computer simulation to understand how the endotracheal tube and insufficient ventilatory support contribute to pendelluft. We established two models. In the invasive model, an endotracheal tube was connected to the tracheobronchial tree with 34 outlets grouped into six locations: the right and left upper, lower, and middle lobes. In the non-invasive model, the upper airway, including the glottis, was connected to the tracheobronchial tree. To recreate the inspiratory effort of acute respiratory distress syndrome patients, the lower lobe pressure was set at -13 cmH2O, while the upper and middle lobe pressure was set at -6.4 cmH2O. The inlet pressure was set from 10 to 30 cmH2O to recreate ventilatory support. Using the finite volume method, the total flow rates through each model and toward each lobe were calculated. The invasive model had half the total flow rate of the non-invasive model (1.92 L/s versus 3.73 L/s under 10 cmH2O, respectively). More pendelluft (gas flow into the model from the outlets) was observed in the invasive model than in the non-invasive model. The inlet pressure increase from 10 to 30 cmH2O decreased pendelluft by 11% and 29% in the invasive and non-invasive models, respectively. In the invasive model, a faster jet flowed from the tip of the endotracheal tube toward the lower lobes, consequently entraining gas from the upper and middle lobes. Increasing ventilatory support intensifies the jet from the endotracheal tube, causing a venturi effect at the bifurcation in the tracheobronchial tree. Clinically acceptable ventilatory support cannot completely prevent pendelluft.

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Positive end-expiratory pressure and prone position alter the capacity of force generation from diaphragm in acute respiratory distress syndrome: an animal experiment

Cited by 4 publications

References 25 publications

The Effects of Positive End Expiratory Pressure and Lung Volume on Diaphragm Thickness and Thickening

The Effects of Positive End Expiratory Pressure and Lung Volume on Diaphragm Thickness and Thickening

Positive end-expiratory pressure limits inspiratory effort through modulation of the effort-to-drive ratio: an experimental crossover study

Endotracheal tube, by the venturi effect, reduces the efficacy of increasing inlet pressure in improving pendelluft

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