Role of Positive End-Expiratory Pressure and Regional Transpulmonary Pressure in Asymmetrical Lung Injury

Bastia, Luca; Engelberts, Doreen; Osada, Kohei; Katira, Bhushan; Damiani, L Felipe; Yoshida, Toyohiko; Chen, Lu; Ferguson, Niall D.; Amato, Marcelo B. P.; Post, Martin; Kavanagh, Brian P.; Brochard, Laurent

doi:10.1164/rccm.202005-1556oc

Cited by 18 publications

(17 citation statements)

References 33 publications

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“…At the end of each step, and after 5, 30 and 60 min of step 2 (ECC), we performed expiratory and inspiratory holds to obtain static measurements of airway ( P aw ) and esophageal pressure ( P es ). The distribution of tidal volume between ventral (non-dependent, regions of interest 1 + 2) and dorsal (dependent, regions of interest 3 + 4) lung areas was assessed through the analysis of EIT data (PulmoVista 500, Dräger, Lübeck, Germany) to obtain a regional V t as previously described [ 18 , 19 ]. In addition, end-expiratory lung impedance (EELI, a surrogate of end-expiratory lung volume [ 20 ]) was analyzed by EIT [ 21 ].…”

Section: Methodsmentioning

confidence: 99%

“…Pigs were intubated and mechanically ventilated in volume-controlled mode in supine position. An esophageal catheter (Nutrivent; Sidam, Mirandola, Italy) was inserted to record P es and positioned as previously described [ 17 , 18 ]. Pleural pressure ( P pl ) was directly recorded in the dorsal and ventral part of the pleural space in the right lung with two balloons (Cooper surgical, Trunbull, CT, USA).…”

Section: Methodsmentioning

confidence: 99%

“…Afterwards, we established lung injury by a two-hit model: surfactant depletion with saline lavage followed by injurious ventilation, as described previously [ 18 ].…”

Section: Methodsmentioning

confidence: 99%

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External chest-wall compression in prolonged COVID-19 ARDS with low-compliance: a physiological study

Bastia

Rezoagli

Guarnieri

et al. 2022

Ann. Intensive Care

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Background External chest-wall compression (ECC) is sometimes used in ARDS patients despite lack of evidence. It is currently unknown whether this practice has any clinical benefit in patients with COVID-19 ARDS (C-ARDS) characterized by a respiratory system compliance (Crs) < 35 mL/cmH2O. Objectives To test if an ECC with a 5 L-bag in low-compliance C-ARDS can lead to a reduction in driving pressure (DP) and improve gas exchange, and to understand the underlying mechanisms. Methods Eleven patients with low-compliance C-ARDS were enrolled and underwent 4 steps: baseline, ECC for 60 min, ECC discontinuation and PEEP reduction. Respiratory mechanics, gas exchange, hemodynamics and electrical impedance tomography were recorded. Four pigs with acute ARDS were studied with ECC to understand the effect of ECC on pleural pressure gradient using pleural pressure transducers in both non-dependent and dependent lung regions. Results Five minutes of ECC reduced DP from baseline 14.2 ± 1.3 to 12.3 ± 1.3 cmH2O (P < 0.001), explained by an improved lung compliance. Changes in DP by ECC were strongly correlated with changes in DP obtained with PEEP reduction (R2 = 0.82, P < 0.001). The initial benefit of ECC decreased over time (DP = 13.3 ± 1.5 cmH2O at 60 min, P = 0.03 vs. baseline). Gas exchange and hemodynamics were unaffected by ECC. In four pigs with lung injury, ECC led to a decrease in the pleural pressure gradient at end-inspiration [2.2 (1.1–3) vs. 3.0 (2.2–4.1) cmH2O, P = 0.035]. Conclusions In C-ARDS patients with Crs < 35 mL/cmH2O, ECC acutely reduces DP. ECC does not improve oxygenation but it can be used as a simple tool to detect hyperinflation as it improves Crs and reduces Ppl gradient. ECC benefits seem to partially fade over time. ECC produces similar changes compared to PEEP reduction.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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External chest-wall compression in prolonged COVID-19 ARDS with low-compliance: a physiological study

Bastia

Rezoagli

Guarnieri

et al. 2022

Ann. Intensive Care

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“…As shown previously PEEP titrated to the lowest E stat,RS might be associated with negative end-expiratory transpulmonary pressure [ 18 ]. Aiming for a positive end-expiratory transpulmonary pressure might, therefore, be a viable strategy to further reduce atelectatic lung volume especially in dependent lung regions to reduce cyclic opening and closing of the alveoli (atelectrauma), to homogenize V T distribution and to avoid overdistension [ 37 ]. The V T of the ultraprotective ventilation strategy causes additional dynamic strain compared to the static strain induced by PEEP in the inflamed inhomogeneous lung.…”

Section: Discussionmentioning

confidence: 99%

Ultraprotective versus apneic ventilation in acute respiratory distress syndrome patients with extracorporeal membrane oxygenation: a physiological study

et al. 2022

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Background Even an ultraprotective ventilation strategy in severe acute respiratory distress syndrome (ARDS) patients treated with extracorporeal membrane oxygenation (ECMO) might induce ventilator-induced lung injury and apneic ventilation with the sole application of positive end-expiratory pressure may, therefore, be an alternative ventilation strategy. We, therefore, compared the effects of ultraprotective ventilation with apneic ventilation on oxygenation, oxygen delivery, respiratory system mechanics, hemodynamics, strain, air distribution and recruitment of the lung parenchyma in ARDS patients with ECMO. Methods In a prospective, monocentric physiological study, 24 patients with severe ARDS managed with ECMO were ventilated using ultraprotective ventilation (tidal volume 3 ml/kg of predicted body weight) with a fraction of inspired oxygen (FiO2) of 21%, 50% and 90%. Patients were then treated with apneic ventilation with analogous FiO2. The primary endpoint was the effect of the ventilation strategy on oxygenation and oxygen delivery. The secondary endpoints were mechanical power, stress, regional air distribution, lung recruitment and the resulting strain, evaluated by chest computed tomography, associated with the application of PEEP (apneic ventilation) and/or low VT (ultraprotective ventilation). Results Protective ventilation, compared to apneic ventilation, improved oxygenation (arterial partial pressure of oxygen, p < 0.001 with FiO2 of 50% and 90%) and reduced cardiac output. Both ventilation strategies preserved oxygen delivery independent of the FiO2. Protective ventilation increased driving pressure, stress, strain, mechanical power, as well as induced additional recruitment in the non-dependent lung compared to apneic ventilation. Conclusions In patients with severe ARDS managed with ECMO, ultraprotective ventilation compared to apneic ventilation improved oxygenation, but increased stress, strain, and mechanical power. Apneic ventilation might be considered as one of the options in the initial phase of ECMO treatment in severe ARDS patients to facilitate lung rest and prevent ventilator-induced lung injury. Trial registration: German Clinical Trials Register (DRKS00013967). Registered 02/09/2018. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00013967.

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“…Static airway pressures are the same in the whole lung, which means that the transpulmonary driving pressure is the same in the whole lung [33]. Consequently, gas delivered as a tidal volume or by PEEP inflation is distributed according to the regional elastic properties of the lung [34].…”

Section: Distribution Of δEelv and Tidal Volumementioning

confidence: 99%

Gas distribution and optimal PEEP with lowest transpulmonary driving pressure (without esophageal pressure) during a PEEP trial. A post hoc analysis in patients with acute respiratory failure.

Grivans

Stenqvist²

2022

Preprint

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Background: A protective ventilation strategy should be based on assessment of lung mechanics and transpulmonary pressure (PTP), as this is the pressure that directly “hits” the lung. Protective ventilation with tidal volumes of 6 ml/kg ideal body weight is generally accepted, but there is no consensus on selection of optimal PEEP. We have shown that the change in end-expiratory lung volume (ΔEELV) is determined by the size of the PEEP step and the elastic properties of the lung (only), ΔEELV/ΔPEEP. Consequently, lung elastance (EL) can be determined as ΔPEEP/ΔEELV.The aim was to determine the PEEP level with lowest (least injurious) transpulmonary driving pressure and to identify what signifies high or low PEEP response.Methods: In ten patients with acute respiratory failure, global and ventral-dorsal tidal volume and ΔEELV were determined by inspiratory tidal volume calibrated EIT during a PEEP step procedure from 0 to 16 cmH2O. As the lung pressure/volume (P/V) curve coincides with the line connecting the end-expiratory airway P/V points, a complete lung P/V curve can be obtained for the whole lung or by combination with EIT, for the ventral and dorsal lung separately. Results: Global lung P/V curves showed marked individual variation with overall lung elastance of 7.0 – 23.2 cmH2O/L. Optimal PEEP level was 12.9 cmH2O (10-16) with ΔPTP of 4.1 cmH2O (2.8-7.6). The ratio of ΔPTP to airway driving pressure (ΔPAW), ΔPTP/ΔPAW, varied between patients and changed with changes of PEEP, making ΔPAW a less suitable surrogate for ΔPTP in individual patients. The two patients with highest EL were non-responders to PEEP with increasing global, ventral and dorsal lung elastance at high PEEP levels, indicating non-dependent over-distension. In patients with lower lung elastance, there was positive response to PEEP with successively lower lung elastance when increasing PEEP, especially in dorsal (dependent) lung. Conclusion: Only a two PEEP step up-down procedure is required for obtaining a full best-fit lung P/V curve, from which the PEEP level with the lowest transpulmonary driving pressure could be calculated. High PEEP response is signified by low lung elastance, which increases at high PEEP levels both globally and in dorsal lung.

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Role of Positive End-Expiratory Pressure and Regional Transpulmonary Pressure in Asymmetrical Lung Injury

Cited by 18 publications

References 33 publications

External chest-wall compression in prolonged COVID-19 ARDS with low-compliance: a physiological study

External chest-wall compression in prolonged COVID-19 ARDS with low-compliance: a physiological study

Ultraprotective versus apneic ventilation in acute respiratory distress syndrome patients with extracorporeal membrane oxygenation: a physiological study

Gas distribution and optimal PEEP with lowest transpulmonary driving pressure (without esophageal pressure) during a PEEP trial. A post hoc analysis in patients with acute respiratory failure.

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