Physiological Consequences of Breathing Effort According to the Mode of Ventilation during Acute Hypoxemic Respiratory Failure
Irene Telías, Matías Madorno, Tài Pham, Rémi Coudroy, Ricard Mellado Artigas, Elias Baedorf-Kassis, Chang-Wen Chen, Savino Spadaro, Davide Chiumello, Jeremy R. Beitler, Εumorfia Kondili, Norberto Tiribelli, Sebastián Fredes, Tobias Becher, Martin Dres, Kuan Liu, Nicolas Terzi, Claude Guérin, Tommaso Mauri, Oriol Roca, Jordi Mancebo, Núria Rodríguez, Jean-Michel Arnal, Ewan C. Goligher, Jean-Luc Diehl, Sébastien Jochmans, François Beloncle, Nuttapol Rittayamai, Francesco Mojoli, Leo Heunks, Heder de Vries, Jian-Xin Zhou, Christophe Guervilly, Laurent Brochard, the BEARDS and PLUG Investigators, Laurent Brochard, Irene Telias, Felipe Damiani, Cesar Santis, Tài Pham, Thomas Piraino, Michael Sklar, Tommaso Mauri, Elena Spinelli, Giacomo Grasselli, Nadia Corcione, Francesca Dalla Corte, Savino Spadaro, Carlo Alberto Volta, Francesco Mojoli, Dimitris Georgopoulos, Eumorfia Kondili, Stella Soundoulounaki, Tobias Becher, Norbert Weiler, Dirk Schaedler, Oriol Roca, Manel Santafe, Jordi Mancebo, Nuria Rodriguez, Leo Heunks, Heder de Vries, Chang Wen Chen, Jian-Xin Zhou, Guang-Qiang Chen, Nuttapol Rittayamai, Norberto Tiribelli, Sebastian Fredes, Ricard Artigas Mellado, Carlos Ferrando Ortolá, François Beloncle, Alain Mercat, Jean-Michel Arnal, Jean-Luc Diehl, Romy Younan, Alexandre Demoule, Martin Dres, Quentin Fossé, Sébastien Jochmans, Jonathan Chelly, Nicolas Terzi, Claude Guérin, Elias Baedorf-Kassis, Jeremy Beitler, Davide Chiumello, Erica Ferrari Luca Bolgiaghi, Arnaud W Thille, Rémi Coudroy, Laurent Papazian, Christophe Guervilly, Ewan C Goligher, Niall D Ferguson
Abstract
RATIONALE: Excessive stress (distending pressure), strain (volume deformation), and drop in inspiratory alveolar pressure are proposed mechanisms for patient self-inflicted lung injury. OBJECTIVES: To dissect the influence of inspiratory effort, respiratory mechanics, and ventilation mode on lung stress, strain, and drop in inspiratory alveolar pressure and to explore their impact on oxygenation and lung compliance. METHODS: An international cohort study was conducted analyzing respiratory recordings (esophageal pressure) from patients with acute hypoxemic respiratory failure. Association between muscular pressure (Pmus), surrogates of stress (driving transalveolar pressure), strain (Vt), and inspiratory alveolar pressure relative to positive end-expiratory pressure (PEEP) were explored using mixed models, including interactions for ventilation mode, respiratory system elastance, and synchrony. Association between these and changes in oxygenation and lung compliance were explored. MEASUREMENTS AND MAIN RESULTS: Sixty patients from 15 centers represented 528 recordings (339,796 breaths). For each 1 cm H2O increase in Pmus, there were increases in driving transalveolar pressure (median [95% confidence interval (CI)], 0.28 [0.27 to 0.29] cm H2O) and Vt (median [95% CI], 0.16 [0.16 to 0.17] ml/kg of predicted body weight) and a decrease in alveolar pressure (median [95% CI], 0.25 [0.24 to 0.6] cm H2O; P < 0.001). Volume-control ventilation showed lesser increases in stress and strain surrogates than pressure-targeted modes but more drop in alveolar pressure (P < 0.001; Pmus-by-mode interaction). Breath stacking was infrequent and was associated with higher stress. Lower inspiratory alveolar pressure relative to PEEP was associated with subsequent worsening oxygenation (P = 0.04) and higher stress with worsening lung compliance (P = 0.023). CONCLUSIONS: Strong efforts are associated with high surrogates for lung stress, strain, and lower inspiratory alveolar pressure relative to PEEP, differently according to the mode of ventilation, and are associated with subsequent worsening oxygenation and lung compliance.