Elena Spinelli1, Michael Kircher2, Birgit Stender3, Irene Ottaviani1, Maria C Basile1, Ines Marongiu4, Giulia Colussi1, Giacomo Grasselli1,4, Antonio Pesenti1,4, Tommaso Mauri5,6. 1. Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy. 2. Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany. 3. Drägerwerk AG & Co. KGaA, Lübeck, Germany. 4. Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy. 5. Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy. tommaso.mauri@unimi.it. 6. Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy. tommaso.mauri@unimi.it.
Abstract
BACKGROUND: In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions might reflect ARDS severity and affect the risk of ventilation-induced lung injury. Despite pathophysiological relevance, unmatched ventilation and perfusion are not routinely assessed at the bedside. The aims of this study were to quantify unmatched ventilation and perfusion at the bedside by electrical impedance tomography (EIT) investigating their association with mortality in patients with ARDS and to explore the effects of positive end-expiratory pressure (PEEP) on unmatched ventilation and perfusion in subgroups of patients with different ARDS severity based on PaO2/FiO2 and compliance. METHODS: Prospective observational study in 50 patients with mild (36%), moderate (46%), and severe (18%) ARDS under clinical ventilation settings. EIT was applied to measure the regional distribution of ventilation and perfusion using central venous bolus of saline 5% during end-inspiratory pause. We defined unmatched units as the percentage of only ventilated units plus the percentage of only perfused units. RESULTS: Percentage of unmatched units was significantly higher in non-survivors compared to survivors (32[27-47]% vs. 21[17-27]%, p < 0.001). Percentage of unmatched units was an independent predictor of mortality (OR 1.22, 95% CI 1.07-1.39, p = 0.004) with an area under the ROC curve of 0.88 (95% CI 0.79-0.97, p < 0.001). The percentage of ventilation to the ventral region of the lung was higher than the percentage of ventilation to the dorsal region (32 [27-38]% vs. 18 [13-21]%, p < 0.001), while the opposite was true for perfusion (28 [22-38]% vs. 36 [32-44]%, p < 0.001). Higher percentage of only perfused units was correlated with lower dorsal ventilation (r = - 0.486, p < 0.001) and with lower PaO2/FiO2 ratio (r = - 0.293, p = 0.039). CONCLUSIONS: EIT allows bedside assessment of unmatched ventilation and perfusion in mechanically ventilated patients with ARDS. Measurement of unmatched units could identify patients at higher risk of death and could guide personalized treatment.
BACKGROUND: In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions might reflect ARDS severity and affect the risk of ventilation-induced lung injury. Despite pathophysiological relevance, unmatched ventilation and perfusion are not routinely assessed at the bedside. The aims of this study were to quantify unmatched ventilation and perfusion at the bedside by electrical impedance tomography (EIT) investigating their association with mortality in patients with ARDS and to explore the effects of positive end-expiratory pressure (PEEP) on unmatched ventilation and perfusion in subgroups of patients with different ARDS severity based on PaO2/FiO2 and compliance. METHODS: Prospective observational study in 50 patients with mild (36%), moderate (46%), and severe (18%) ARDS under clinical ventilation settings. EIT was applied to measure the regional distribution of ventilation and perfusion using central venous bolus of saline 5% during end-inspiratory pause. We defined unmatched units as the percentage of only ventilated units plus the percentage of only perfused units. RESULTS: Percentage of unmatched units was significantly higher in non-survivors compared to survivors (32[27-47]% vs. 21[17-27]%, p < 0.001). Percentage of unmatched units was an independent predictor of mortality (OR 1.22, 95% CI 1.07-1.39, p = 0.004) with an area under the ROC curve of 0.88 (95% CI 0.79-0.97, p < 0.001). The percentage of ventilation to the ventral region of the lung was higher than the percentage of ventilation to the dorsal region (32 [27-38]% vs. 18 [13-21]%, p < 0.001), while the opposite was true for perfusion (28 [22-38]% vs. 36 [32-44]%, p < 0.001). Higher percentage of only perfused units was correlated with lower dorsal ventilation (r = - 0.486, p < 0.001) and with lower PaO2/FiO2 ratio (r = - 0.293, p = 0.039). CONCLUSIONS: EIT allows bedside assessment of unmatched ventilation and perfusion in mechanically ventilated patients with ARDS. Measurement of unmatched units could identify patients at higher risk of death and could guide personalized treatment.
Authors: S Crotti; D Mascheroni; P Caironi; P Pelosi; G Ronzoni; M Mondino; J J Marini; L Gattinoni Journal: Am J Respir Crit Care Med Date: 2001-07-01 Impact factor: 21.405
Authors: Serge Brimioulle; Valérie Julien; René Gust; James K Kozlowski; Robert Naeije; Daniel P Schuster Journal: Crit Care Med Date: 2002-04 Impact factor: 7.598
Authors: Elena Spinelli; Antonio Pesenti; Gianluca Lopez; Anna Damia; Francesco Damarco; Erica Garbelli; Gaia Dal Santo; Alessio Caccioppola; Giorgio Giudici; Virginia Figgiaconi; Osvaldo Biancolilli; Michele Battistin; Caterina Lonati; Valentina Vaira; Lorenzo Rosso; Stefano Ferrero; Stefano Gatti; Tommaso Mauri Journal: Front Med (Lausanne) Date: 2022-05-20