Acute respiratory distress syndrome remains a serious condition, with a mortality rate of
between 30 and 50%. The use of mechanical ventilation with small tidal volumes, and by
limiting the plateau pressure in the respiratory tract below 30 cm H2O has been shown to
reduce mortality by approximately 10%, probably by reducing pulmonary hyperinflation and
pulmonary lesions induced by mechanical ventilation. It is therefore now established that the
respirator settings influence patient prognosis. However, around 30% of patients with ARDS
ventilated with these settings supposedly protective continue to present signs of pulmonary
hyperinflation on tomodensitometry, suggesting an additional reduction in the tidal volume
could be required in certain patients. Electrical impedance tomography (EIT) is a new imaging
technique that gathers functional pulmonary information at bedside.
This technique also allows a regional analysis, allowing the complexity of the spatial
distribution of ARDS pulmonary lesions to be understood. The hypothesis is that EIT is a
reliable method to detect at-risk situations of lesions induced by mechanical ventilation
among patients with ARDS.