Electrical Impedance Tomography-Informed Regional Functional Phenotypes in Sepsis-Associated Acute Respiratory Distress Syndrome

Abstract: Sepsis-associated acute respiratory distress syndrome (SA-ARDS) is a heterogeneous syndrome in which systemic inflammation, vascular dysfunction, altered fluid balance, chest-wall loading, and respiratory effort may produce regional abnormalities not captured by global respiratory variables. Electrical impedance tomography (EIT) provides continuous bedside assessment of regional ventilation and, increasingly, regional perfusion. This review summarizes EIT-derived measures relevant to SA-ARDS and examines how key sepsis-associated mechanisms may influence regional ventilation, perfusion, and mechanics. Six candidate functional patterns are proposed: collapse-shunt dominance, overdistension-dead-space dominance, perfusion-defect dominance, diffuse low aeration with limited recruitability, abdominal pressure-diaphragm interaction, and effort-related regional asynchrony. These patterns are neither mutually exclusive nor specific to SA-ARDS and may evolve over time. Keywords: sepsis-associated acute respiratory distress syndrome, electrical impedance tomography, regional ventilation, regional perfusion, ventilation-perfusion mismatch, functional phenotyping