A 64-year-old woman is admitted to the hospital with right lobar pneumonia and sepsis syndrome. She becomes progressively shorter of breath and hypoxemic requiring intubation and mechanical ventilation. Her repeat CXR in the intensive care unit now shows diffuse pulmonary infiltrates and a diagnosis of acute respiratory distress syndrome (ARDS) is made. Which of the following mechanisms is the most likely cause for the early "exudative" phase of ARDS?