Microcirculatory dysfunction and tissue oxygenation in critical illness.

Severe sepsis is defined by organ failure, often of the kidneys, heart, and brain. It has been proposed that inadequate delivery of oxygen, or insufficient extraction of oxygen in tissue, may explain organ failure. Despite adequate maintenance of systemic oxygen delivery in septic patients, their morbidity and mortality remain high. The assumption that tissue oxygenation can be preserved by maintaining its blood supply follows from physiological models that only apply to tissue with uniformly perfused capillaries. In sepsis, the microcirculation is profoundly disturbed, and the blood supply of individual organs may therefore no longer reflect their access to oxygen. We review how capillary flow patterns affect oxygen extraction efficacy in tissue, and how the regulation of tissue blood flow must be adjusted to meet the metabolic needs of the tissue as capillary flows become disturbed as observed in critical illness. Using the brain, heart, and kidney as examples, we discuss whether disturbed capillary flow patterns might explain the apparent mismatch between organ blood flow and organ function in sepsis. Finally, we discuss diagnostic means of detecting capillary flow disturbance in animal models and in critically ill patients, and address therapeutic strategies that might improve tissue oxygenation by modifying capillary flow patterns.

[Leukemia of plasma cells]. / Leucemia de celulas plasmáticas

A case of plasma cell leukemia is reported, together with a review of the literature, including a summary of the signs, symptoms and laboratory findings usually present. The relationship of this leukemic state to ordinary multiple myeloma is discussed.

[IgA multiple myeloma with osseous lesions (laryngeal plasmocytom)]. / Mieloma Múltiple IgA, con lesiones extraoseas (plasmocitoma laríngeo)

One case of myeloma IgA is presented. It was associated with laringeal plasmocytoma and other lesions that afected superior airways The association hypergammaglobuinemia IgA and extraosseus lesions are under discussion. The extraosseus plasmcytomas can be seen in the presence of osteolytic lesions of multiple myeloma, or can appear independently. The prognosis can be better in the presence of disseminated skeletical lesions with few manifestations of tisular infiltrate, as in the present case. Despite the fact that extramedular plasmocytomas are rare, they must be considered in the differential diagnosis of laringeal tumors.