Microembolism in experimental septic shock. Distribution of platelets and fibrinogen after intravenous injection of disintegrated Pseudomonas bacteria to dogs.

Platelets were labelled with 51Cr, fibrinogen with 125I and erythrocytes with 59Fe. Disintegrated Pseudomonas bacteria were injected intravenously and radioactive measurements were made on whole blood; tissue biopsies and clottable fibrinogen. After the infection there was an immediate but transient increase of 51Cr activity in the lung concomitant with a decrease in platelet count and 51Cr activity of blood. In the liver there was a less pronounced increase of 51Cr activity. The fibrinogen concentration decreased slightly, paralleled by the 125I activity of whole blood and of clottable fibrinogen, whereas the 125I activity in the lung and liver remained fairly constant. There was no changes of 51Cr activity or 125I activity in biopsies from muscle, pancreas, small intestine, kidney or spleen. During the experiment (3h) there were no signs of significant disseminated intravascular coagulation other than platelet aggregation. A consumption of fibrinogen related to the formation of fibrin plugs could not be detected. After injection of disintegrated Pseudomonas bacteria reversible platelet aggregates were formed and temporarily trapped in the pulmonary microcirculation. This microembolism might induce tissue damage and could be of importance for the development of septic pulmonary complication.