Aims: 

Severe sepsis is a leading cause of mortality in the intensive care unit. Former studies have not elucidated clearly the contribution of microparticles in the course of this critical illness. We aimed to follow the quantitative and proportional changes of platelet, leukocyte and endothel derived microparticles in the blood of severe septic patients. First, we assessed the difference of microparticle numbers and types in the course of severe sepsis. Second, we tested the outcome predictive value of microparticles in severe sepsis.

Methods: 

Our prospective study included 33 severe septic patients (2 or more organ dysfunctions and procalcitonine level above 5 ng/ml) studied for 5 days. Arterial blood samples were obtained on admission and on the 3^rd and 5^th study days for flow cytometry measurement. Besides the total number of Annexin V positive particles various markers were assessed including: CD13, CD14, CD41, CD42a, CD61, PAC1 and CD62E. An age and gender adopted healthy volunteer group of 20 individuals was invited as controls.

Results: 

Increased total plasma MP counts were measured in septic patients compared to controls (p < 0.01). The CD61 and CD41 platelet markers were elevated compared to controls throughout our study (p < 0.05). The endothelial CD62E marker showed no significant difference in septic patients. The CD13 positive particle numbers were elevated in all measurements (p < 0.05). Sepsis severity according to SOFA and MODS scores showed no correlation with the actual number and marker distribution of microparticles.

Conclusion: 

In accordance with previous data, the number of platelet and macrophage derived particles was elevated in the blood of severe septic patients. Although their physiological and pathophysiological role is still unclear, in our view the negative phospholipid surface and tissue factor from microparticles may crucially contribute to the development of severe sepsis related microcirculatory disturbances.

Support: 

OTKA 78480