Serial changes in leukcocyte deformability and whole blood rheology in patients with sepsis or trauma

Background: The objective of this study was to investigate serial changes in leukocyte deformability and rheologic properties of whole blood in patients with sepsis or trauma. Methods: Seventeen sepsis patients and 22 trauma patients were enrolled. Leukocyte deformability and rheologic properties of whole blood were determined with the use of a microchannel array etched on a single-crystal silicon tip, simulating the microvasculature. The number of obstructed microchannels (NOM) was used as a measure of leukocyte deformability. Transit time (TT), i.e., the time taken for 100 mu L of whole blood to pass through the microchannel array was also used as rheologic measure. Oxidative activity and F-actin content of neutrophils was measured in patients with sepsis. Results: NOM and TT significantly increased in patients when sepsis was diagnosed. In survivors, NOM and TT decreased at the time of recovery from sepsis, but in non-survivors values remained high. Oxidative activity and F-actin content of neutrophils increased significantly as leukocyte deformability decreased. In patients with severe trauma, NOM and TT increased after injury and decreased by the time of recovery from the critical stage. Conclusion: We conclude that leukocyte deformability decreases in patients with sepsis or severe trauma and that this change negatively affects rheologic properties of whole blood.