Changes in hemorheology in patients with sepsis or septic shock.

We studied hemorheological variables in ten consecutive patients with sepsis or septic shock. One patient with sepsis, eight with septic shock, and one with the toxic shock syndrome were included. The patients were studied during the first 3 days and the eighth day of their illness. All patients except one survived 1 week. Final outcome showed a 50% mortality. A decrease in low shear blood viscosity of red blood cells (RBC) suspended in plasma was observed. This indicates a decrease in RBC aggregation. These changes persisted during the first week. The decrease in RBC aggregation occurred despite a normal plasma viscosity. No correlations were found between the reduction in RBC aggregation and changes in blood chemistry, amounts of dopamine or plasma administered, or with the APACHE II score. A decrease in RBC deformability was observed, due to changes in the RBC membrane. After 1 week, these changes had disappeared. The change in RBC deformability during the study period was significantly related to changes in the amount of dopamine administered.