Effect of immunoglobulin administration on blood rheology in patients with septic shock

The hemorrheological determinants plasma fibrinogen, plasma viscosity, red cell aggregation, and hematocrit were studied in 11 patients before and 4 and 24 hr after a 15 g immunoglobulin infusion to assess the effect of intravenous immunoglobulin administration on blood rheology in septic shock. Four hr after the immunoglobulin administration, plasma fibrinogen decreased significantly [472 (175-950) vs. 522 (182-1,050) mg/dl before administration; median (range); P < 0.01]; after 24 hr, plasma fibrinogen tended to increase again [501 (185-980); n.s.]. No changes were seen in plasma viscosity, red cell aggregation, hematocrit, and coagulation status 4 and 24 hr after immunoglobulin administration. In patients with septic shock, intravenous immunoglobulin administration leads to a decrease in plasma fibrinogen, whereas plasma viscosity and red cell aggregation remain unaffected. The explanation for the decrease in fibrinogen remains speculative.