Effects of resuscitation fluids on nonadaptive immune responses

BACKGROUND: Colloidal plasma-expander fluids are commonly used as an alternative to blood components in the resuscitation of patients suffering from hemorrhagic shock and trauma. Of these, hydroxyethyl starch is also used as a cryopreservative, and these dual properties have been utilized in the development of a blood storage system that allows the direct transfusion of red cells. The prolonged intravascular persistence of hydroxyethyl starch suggests that phagocytic clearance may be impaired and that the presence of hydroxyethyl starch could exacerbate transfusion-induced immunomodulation. STUDY DESIGN AND METHODS: The effects of colloidal resuscitation fluids on the activation response and phagocytic function of polymorphonuclear cells (PMNs) and monocytes in normal peripheral blood were examined. To mimic the hemolysis associated with cryopreservation, the effects of 1- and 5-percent red cell lysate were studied. Flow cytometric assays were used in all cases. RESULTS: The percentage of phagocytic monocytes and PMNs was not altered; nor were the rates of phagocytosis impaired after incubation with resuscitation fluids. Upregulation of cell surface integrin during activation was similarly unmodified by the fluids. CONCLUSION: Hydroxyethyl starch and other resuscitation fluids do not affect some important antimicrobial functions of the nonadaptive arm of the immune response. This suggests that posttrauma or transfusion-induced immunomodulation is not exacerbated by inhibition at this level.