The effect of CVVHD and endotoxin on the oxidative burst, adhesion molecules and distribution in tissues of granulocytes

Objective: Extracorporeal circulation, such as cardiopulmonary bypass and h aemodialysis, has been associated with an activation of the immune system, especially the granulocytes. Continuous veno-venous haemodiafiltration (CVV HD) is used in critically ill septic patients. During CVVHD cytokines are e xcreted in the ultrafiltrate. But when the membranes used in CVVHD are cult ured with granulocytes, the granulocytes are slightly activated. This effec t is potentiated by endotoxin. We therefore, in vivo, compared the effect o n granulocyte activation of CVVHD with an endotoxin group and a control gro up. Methods: Thirty-one pigs were anaesthetized and mechanically ventilated. In ten pigs CVVHD was performed. Eleven pigs received an infusion of Escheric hia coil endotoxin 30 mu/kg(-1) and ten pigs served as a control group. The adhesion molecules CD18 and CD62L were measured using monoclonal antibodie s. The oxidative burst activity was assayed as superoxide dismutase-inhibit ory reduction of cytochrome c. The number of granulocytes in peripheral blo od and in the lungs and liver were counted. Results: The infusion of endotoxin was followed by granulocytopenia, reduce d oxidative burst activity, increased expression of CD18 and decreased expr ession of CD62L on granulocytes. Accumulation of granulocytes in liver and lung tissue was also noted in this group. CVVHD was only associated with a non-significant decrease in CD62L expression on granulocytes. It did not af fect any of the other measured immunological parameters. Conclusion: In con trast to endotoxin-induced sepsis, the granulocytes were not activated duri ng CVVHD.