Continuous arteriovenous hemofiltration attenuates polymorphonuclear leukocyte phagocytosis in porcine intra-abdominal sepsis

Background Activation of circulating polymorphonuclear leukocytes (PMN) is a characteristic of systemic inflammation and may contribute to organ malfunction. Continuous arteriovenous hemofiltration (CAVH) has been reported to improve organ malfunction during severe systemic inflammation. This study postulates that the CAVH effects may be linked to alterations in PMN activation. Methods Sixteen pigs that underwent cecal ligation and rupture were randomized to receive CAVH or no CAVH for 24 hours. The PMN phagocytosis of Candida was measured prior to the insult and at 24, 48, and 72 hours. Temperature, total leukocyte count (WBC), hemodynamic, blood gas, microbiologic, and ionized calcium data were also collected. Results All animals developed increased temperature, heart rate, and WBC, and positive blood and peritoneal cultures. Hemodynamic, pulmonary, and ionized calcium changes were not different between the CAVH and no CAVH groups. Phagocytosis of PMN increased in the no CAVH group at 24 hours, but not in the CAVH group. After discontinuing CAVH, phagocytosis increased to the no CAVH rate at 48 and 72 hours. Conclusions Continuous arteriovenous hemofiltration attenuates the upregulation of PMN phagocytosis of Candida; this effect disappears after CAVH is discontinued. Hemofiltration does not affect many other manifestations of sepsis, which implies that these manifestations may not be related to PMN phagocytosis capacity