The immunological effects of continuous veno-venous haemodiafiltration in critically ill patients

Fifteen patients were included. Mean Acute Physiology and Chronic Health Evaluation-2 score before CVVHD was 19 (range 8–27). Mean duration of CVVHD treatment was 9 days (1–21 days). Tumour necrosis factor-α and interleukin-8 were detectable in plasma in all patients, whereas interleukin-10 was detectable only in a few patients. Proinflammatory and anti-inflammatory cytokines were detected in the ultrafiltrate. Large intraindividual and interindividual variations were demonstrated for all of the immunological parameters studied.The hypothesis that CVVHD induces the release of proinflammatory cytokines followed by a decrease in granulocyte activation was not confirmed in the present study. The heterogeneous group of patients studied, with different underlying diseases and various durations of illness before the start of CVVHD, might have contributed to the difficulty in demonstrating the proposed immunological effect of CVVHD.Acute renal failure as part of the multiorgan dysfunction syndrome (MODS) is a severe complication in critically ill patients. Haemodynamic instability is common in these patients and is exacerbated by haemodialysis. Continuous veno-venous haemodiafiltration (CVVHD) is therefore used as an alternative to conventional haemodialysis.It is well documented that different types of extracorporeal circulation, such as haemodialysis using cuprophane membranes and cardiopulmonary bypass (CPB), are associated with complement activation [1,2]; granulocytopenia followed by granulocytosis [3], granulocyte activation and degranulation [3,4]; increased production of proinflammatory and anti-inflammatory cytokines; and increased acute-phase protein synthesis [5,6]. In fact, CPB elicits a well defined, temporary, systemic inflammatory response, which may contribute to organ dysfunction postoperatively. CPB using a membrane oxygenator is, however, used for 1–2 h during cardiocirculatory arrest, and thus differs from CVVHD and haemodialysis. The above mentioned ef