Immunological effects of CWHD in critically ill patients

Acute renal failure as part of the multi-organ dysfunction syndrome (MODS) is a severe complication in critically ill patients. Hemodynamic instability is common in these patients and exacerbated by hemodialysis (HD). Therefore, continuous veno-venous hemodiafiltration (CVVHD) is used as an alternative to conventional HD. The aim of the study was to test the hypothesis that initiation of CVVHD elicits an acute activation of the immune system followed by immunosuppression.

Patient and methods

Fifteen consecutive, septic patients with acute renal failure were treated with CVVHD in the ICU. The study was approved by the Regional Ethical Committee on Human Research and informed consent was obtained from the patients or a close relative. The cellular response was measured as the distribution of the CD3⁺, CD4⁺ and CD8⁺ lymphocytes (flow cytometry), and the leukocyte adhesion molecules CD1la, CD11b, CD16, CD18, CD44 and CD42 (flow cytometry). The humoral response was estimated as plasma cortisol (RIA), the proinflammatory cytokines TNFα and IL-8 and the anti-inflammatory cytokine IL-10 (ELISA), and the complement split products C3d and C4d (RIE).

Results

Ten men and five women were included. Eleven patients developed MODS after abdominal surgery, 4 patients sufferedfrom medical diseases. Mean age was 59 years (range 25–75 years). Mean APACHE II score before CVVHD was 19 (range 8–27). Nine patients (60%) died in septic shock. Mean duration of CVVHD treatment was 9 days (1–21 days). TNFα and IL-8 were detectable in all patients, while IL-10 was detectable only in a few patients. Low cytokine concentrations were measured in the ultra-filtrate. Big intra- and interindividual variations were demonstrated for all the immunological parameters. In summary, no significant changes were demonstrated in any of the immunological variables.

Conclusions

The hypothesis that CVVHD induces an acute activation of the immune system followed by immunosupression was not confirmed in the present study. The heterogenic patient material with different underlying diseases and various duration of illness before start of CVVHD may contribute to the large variation in the measured immunological markers