Procalcitonin and proinflammatory cytokine clearance during continuous venovenous haemofiltration in septic patients

Procalcitonin (PCT), interleukin-6 (IL-6), tumour necrosis factor alpha (TNFalpha), and interleukin-1beta (IL-1beta) are important clinical prognostic markers in ICU septic patients. The goal of the study was to determine whether continuous venovenous haemofiltration (CVVH), using an AN69 haemofilter, leads to elimination of PCT, TNFalpha IL-6 and IL-1beta in 1.3 septic patients with multi-organ failure. At the start of haemofiltration (0), 6 and 12 hours the mean afferent plasma concentration +/-SD of PCT (10.1 +/- 9.1, 7 +/- 6, 5.9 +/- 5.7 ng/ml), IL-6 (804.6 +/- 847.6, 611.7 +/- 528.4, 575.2 +/- 539.2 pg/ml), and that of TNFalpha (4.5 +/- 2.6, 4 +/- 3.1, 3.8 +/- 2.9 pg/ml) significantly declined during CVVH. The efferent plasma concentrations were significantly lower than the corresponding afferent concentrations. PCT, IL-6 and TNFalpha were detectable in the ultrafiltrate of all patients. IL-1beta was only detectable in the plasma of eight patients and the ultrafiltrate of five patients. The plasma clearance of PCT, IL-6 and TNFalpha significantly decreased after 12 hours as a result of a decline in the adsorptive elimination of the mediators due to progressive membrane saturation. We demonstrated that if PCT, IL-6 and TNFalpha are used as clinical prognostic markers in septic patients who are treated with CVVH using an AN69 membrane, one should be aware that their plasma level could be modified by the therapy. In addition CVVH could represent an appropriate tool to remove a broad spectrum of proinflammatory mediators, if such removal is required in septic patients.