Serum IL-6 and IL-1-ra with sequential organ failure assessment scores in septic patients receiving high-volume haemofiltration and continuous venovenous haemofiltration.

AIM: Sepsis is characterized by an uncontrolled release of pro-inflammatory and anti-inflammatory mediators leading to immunoparalysis, cellular and humoral dysfunction, multiorgan dysfunction and death. This study evaluated the efficacy of high-volume haemofiltration (HVHF) compared with continuous venovenous haemofiltration (CVVH) in removing these inflammatory mediators. Clinical responses were assessed with the sequential organ failure assessment (SOFA) score.

METHODS: Septic patients with an end-organ dysfunction or septic shock were randomized to receive 6 h of CVVH (ultrafiltration dose of 2 L/h equivalent to about 35 mL/kg per hour or HVHF (ultrafiltration dose of 100 mL/kg per hour or 6 L/h, whichever was higher). The sequential organ failures were scored for the 24 hours preceding recruitment; at day 1, day 7, at discharge from the intensive care unit and at hospital discharge.

RESULTS: Thirty-three patients were enrolled. Fifteen received HVHF and 18 received CVVH. The serum IL-6 levels (pg/mL) at baseline were similarly elevated in both groups (P = 0.745). The HVHF group showed a significant reduction after 6 h of treatment with a median interquartile range (IQR) of 20.62 (49.21) pg/mL (P = 0.025) with no similar result in the CVVH group. Non-survivors showed a higher baseline serum IL-6 compared with the survivors (median (IQR) 172.31 (261.34) vs 58.9 (104.21), P = 0.044). In the HVHF group there was a positive association between the IL-6 levels at 6 h with the SOFA scores at day 1 (r = 0.392, P = 0.001) but not at day 7. After 6 h of treatment in the HVHF group there was a direct correlation between the IL-6 levels and number of hospital days (r = 0.90, P = 0.040). The maximum SOFA scores were persistently recorded before treatment. The SOFA scores reduced in both groups from baseline to day 7 (HVHF P = 0.048; CVVH P = 0.006). The SOFA scores at day 1 is significantly higher in the non-survivors compared with the survivors (P = 0.038).

CONCLUSIONS: High-volume haemofiltration at 6 L/h may seem to successfully remove some inflammatory cytokines in septic patients. The improvement in the SOFA scores at day 7 promises benefit of continuous renal replacement therapy in septic patients, but after 20 days this effect may be lost. In addition, the baseline serum IL-6 and IL-1-ra were independent predictors of a poor outcome as reflected by the higher SOFA scores at day 1.