Removal of inflammatory mediators by continuous renal replacement therapy in severe sepsis

Introduction

The aim of this study was to evaluate the efficacy of continuous renal replacement therapy (CRRT) in systemic inflammatory mediator removal in a group of patients with severe sepsis/septic shock and related renal failure.

Methods

We conducted a prospective study, approved by the ethics committee, enrolling 11 patients with severe sepsis/septic shock under CRRT. We measured the cytokines using the immunoassay method. The cytokine measurement was done every morning until the end of renal support. We analyzed the following data: age, severity scores (Simplified Acute Physiology Score (SAPS) II, Sequential Organ Failure Assessment (SOFA)), cytokines (TNF, IL-1β, IL-6 and IL-10) levels on pre-filter, post-filter and ultrafiltrate samples. We correlated these data with filter duration, considering 24 hours as the maximum theoretical limit for effective cytokine removal.

Results

From the 11 patients enrolled, we collected 420 valid samples to measure the cytokine levels. The mean age and SAPS II were respectively 66 ± 10.7 years and 46 ± 27.1. The mean total SOFA score at admission and at day 3 were 11.2 ± 4 and 12.7 ± 4 respectively, with ΔSOFA = +1.3 points (P > 0.05). The mean ICU hospitalization time was 25.9 ± 33.5 days. We have done 876 hours of dialytic therapy; 33 AN69 membranes were used, during a mean time of 26.5 ± 25.6 hours. The mean total levels found for cytokines are presented in Figure 1 and the levels depending on the filter duration are in Figure 2. The ICU mortality was 54.6%.

Figure 1

(abstract P269)Total cytokine levels.

Figure 2

(abstract P269)Removal of inflammatory mediators according to filter duration.

Conclusion

The present study does not allow us to define a specific pattern for the removal of inflammatory mediators related to CRRT. We observed a trend for cytokine reduction dependent on filter duration with the higher efficacy removal until 24 hours. The cytokine level found in the effluent does not reflect the absolute reduction found in post-filter, and this effect could be dependent on adsorption, according to other studies [1, 2].