Safety of Polymyxin-B–based Hemoperfusion in Kidney and Liver Transplant Recipients

Importance of Endotoxin Clearance in Endotoxemic Septic Shock: An Analysis From the Evaluating Use of PolymyxinB Hemoperfusion in a Randomized Controlled Trial of Adults Treated for Endotoxemic Septic Shock (EUPHRATES) Trial

To investigate the relationship between survival and treatment-related reduction in endotoxin activity for patients in the Evaluating Use of PolymyxinB Hemoperfusion in a Randomized controlled trial of Adults Treated for Endotoxemia and Septic shock trial with baseline endotoxin activity assay greater than or equal to 0.60 to less than 0.90 units.

Design

Post hoc analysis of a multicenter randomized controlled clinical trial.

Setting

Fifty-five tertiary hospitals in North America.

Patients

Patients with septic shock and endotoxin activity assay level greater than or equal to 0.60 to less than 0.90 and multiple organ dysfunction syndrome greater than 9.

Interventions

Two polymyxin B hemoperfusion treatments or Sham.

Measurements and Main Results

One-hundred ninety-four patients were included (88 polymyxin B and 106 Sham). We evaluated the impact of changes in endotoxin activity assay based on comparison to the median reduction from baseline to day 3 and a second method where a target post-treatment endotoxin activity assay level (day 3) was established. The population median reduction in endotoxin activity assay level was 10.4%. In patients with a greater than median reduction, there was trend toward lower mortality with polymyxin B (17.1% vs 33.3%; p = 0.07) and a significant increase in mechanical ventilation-free days (20 vs 13.5; p = 0.04). The pressure adjusted heart rate showed a significant improvement in the polymyxin B group (p = 0.02). For patients who achieved an endotoxin activity assay of less than 0.65 at day 3, the polymyxin B treated group had a trend toward a mortality reduction compared to Sham (16% vs 33%;p = 0.06) and a significant increase in ventilation-free day (20 vs 16; p = 0.05). Kaplan-Meier analysis showed a 17% reduction in mortality with polymyxin B (p = 0.04).

Conclusions

These findings suggest that reducing endotoxin activity assay levels with polymyxin B as measured by comparison to a median reduction or when a treatment target is established, may result in improvements in mortality and organ function outcomes. This article is the first to report endotoxin activity assay measurements in response to polymyxin B use versus Sham in patients with septic shock and elevated endotoxin activity assay. These findings are considered to be hypothesis generating and will need to be prospectively validated.

Chasing a ghost?--Issues with the determination of circulating levels of endotoxin in human blood

Reliable quantification of bacterial products such as endotoxin is important for the diagnosis of Gram-negative infection and for the monitoring of its treatment. Further, it is important to identify patients with persistent subclinical level of bacterial products in their systemic circulation as data from animal studies also suggest this may be correlated with the onset of metabolic syndrome. In this review, we first aim to describe the principles of the Limulus amoebocyte lysate (LAL) test, an assay that is used to quantify endotoxin, and the various shortcomings that must be addressed before it can become a reliable means of quantifying endotoxin in samples derived from blood. We then review published data regarding endotoxin levels in healthy subjects and those with sepsis, inflammatory bowel disease, liver disorders and metabolic disorders such as obesity and diabetes. We also review the evidence regarding influence of macronutrients in augmenting the levels of systemic endotoxin. The results of this review show that reported mean levels of endotoxin in the systemic circulation of healthy humans and of those with various clinical disorders vary over a wide range. Further, this review shows that a significant proportion of this variation can be related to the method that was used to prepare plasma and serum samples prior to assay and its ability to reduce the effect of various blood borne factors that interfere with the LAL assay.