Evidence and Perspectives on the Use of Polymyxin B-Immobilized Fiber Column Hemoperfusion among Critically Ill Patients

Background: Sepsis frequently leads to multiple organ failure due to the uncontrolled amplification and spread of inflammation, even if the infectious source is controlled. Lipopolysaccharide (LPS), a typical pathogen-associated molecular pattern (PAMP), is adsorbed by the polymyxin B-immobilized fiber column (PMX). PMX has been used for decades in Europe. Results of a North American randomized controlled trial (RCT) on PMX have recently been announced in a press release; results of large-scale observational studies and meta-analyses have also been reported in the last several years. Summary: To date, 3 multicenter RCTs on PMX hemoperfusion have been conducted outside of Japan. All of them enrolled postoperative patients with sepsis or septic shock secondary to intra-abdominal infection. However, confidence in the level of evidence provided by these RCTs is very low. Results from recent propensity-matched analyses and meta-analyses indicate that PMX hemoperfusion may improve survival outcomes among patients with sepsis. LPS is an important causative PAMP in sepsis; it triggers the immune response. PMX adsorbs LPS by using a polymyxin B-immobilized fiber that has high affinity for LPS. Moreover, PMX has other mechanisms of action, such as endogenous cannabinoid and activated neutrophil and monocyte adsorption, monocyte surface antigen alteration, and regulation of apoptosis in renal tubular cells. Furthermore, clinical research shows that PMX hemoperfusion can improve patients' hemodynamic status and pulmonary oxygenation and can sustain its endotoxin adsorption capability beyond 2 h. Improved pulmonary oxygenation among patients with sepsis-associated acute respiratory distress syndrome is linked to the effectiveness of PMX hemoperfusion in treating acute exacerbations of idiopathic pulmonary fibrosis (AE-IPF).