Is it true that PMX-DHP can improve lung oxygenation?

Polymyxin B immobilized fiber (PMX-R; Toray industries, Inc) has been developed in Japan for direct removal of endotoxin (PMX-DHP). PMX-DHP is used for treatment of patients with sepsis and septic shock primarily caused by Gram-negative infections, and its effectiveness of hemodynamic changes has been evaluated. In 119 cases (62 ± 16 years old, 82 men and 37 women) treated with PMX-DHP, changes in pulmonary oxygenation before and after PMX-DHP were examined, using PaO₂/FiO₂ as an oxygenation indicator, separately according to the outcome (80 survivors and 39 who died). Improvement of PaO₂/FiO₂ was identified in 64% of all cases. In the survival group, there appeared to be a trend for PaO₂/FiO₂ improvement as blood pressure increased. In the non-survival group, however, no improvement of PaO₂/FiO₂ was obtained, regardless of an increase of blood pressure. There was no significant correlation between PaO₂/FiO₂ and the rate of change in endotoxin levels, TNF-α, and IL-6. Granulocyte elastase increased significantly after PMX-DHP treatment in both groups. In the survival group, PaO₂/FiO₂ appeared to increase as macrophage inflammatory protein (MIP-1) 1-α decreased, suggesting the possibility that changes in MIP-1-α influenced PaO₂/FiO₂. As the mechanism for the improvement of pulmonary oxygenation by PMX-DHP has been shown clearly, it remains to be examined further.