Early introduction of hemoperfusion with an immobilized polymyxin B fiber column eliminates humoral mediators and improves pulmonary oxygenation

Introduction

We previously reported that early introduction of hemoperfusion with an immobilized polymyxin B fiber column (PMX-DHP) improved life expectancy. This time, we report that early introduction of PMX-DHP eliminates humoral mediators and improves pulmonary oxygenation.

Subjects and methods

Thirty-six sepsis patients were the subjects, consisting of 21 men and 15 women aged 62 ± 18.5 years. A thermodilution catheter was inserted in each patient, and the mixed venous oxygen saturation, oxygen delivery index, oxygen consumption index, and oxygen extraction ratio were measured. After it was confirmed that systemic oxygen metabolism was not impaired, PMX-DHP was started. Patients with uncontrolled infection were excluded from the study. The Acute Physiology and Chronic Health Evaluation (APACHE II) score was used as the index of severity, and survival of the patients was assessed after 1 month. The humoral mediators measured were IL-8 as a chemokine, plasminogen activator inhibitor-I (PAI-1) as an index of vascular endothelial cell activation, and polymorphonuclear neutrophil elastase (PMN-E) as an index of neutrophil activation. These mediators were measured before the start of PMX-DHP, and at 24, 48, and 78 hours after the start. The PaO₂/FiO₂ (P/F) ratio was used as an index of pulmonary oxygenation; it was measured before the start of PMX-DHP, and at 24, 48, 72, 92, and 120 hours after the start.

Results

Due to the early introduction of PMX-DHP with oxygen metabolism as the index, all the patients remained alive after 1 month. Before the start, the APACHE II score was 24 ± 2.0. Before treatment, the IL-8 level was 54 ± 15.8 pg/ml, but it decreased significantly from 48 hours onwards. PAI-1 was 133 ± 28.1 before treatment, but decreased significantly from 48 hours onwards. Similarly, PMN-E was also a high 418 ± 72.1 before treatment, but improved significantly from 48 hours onwards. The P/F ratio was 228 ± 68 before treatment, but improved significantly from 96 hours onwards.

Conclusion

The mechanism of action of PMX-DHP is still not fully understood, but the following findings were clarified from our investigation. (1) Early introduction of PMX-DHP improves life expectancy. (2) It is probable that changes of humoral mediators inhibit vascular endothelial cell activation, neutrophil activation, and chemokine activation. (3) It is probable that pulmonary oxygenation is improved due to elimination of humoral mediators.