Polymyxin B-immobilized fiber column hemoperfusion mainly helps to constrict peripheral blood vessels in treatment for septic shock

BACKGROUND Polymyxin B-immobilized fiber column hemoperfusion (PMX) has been reported to be effective for patients with septic shock. It remains unclear, however, how the efficacy of PMX varies according to the characteristics and underlying conditions of the patients treated. The objective of the present study was to clarify the factors that result in clinical efficacy of PMX treatment. METHODS We retrospectively investigated 78 consecutive patients with severe sepsis or septic shock who underwent PMX treatment. We reviewed the demographic data, routine biochemistry, microbiological data, infection focus, Acute Physiology and Chronic Health Evaluation (APACHE) II score, Sequential Organ Failure Assessment (SOFA) score, change in mean arterial pressure (MAP), inotropic score, vasopressor dependency index, plasma levels of endotoxin and lactate, PaO2/FIO2 ratio, and survival time. We also divided the patients into two groups for comparison, namely, those whose inotropic scores improved after PMX treatment (improvement group) and those whose inotropic scores did not improve (non-improvement group). RESULTS The inotropic score and the vasopressor dependency index significantly decreased from 18.1 to 9.9 (p < 0.05) and from 0.27 to 0.14 (p < 0.05), respectively, after PMX treatment in the overall study population, while no significant change in the PaO2/FIO2 ratio was observed (p = 0.96). The inotropic score at pre-PMX treatment was significantly higher in the improvement group than in the non-improvement group (p < 0.01). The improvement of the PaO2/FIO2 ratio after PMX treatment was significant in the improvement group (p < 0.05). CONCLUSIONS The improvement group's inotropic score was higher, because of peripheral blood vessels dilatation and requirement for more catecholamines. Therefore, our study suggests that PMX treatment is particularly useful for improving hemodynamics in septic shock patients with excessively dilated peripheral blood vessels.