Sequential Versus Non-Sequential Polymyxin B Hemoperfusion in Severe Sepsis and Septic Shock: A Real-World Cohort Analysis of Survival in an Asian ICU

Background: Severe sepsis and septic shock remain major causes of ICU mortality despite advances in critical care. Polymyxin B hemoperfusion (PMX-HP) is widely used in Asia for refractory endotoxemia, yet the optimal session strategy remains unclear. Methods: We retrospectively analyzed adult ICU patients with severe sepsis or septic shock treated with PMX-HP between 2013 and 2019 in a tertiary center in Taiwan. Patients were divided into sequential (≥2 sessions within 24 h) and non-sequential groups. The primary outcome was 28-day mortality; secondary outcomes included ICU and hospital mortality, length of stay, organ support, and vasoactive-inotropic score (VIS) changes. Results: Among 64 patients, 33 (51.6%) received sequential therapy. The 28-day mortality was 46.9%, with no difference between groups after adjustment for baseline severity. Patients receiving sequential PMX-HP had longer hospital stays and more frequent CRRT use, likely reflecting greater underlying disease severity rather than a causal effect of treatment sequencing. Conclusions: Multivariate analysis identified higher APACHE II score, positive VIS change, and CRRT requirement as independent predictors of mortality. Sequential therapy itself was not associated with improved outcomes. Prognosis in PMX-HP-treated patients is determined mainly by underlying severity and hemodynamic instability, underscoring the need for patient selection and biomarker-guided strategies rather than routine sequential use.