Prolonged direct hemoperfusion using a polymyxin B immobilized fiber cartridge provides sustained circulatory stabilization in patients with septic shock: a retrospective observational before-after study

BACKGROUND Direct hemoperfusion therapy with polymyxin B immobilized fiber cartridges (PMX-DHP) is widely used for septic shock in Japan and parts of Europe. Although this treatment is usually administered for 2 h, the optimal duration has not been established. METHODS This retrospective study compared the effects of prolonged and conventional PMX-DHP durations (2 and 12 h, respectively) for septic shock. Between October 2013 and March 2015, 18 patients underwent conventional PMX-DHP, and between April 2015 and May 2016, 18 patients underwent prolonged PMX-DHP. The primary outcome was the vasopressor dependency index during the 12 h after starting the first PMX-DHP session. The vasopressor dependency index was calculated as (inotropic score)/(mean blood pressure). RESULTS The patients' characteristics were almost similar in the conventional and prolonged PMX-DHP groups. The major site of infection was the abdomen in both groups (61 and 72%, respectively). The conventional PMX-DHP group had mean blood pressure values of 68.4 ± 8.9 mmHg and 78.2 ± 16.9 mmHg at 0 and 12 h after starting PMX-DHP (P = 0.13). The prolonged PMX-DHP group had mean blood pressure values of 70.3 ± 15.7 mmHg and 87.7 ± 16.9 mmHg at 0 and 12 h after starting PMX-DHP (P = 0.004). The conventional PMX-DHP group had vasopressor dependency index values of 0.52 ± 0.29 and 0.39 ± 0.25 at 0 and 12 h after starting PMX-DHP (P = 0.29). The prolonged PMX-DHP group had vasopressor dependency index values of 0.50 ± 0.26 and 0.28 ± 0.18 at 0 and 12 h after starting PMX-DHP (P = 0.01). Hospital mortality was similar in both groups (8/18 [44%] and 8/18 [44%]). CONCLUSIONS These findings suggest that prolonged PMX-DHP provides more sustained circulatory stabilization compared to conventional PMX-DHP. However, our study failed to detect any improvement in mortality. Well-designed prospective trials are needed to examine the clinical outcomes of prolonged PMX-DHP and to identify the optimal duration of PMX-DHP.