Open Access

Elke Schmitt, Patrick Meybohm, Eva Herrmann, Karin Ammersbach, Raphaela Endres, Simone Lindau, Philipp Helmer, Kai Zacharowski, Holger Neb

• Background: The potential harmful effects of particle-contaminated infusions for critically ill adult patients are yet unclear. So far, only significant improved outcome in critically ill children and new-borns was demonstrated when using in-line filters, but for adult patients, evidence is still missing. Methods: This single-centre, retrospective controlled cohort study assessed the effect of in-line filtration of intravenous fluids with finer 0.2 or 1.2 μm vs 5.0 μm filters in critically ill adult patients. From a total of n = 3215 adult patients, n = 3012 patients were selected by propensity score matching (adjusting for sex, age, and surgery group) and assigned to either a fine filter cohort (with 0.2/1.2 μm filters, n = 1506, time period from February 2013 to January 2014) or a control filter cohort (with 5.0 μm filters, n = 1506, time period from April 2014 to March 2015). The cohorts were compared regarding the occurrence of severe vasoplegia, organ dysfunctions (lung, kidney, and brain), inflammation, in-hospital complications (myocardial infarction, ischemic stroke, pneumonia, and sepsis), in-hospital mortality, and length of ICU and hospital stay. Results: Comparing fine filter vs control filter cohort, respiratory dysfunction (Horowitz index 206 (119–290) vs 191 (104.75–280); P = 0.04), pneumonia (11.4% vs 14.4%; P = 0.02), sepsis (9.6% vs 12.2%; P = 0.03), interleukin-6 (471.5 (258.8–1062.8) ng/l vs 540.5 (284.5–1147.5) ng/l; P = 0.01), and length of ICU (1.2 (0.6–4.9) vs 1.7 (0.8–6.9) days; P <  0.01) and hospital stay (14.0 (9.2–22.2) vs 14.8 (10.0–26.8) days; P = 0.01) were reduced. Rate of severe vasoplegia (21.0% vs 19.6%; P > 0.20) and acute kidney injury (11.8% vs 13.7%; P = 0.11) was not significantly different between the cohorts. Conclusions: In-line filtration with finer 0.2 and 1.2 μm filters may be associated with less organ dysfunction and less inflammation in critically ill adult patients. Trial registration: The study was registered at ClinicalTrials.gov (number: NCT02281604).