Evaluation of the endotoxin retention capabilities of inline intravenous filters

The capabilities of inline filters to retain bacteria and endotoxin were examined during simulated extended infusions for up to 168 hr. The tested inline filters were the ELD96 (Pall Biomedical Corp) and the IVEX 2 (Millipore Corp). Approximately 1 x 10(8) total cells of Escherichia coli B. were challenged to the upstream site of the filter. The test solution of 5% dextrose in water, 0.9% saline, Paremental A (A basic solution for total parenteral nutrition (TPN), a TPN solution in use in our clinic were infused continuously up to 168 hr and flow rate was maintained at 83 ml/hr. The effluents were analyzed using the Limulus Amebocyte Lysate (LAL) test to detect endotoxin and also passage of the challenged bacteria was tested at 24-hr intervals over 168 hr. The results were as follows: (1) The viability control culture showed the presence of viable bacteria throughout the 168-hr period of the experiment. (2) During the experiments, all filters produced sterile effluents. (3) LAL assay indicated that only the effluents from the ELD96 contained no detectable endotoxin for 168 hr.