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Updated: Aug 18, 2026

Three-Dimensionally Printed Microfluidic Cross-flow System for Ultrafiltration/Nanofiltration Membrane Performance Testing
Published on: February 13, 2016
An evaluation of the microbial retention performance of three ventilator-circuit filters
Objectives:
to determine and compare the microbial retention efficiency of 3 types of heat and moisture exchange (HME) filters.
Design:
randomised prospective study.
Setting:
Intensive Care Unit at the Middlesex Hospital and the microbiology laboratory of the Department of Academic Microbiology, University College London Medical School.
Measurements And Results:
An aerosol challenge to each filter using a suspension containing. S. marcescens and the bacteriophage MS2. In total 45 filters of 3 types were tested, 15 previously unused and 30 that had been used in ventilator circuits of 30 patients. The 3 types of filter generally had microbial retention efficiencies of > 99.99% for both S. marcescens and the bacteriophage MS2.
Conclusion:
The 3 types of HME filter were effective microbial filters and comparable in their microbial retention.
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